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Perhaps the larges collection of all sorts of on-line schematics and links in the explored universe can be found Tomi Engdahl's Lights and Electronics Page.
There are many other documents at the Sci.Electronics.Repair (S.E.R) FAQWeb site or one of its mirror sites which may be of use in the design, testing, and repair of electronic equipment. The Main Table of Contents (ToC) provides links to a variety of information on troubleshooting and repair of many types of equipment, general electronics, an assortment of schematics, over 1,000 technology links, and much more. Most of these documents are nicely formatted, indexed, and cross-referenced. (Silicon Sam's Technology Resource, which may be present at this site and others, usually contains slightly more recent versions of many of these same documents but most of those under the S.E.R FAQ Main ToC are easier to use and the actual content differences are likely to be minor.)
The input voltage can range from about 5 to 24 V. Using a flyback from a MAC Plus computer which had its bad primary winding excised, an output of more than 20 kV is possible (though risky since the flyback is probably not rated for more than about 12 kV) from a 24 VDC, 2 A power supply. By adjusting the drive frequency and duty cycle, a wide range of output voltages and currents may be obtained depending on your load.
With the addition of a high voltage filter capacitor (.08 uF, 12 kV), this becomes a nice little helium neon laser power supply which operates on 8 to 15 VDC depending on required tube current and ballast resistor. See the document: Sam's Laser FAQ.
The drive transformer is from a B/W computer monitor (actually a video display terminal) and has a turns ratio of 4:1 wound on a 5/16" square by 3/8" long nylon bobbin on a gapped ferrite double E core. The primary has 80 turns and the secondary has 20 turns, both of #30 wire. Make sure you get the polarity correct: The base of the switching transistor should be driven when the driver turns on.
Where the flyback includes an internal rectifier and/or you are attempting to obtain the maximum output voltage of a specific polarity, the direction of drive matters as the largest pulse amplitude is generated when the switching transistor turns off. Since flyback transformers are not marked, you will have to try both possible connections to the drive coil. Use the one that produces the higher output voltage for a given set of input conditions (drive and pulse rate/width).
Many variations on this basic circuit are certainly possible. However, one nice thing about running it at 24 VDC or less is that it is much more difficult to let the smoke out of the circuit! The 5 A power supply I was using shut down on several occasions due to overcurrent but the only time I blew the chopper transistor was by accidentally shorting the base to collector.
These schematics are available in both PDF and GIF format.
Many modern gas stoves, ovens, furnaces, and other similar appliances use an electronic ignition rather than a continuously burning pilot flame to ignite the fuel. These are actually simple high voltage pulse generators.
C1 A D1 T1 o
H o----||----------------+-------|>|-------+-------+ +-----o HVP+
.1 uF D2 1N4007 | 1N4007 | | o ::(
250 V +----|>|----+ | +--+ ::(
| | | )::(
+---/\/\----+ | #20 )::( 1:35
| R1 1M | C2 _|_ )::(
| R2 / 1 uF --- +--+ ::(
| 18M \ DL1 400 V | __|__ ::(
| / NE-2 | _\_/_ +-----o HVP-
| | +--+ | / |
| +----|oo|----+---------' | SCR1
| C3 | +--+ | | | S316A
| .047 uF _|_ R3 / | | 400 V
| 250 V --- 180 \ | | 1 A
| | / | |
R4 2.7K | | | | |
N o---/\/\---+-----------+------------+----+-------+
The high-tech versions consist of a high voltage low current power supply and fluorescent (usually) lamp selected to attract undesirable flying creatures. (Boring low-tech devices may just use a fan to direct the insects to a tray of water from which they are too stupid to be able to excape!)
However, these devices are not selective and will obliterate friendly and useful bugs as well as unwanted pests.
Here is a typical circuit:
S1 R1 C1 C2 C1-C4: .5 uF, 400 V
H o----o/ o--+--/\/\--------||---+--------||---------+ D1-D5: 1N4007
| 25K D1 | D2 D3 | D4
| +---|>|---+---|>|---+---|>|---+---|>|---+
+-+ | C3 | C4 |
AC Line |o| FL1 +---+----||----+----+---+----)|----+----+--o +
+-+ Lamp | | R3 | | R4 | 500 to
| | +---/\/\---+ +---/\/\---+ 600 V
| R2 | 10M 10M to grid
N o----------+--/\/\---+------------------------------------------o -
25K
This is just a line powered voltage quadrupler. R1 and R2 provide current
limiting when the strike occurs (and should someone come in contact with the
grid). The lamp, FL1, includes the fluorescent bulb, ballast, and starter (if
required). Devices designed for jumbo size bugs (or small rodents) may use
slightly larger capacitors!This module produces both positive and negative outputs when connected to 115 VAC, 60 Hz line voltage. Each is about 5 kV at up to around 5 uA. It is probably similar to the high voltage power supply in the AirEase(tm) Personal Space Ionization Air Cleaner from Ion Systems, Inc., a small table top unit. (Unfortunately, the HV module in the AirEase was totally potted so I could not determine anything about its internal circuitry.)
D1 T1 o
H o--------------|>|----+---+--------------------+ +-----o A
1N4007 | | Sidac __|__ SCR1 ::(
| | R3 D2 100 V _\_/_ T106B2 ::(
AC C1 | +--/\/\---|>| / | 200 V ::(
Line Power .15 uF _|_ 1.5K |<|--+--' | 4 A o ::( 350 ohms
IL1 LED 250V --- _|_ | +-------+ ::(
+--|<|---+ | C2 --- | | )::(
| R1 | R2 | .0047 uF | | | .1 ohm )::(
N o---+--/\/\--+--/\/\--+ +-----+--+ )::(
470 3.9K | +--+ +--+--o B
1 W 2 W | | R4 |
+--------------------------------+---/\/\---+
2.2M
The AC input is rectified by D1 and as it builds up past the threshold of the
sidac (D2, 100 V), SCR1 is triggered dumping a small energy storage capacitor
(C1) through the primary of the HV transformer, T1. This generates a HV pulse
in the secondary. In about .5 ms, the current drops low enough such that the
SCR turns off. As long as the instantaneous input voltage remains above about
100 V, this sequence of events repeats producing a burst of 5 or 6 discharges
per cycle of the 60 Hz AC input separated by approximately 13 ms of dead time.The LED (IL1) is a power-on indicator. :-)
The transformer was totally potted so I could not easily determine anything about its construction other than its winding resistances and turns ratio (about 1:100).
A o
C3 |
+------||-------+
R5 R6 D3 | D4 D5 | D6 R7 R8
HV- o--/\/\---/\/\--+--|>|--+--|>|--+--|>|--+--|>|---/\/\--+--/\/\--o HV+
10M 10M | C4 | 220K | 10M
+------||-------+ |
D3-D6: 10 kV, 5 mA _|_ _|_
C3,C4: 200 pF, 10 kV --- C5 --- C6
C5,C6: 200 pF, 5 kV | |
B o--+----------------------+
The secondary side consists of a voltage tripler for the negative output
(HV-) and a simple rectifier for the positive output (HV+). This asymmetry is
due to the nature of the unidirectional drive to the transformer primary.>From my measurements, this circuit produces a total of around 10 kV between HV+ and HV-, at up to 5 uA. The output voltages are roughly equal plus and minus when referenced to point B.
I assume the module would also operate on DC (say, 110 to 150 V) with the discharges repeating continuously at about 2 kHz. Output current capability would be about 5 times greater but at the same maximum (no load) voltage. (However, with DC, if the SCR ever got stuck in an 'on' state, it would be stuck there since there would be no AC zero crossings to force it off. This wouldn't be good!)
The secondary side circuitry can be easily modified or redesigned to provide a single positive or negative output or for higher or lower total voltage. Simply removing R4 will isolate it from the input and earth ground (assuming T1's insulation is adequate).
Where there is no high voltage from such a device, check the following:
DL1 +-+ |
o T1 +-------+-----|o|
+12 o---+--------+----------+---------------------+ ::( | +-+ |
| | | D 30T )::( | DL2 +-+
| | -_|_ 4.7uF #30 )::( +-----|o| |
| | --- 50V +------+ ::( 3000T | +-+
| _|_ C2 + | | ::( #44 | DL3 +-+ |
| --- 470pF +--------------|------+ ::( +-----|o|
| | | | F 30T )::( | +-+ |
+_|_ C1 | | D1 | #36 )::( | DL4 +-+
--- 33uF +----------|---+---|<|----|------+ ::( +-----|o| |
- | 16V | | | 1N4002 | o +--+ +-+
| / / | |/ C o | |
| R1 \ R2 \ +--------|Q1 TIP41 +--------------+
| 1K / 4.7K / |\ E | Grid
| \ \ | |
| | | | |
GND o---+--------+----------+--------------+--------------+
T1 is constructed on a 1/4" diameter ferrite core. The D (Drive) and F
(Feedback) windings are wound bifilar style (interleaved) directly on the
core. The O (Output) winding is wound on a nylon sleeve which slips over
the core and is split into 10 sections with an equal number of turns (100
each) with insulation in between them.DL1 to DL4 look like neon light bulbs with a single electrode. They glow like neon light bulbs when the circuit is powered and seem to capacitively couple the HV pulses to the grounded grid in such a way to generate ozone. I don't know if they are filled with special gas or are just weird neon light bulbs.
An ultrasonic cleaner contains a power oscillator driving a large piezoelectric transducer under the cleaning tank. Depending on capacity, these can be quite massive.
A typical circuit is shown below. This is from a Branson Model 41-4000 which is typical of a small consumer grade unit.
R1 D1
H o------/\/\-------|>|----------+
1, 1/2 W EDA456 |
C1 D2 |
+----||----+----|>|-----+
| .1 uF | EDA456 | 2
| 200 V | +-----+---+ T1 +---+------->>------+
| R2 | _|_ C2 ):: o 4 | | |
+---/\/\---+ --- .8 uF D ):: +----+ | |
| 22K _|_ 200 V )::( + |
| 1 W - 1 o )::( ):: _|_
+-----------------+---------+ ::( O ):: L1 _x_ PT1
| R3 | 7 ::( ):: |
| +---/\/\---+ +-----+ ::( 5 + |
C \| | 10K, 1 W | F ):: +---+ | |
Q1 |--+-+--------------+ 6 o ):: | | |
E /| | D3 R4 +---+ +----+------->>------+
| +--|<|---/\/\--+ _|_
| 47, 1 W | --- Input: 115 VAC, 50/60 Hz
| | | Output: 460 VAC, pulsed 80 kHz
N o------+-------------------+---+
The power transistor (Q1) and its associated components form an self excited
driver for the piezo-transducer (PT1). I do not have specs on Q1 but based on
the circuit, it probably has a Vceo rating of at least 500 V and power rating
of at least 50 W.Two windings on the transformer (T1, which is wound on a toroidal ferrite core) provide drive (D) and feedback (F) respectively. L1 along with the inherent capacitance of PT1 tunes the output circuit for maximum amplitude.
The output of this (and similar units) are bursts of high frequency (10s to 100s of kHz) acoustic waves at a 60 Hz repetition rate. The characteristic sound these ultrasonic cleaners make during operation is due to the effects of the bursts occuring at 60 Hz since you cannot actually hear the ultrasonic frequencies they use.
The frequency of the ultrasound is approximately 80 kHz for this unit with a maximum amplitude of about 460 VAC RMS (1,300 V p-p) for a 115 VAC input.
WARNING: Do not run the device with an empty tank since it expects to have a proper load. Do not touch the bottom of the tank and avoid putting your paws into the cleaning solution while the power is on. I don't know what, if any, long term effects there may be but it isn't worth taking chances. The effects definitely feel strange.
Where the device doesn't oscillate (it appears as dead as a door-nail), first check for obvious failures such as bad connections and cracked, scorched, or obliterated parts.
To get inside probably requires removing the bottom cover (after pulling the plug and disposing of the cleaning solution!).
CAUTION: Confirm that all large capacitors are discharged before touching anything inside!
The semiconductors (Q1, D1, D2, D3) can be tested for shorts with a multimeter (see the document: Basic Testing of Semiconductor Devices.
The transformer (T1) or inductor (L1) could have internal short circuits preventing proper operation and/or blowing other parts due to excessive load but this isn't kind of failure likely as you might think. However, where all the other parts test good but the cleaning action appears weak without any overheating, a L1 could be defective (open or other bad connections) detuning the output circuit.
Where the transistor and/or fuse has blown, look for a visible burn mark on the transducer and/or test it (after disconnecting) with a multimeter. If there is a mark or your test shows anything less than infinite resistance, there may have been punch-through of the dielectric between the two plates. I don't know whether this could be caused by running the unit with nothing in the tank but it might be possible. If the damage is localized, you may be able to isolate the area of the hole by removing the metal electrode layer surrounding it to provide an insulating region 1/4 inch in diameter. This will change the resonant frequency of the output circuit a small amount but hopefully not enough to matter. You have nothing to lose since replacing the transducer is likely not worth it (and perhaps not even possible since it is probably solidly bonded to the bottom of the tank).
When testing, use a series light bulb to prevent the power transistor from blowing should there be a short circuit somewhere (see the document: Troubleshooting and Repair of Consumer Electronic Equipment) AND do not run the unit with and empty tank.
This is also the simplest and safest way to construct a small DC power supply as you do not need to deal with the 110 VAC at all.
To convert such an adapter to DC requires the use of:
The basic circuit is shown below:
Bridge Rectifier Filter Capacitor
AC o-----+----|>|-------+---------+-----o DC (+)
~| |+ |
In from +----|<|----+ | +_|_ Out to powered device
AC wall | | C ___ or voltage regulator
Adapter +----|>|----|--+ - |
| | |
AC o-----+----|<|----+------------+-----o DC (-)
~ -
Considerations:
Therefore, you will need to find an AC wall adapter that produces an output voltage which will result in something close to what you need. However, this may be a bit more difficult than it sounds since the nameplate rating of many wall adapters is not an accurate indication of what they actually produce especially when lightly loaded. Measuring the output is best.
The following is a very basic introduction to the construction of a circuit with appropriate modifications will work for outputs in the range of about 1.25 to 35 V and currents up 1 A. This can also be used as the basis for a small general purpose power supply for use with electronics experiments.
What you want is an IC called an 'adjustable voltage regulator'. The LM317 is one example - Radio Shack should have it along with a schematic. The LM317 looks like a power transistor but is a complete regulator on a chip.
Here is a sample circuit:
I +-------+ O
Vin (+) o-----+---| LM317 |---+--------------+-----o Vout (+)
| +-------+ | |
| | A / |
| | \ R1 = 240 |
| | / | ___
_|_ C1 | | +_|_ C2 |_0_| LM317
--- .01 +-------+ --- 1 uF | | 1 - Adjust
| uF | - | |___| 2 - Output
| \ | ||| 3 - Input
| / R2 | 123
| \ |
| | |
Vin(-) o------+-------+----------------------+-----o Vout (-)
Note: Not all voltage regulator ICs use this pinout. If you are not using an
LM317, double check its pinout - as well as all the other specifications.
For a single output not referenced to a common, it doesn't matter
whether a positive voltage regulator (as shown) or negative voltage regulator
is used. However, were multiple power supplies like this are needed WITH a
common point, negative voltage regulator ICs must be used for the negative
ones.Here are pinouts for the most common types:
78xx (Fixed Pos) 79xx (Fixed Neg) LM317 (Adj Pos) LM337 (Adj Neg) ___ ___ ___ ___ |_O_| |_O_| |_O_| |_O_| | | 1 = Input | | 1 = Common | | 1 = Adjust | | 1 = Adjust |___| 2 = Common |___| 2 = Input |___| 2 = Output |___| 2 = Input ||| 3 = Output ||| 3 = Output ||| 3 = Input ||| 3 = Output 123 123 123 123
For the LM317:
However, note that a typical adapter's voltage may vary quite a bit depending on manufacturer and load. You will have to select one that isn't too much greater than what you really want since this will add unnecessary wasted power in the device and additional heat dissipation.
Using 10,000 uF per *amp* of output current will result in less than 1 V p-p ripple on the input to the regulator. As long as the input is always greater than your desired output voltage plus 2.5 V, the regulator will totally remove this ripple resulting in a constant DC output independent of line voltage and load current fluctuations. (For you purists, the regulator isn't quite perfect but is good enough for most applications.)
Make sure you select a capacitor with a voltage rating at least 25% greater than the adapter's *unloaded* peak output voltage and observe the polarity!
Note: wall adapters designed as battery chargers may not have any filter capacitors so this will definitely be needed with this type. Quick check: If the voltage on the adapter's output drops to zero as soon as it is pulled from the wall - even with no load - it does not have a filter capacitor.
28VCT,1A
H o--+ T1
)|| D1 V+ In +------+ Out
)|| +--+--|>|-----+--------------+----| 7815 |---------+----o +15 VDC
)||( ~| D2 | C1 +_|_ +------+ C3 +_|_
)||( +--|<|--+ | 5,000uF --- Com | 10uF ---
)||( L1 | | 25V - | | 25V - |
110 VAC )|| +----------------------------+--------+------------+--+-o Analog
)||( L2 D3 | | C2 +_|_ | C4 +_|_ V Common
)||( +--|>|--|--+ 5,000uF --- Com | 10uF ---
)||( ~| D4 | 25V - | +------+ 25V - |
)|| +--+--|<|--+-----------------+----| 7915 |---------+---o -15 VDC
)|| V- In +------+ Out
N o--+ D1-D4: 1N4007 or 2 A bridge
Note: Pinouts for 78 and 79 series parts are NOT the same!For an unregulated supply, take the outputs from V+ and V-.
Here is a circuit for a +/- 12 VDC supply:
12V,1A
H o--+ T1
)|| D1 V+ In +------+ Out
)|| +--+--|>|------------+----| 7812 |---------+----o +12 VDC
)||( | C1 +_|_ +------+ C3 +_|_
110 VAC )||( | 10,000uF --- Com | 10uF ---
)||( | 25V - | | 25V - |
)|| +--|-----------------+--------+------------+--+-o Analog
)|| | C2 +_|_ | C4 +_|_ V Common
N o--+ | 10,000uF --- Com | 10uF ---
| D2 25V - | +------+ 25V - |
+--|<|------------+----| 7912 |---------+---o -12 VDC
V- In +------+ Out
For an unregulated supply, take the outputs from V+ and V-.Since only half-wave rectification is used, the main filter caps, C1 and C2, should be at least twice the uF value compared to full wave or bridge circuits to obtain the same ripple.
Another disadvantage of this configuration is that if the currents drawn from the outputs aren't equal, net DC flows through the transformer secondary (with a voltage doubler having no output connection to the common point, this isn't possible). Core saturation may result if operating near the transformer's maximum current ratings.
E C
+-----. Q1 .-------------+
| _\___/_ |
| B| |
| R1 | I +------+ O |
Vin (+) o---+--/\/\--+-+---| 7805 |---+-+-----o Vout (+)
5 | +------+ | ___
| | C | |_O_| 7805
_|_ C1 | +_|_ C2 | | 1 - Input
--- .01 | --- 1 uF |___| 2 - Common
| uF | - | ||| 3 - Output
| | | 123
Vin(-) o---------------+-------+--------+-----o Vout (-)
The way this works is that once the current exceeds about Vbe(Q1)/5 A, Q1
turns on and bypasses current around the 7805.For a negative supply based on a 79xx regulator, use an NPN transistor like a 2N3055 and reverse the capacitor polarities. Don't forget that the pinout for the 79xx and other negative voltage regulators is NOT the same as for the positive variety. See the section: Adding an IC Regulator to a Wall Adapter or Battery.
+-------------------.C E.-------+
| Q2 _\___/_ |
| 2N3055 | |
| | R5 |
+---------.E C.------+---/\/\---+
| Q1 _\___/_ 500 |
| 2N2905 | |
| / R4 |
| \ 5K |
| / |
| R3 | I +-------+ O | 1N4002
Vin (+) o---+-+---/\/\---+---| LM317 |---+----+--+------+-------+---o Vout (+)
| 22 +-------+ | | | |
| | A / _|_ | |
| | \ R1 /_\ D1 | |
| | / 120 | | |
_|_ C1 | | | +_|_ C2 /
--- 10uF +-------+---+---+ --- 47uF \ RL*
| | | - | /
| \ R2 +_|_ C3 | |
| +->/ 5K --- 10uF | |
| | \ - | | |
| | | | | |
Vin(-) o------+---------------+--+-----------+----------+-------+---o Vout (-)
* For proper regulation, RL must be low enough in value to guarantee at least a
30 mA current at the selected output voltage. It can be a separate resistor
or part of the actual load.For even higher current operation, multiple power transistors (Q2) can be wired in parallel as a pass-bank with small (e.g., .1 ohm) emitter resistors to balance the load. In this case, Q1 may need to be a slightly bigger transistor and R4 reduced in value to provide adequate base drive. Details will depend on your particular needs.
As with the other circuits, a negative power supply can be constructed by using the appropriate regulator IC, swapping NPN or PNP transistors, and reversing all the polarities of the capacitors and diode.
IC1
I +--------+ O
+----+--------+---| LT1084 |--+-------+-----o + 1.5 VDC
T1 | | | +--------+ | |
H o--+ | | | | A / R1 |
)|| +-+ | | | \ 220 |
)||( | | | / | ___ IC1
115 )||( 4V _|_ C1 _|_ C2 | | +_|_ C3 | 0 | LT1084CP
VAC )||( --- 10K --- 10K +-------+ --- 470uF | | 1 - Adjust
)||( | uF | uF | - | 6.3V |___| 2 - Output
)|| +-+ | 10V | 10V \ R2 | ||| 3 - Input
N o--+ | | | / 62 | 123
| | | \ | Front View
| | | | |
+----+--------+-------+---------------+-----o Return
The power transformer (T1) that I used was actually rewound from one that
was rated at 12 V, 1 A. This was a high quality transformer, so removing
2/3rds of the secondary was quite a pain. Actually, the purpose was an
experiment to see if it could be done non-destructively. Conclusions: Just
barely :-). Obviously, a transformer actually designed to produce about
4 or 5 V at 3 A could also be used.The regulator (IC1) is an LT1084CP which is similar to an LM317 but is a low dropout type rated at 5 A max. I had a pile of these left over from a certain multi-million dollar project that had been cancelled due to upper management foot in a** disease.....
Despite the transformer only being rated for 1 A, with IC1 on a modest heatsink, the supply seems perfectly happy putting out 3 A at 1.5 V for an extended period. I don't know that I would run it all day at this high current but for my purposes, it seems fine.
It turns out that the typical electronic flash circuit from a disposable camera like the Kodak MAX (see Schematic and Photo), actually draws more than 3 A at the start of its recharge cycle. So, the voltage does dip a bit but this doesn't affect much of anything. Recharge time with the power supply is at least as rapid as with a fresh Alkaline cell. The voltage from an Alkaline cell also dips a bit under these conditions :-).
Obviously, the circuit could be easily modified to put out 2.4 VDC (for a pair of NiCd cells), 3 VDC (for two Alkalines), or whatever else you might need.
Errors in transcription are possible. Some models use additional outputs each fed from a single rectifier diode and filter capacitor (not shown). Some part numbers and the connector pinout may not be the same for your particular VCR.
A totally dead supply with a blown fuse usually means a shorted switchmode power transistor, Q1. Check all other components before applying power after replacement as other parts may be bad as well.
The most common problems resulting in low or incorrect outputs are dried up or leaky electrolytic capacitors - C4, C16, C17, C21.
See the document: Notes on the Troubleshooting and Repair of Small Switchmode Power Supplies for more info.
These schematics are available in both PDF and GIF format:
The AC line input and degauss components are at the upper left, the SMPS chopper, its controller, and feedback opto-isolator are in the lower left/middle, and the secondaries - some with additional regulation components - occupy the entire right side of this diagram. Even for relatively basic application such as this, the circuitry is quite complex. There are more than a half dozen separate outputs regulated in at least 3 different ways!
The variable voltage B+ regulator is in the upper right corner. This provides an voltage to power the horizontal deflection which is determined by the video input. To maintain the same picture width, the required voltage to the horizontal output transistor/flyback needs to be roughly proportional to horizontal scan rate.
However, the circuit described in the section: Super Simple
Inverter" only requires off-the-shelf components but has a pitiful efficiency.
But construction is, well, super simple :-).
And, it should be easy to make modifications to the flash units from pocket
or disposable cameras as described in the section: Up to 350
VDC Inverter from 1.5 V Alkaline Cell since these are quite readily
available for free if you know where to ask!
For more information on fluorescent and xenon lamps, see the documents:
Fluorescent Lamps,
Ballasts, and Fixtures and
Notes on the
Troubleshooting and Repair of Electronic Flash Units and Strobe Lights and
Design Guidelines, Useful Circuits, and Schematics, respectively.
Output depends on input voltage. Adjust for your application. With the
component values given, it will generate over 400 V from a 12 V supply and
charge a 200 uF capacitor to 300 V in under 5 seconds.
For your less intense applications, a fluorescent lamp can be powered directly
from the secondary (without any other components). This works reasonably well
with a F13-T5 or F15-T12 bulb (but don't expect super brightness). Q1 does
get quite hot so use a good heat sink.
The AmerTac Fluorescent Lamp Ballast is from a
portable 12 V light made in China for American Tack & Hardware Co sold in Home
Depot stores. It burned out after about 30 minutes of continuous use. (OK,
maybe you shouldn't consider duplicating this exactly! --- Sam) So I decided
to take it apart and see what was in there.
What it had was a very small circuit board (about 1/2" x 2"). Both the
transformer and the transistor were melted beyond recognition. The
transformer was apparently custom made out of two 'E' cores taped together.
I have another identical unit, so I could read the transistor part number:
2SD882. It is rated 80 V, 5 A, 40 W, typical Hfe of 30, in a TO127 package.
Unlike many of the others, this circuit powers both both filaments in the tube
but is otherwise very similar.
I have another identical unit which hasn't been fried so I put a UV bulb in
there and fired it up. It is clear that only one end has a glowing filament.
It is the end connected to pins 5 & 6 of the transformer. The filament
attached to pins 1 and 2 appears to only work as a resistor. The circuit will
not operate without the bulb so I wasn't able to get reliable readings.
This design can easily be modified for many other uses at lower or higher
power.
The 315T O (Output) is wound first followed by the 28T D (Drive) and 28T F
(Feedback) windings. There should be a strip of mylar insulating tape
between each of the windings.
The number of turns were estimated without disassembly as follows:
Since it is very low power, no heat sink is used in the Archer flashlight.
However, for other applications, one may be needed.
This design is very similar to the Archer model (see the section:
Archer Mini Flashlight Fluorescent Lamp Inverter, but
eases starting requirements by actually heating one of the filaments of the T5
lamp. Thus, a lower voltage transformer can be used.
The 160T O (Output) is wound first followed by the 16T H (Heater), 32T D
(Drive), and 16 T F (Feedback) windings. There should be a strip of mylar
insulating tape between each of the windings.
The number of turns were estimated after unsoldering the transformer from
the circuit board as follows:
Since it is very low power, no heat sink is used in the Energizer
flashlight. However, for other applications, one may be needed.
This was reverse engineered from a toy pocket blacklight, made in China.
It has been tested with tubes up to 6 W.
This design can easily be modified for many other uses at lower or higher
power. Note that its topology is similar to that of the circuit described
in the section: Super Simple Inverter.
The 350T O (Output) is wound first followed by the 25T D (Drive) and 18T F
(Feedback) windings. There should be a strip of mylar insulating tape
between each of the windings.
The number of turns were estimated without disassembly as follows:
Since it is very low power, no heat sink is used in this lamp. However,
for other applications, one may be needed.
The tube seems to like 75 VAC in order to 'fire it up'.
I used a 2N3053 transistor and a commonly available
commercial 6 - 0 - 6 primary 240VAC 100mA secondary transformer.
After 25 minutes constant usage, both transistor and transformer
remained cool.
A variable PSU was connected, and the circuit worked first time. The required
75 VAC output was achieved with only 5 VDC input.
The core is just a straight piece of ferrite 1/4" x 1/4" x 1-3/8" It is
fully open - there is no gap.
Use a good heat sink for continuous operation at higher power levels (6 V
input or above). The type used (2SC1826) was a replacement after I fried
the unidentified transistor originally installed (103-SV2P001).
Like a regular manual start preheat fluorescent fixture, the start switch,
must be depressed until the lamp comes on at full brightness indicating that
the filaments are adequately heated.
I have used it with fluorescent tubes of many sizes: F6-T5, F13-T5, F15-T12,
and F20-T12. The arc will be sustained with the filaments hot on an input
as low as about 3.5 to 4 V (with a new tube) but during starting, an input
voltage of about 5 or 6 V may be needed until the filaments are hot enough
to sustain the arc at the lower voltage.
Two nearly identical circuits are shown.
The measured input current at various input voltages for two lamp types are
shown in the chart below. SV (Starting Voltage) is the minimum input voltage
required to preheat the filaments before the lamp will turn on (current is
lower until filaments are hot). FB (Full Brightness) is the point at which
the lamp appears to be operating at the same intensity as if it were installed
in a normal 115 VAC fixture.
Each E core is 1" x 1/2" x 1/4" overall. The outer legs of the core are
1/8" thick. The central leg is 1/4" square. The square nylon bobbin has
a diameter of 5/16" and length of 3/8".
The 600T O (Output) is wound first followed by the 15T D (Drive) and 10T F
(Feedback) windings. For convenience, wind the D and F windings bifiler
style (the two wires together). Determine the appropriate connections
with an ohmmeter (or label the ends). The centertaps are brought out to
terminals. Try to distribute the O winding uniformly across the entire
bobbin area by winding it in multiple layers. This will assure that no
wires with a significant voltage difference are adjacent. There should be
a strip of insulating tape between the O and the other windings.
For operation above about 6 V, a pair of good heat sinks will be required.
However, power dissipation in the transistors does not seem to increase
as much as expected - the base drive is probably more optimal at higher
input voltage.
Modifications for higher or lower output voltage are easily achieved. For
example, a fast cycle strobe requiring 330 VDC, would only require using three
times the number of turns on the Output winding and the addition of a bridge
rectifier to charge the energy storage capacitor(s). Alternatively, the
inverter could be used as-is with the addition of a voltage tripler. A tripler
rather than doubler is needed because of the squarewave output. (The RMS and
peak voltages are the same so you don't get the boost of 1.414 as you do with
the sinusoidal waveform from the power company.)
The core dimensions are 3-3/4" x 3-1/8" x 1-1/8" overall. The outer legs
of the core are 5/8" thick. The central leg is 1" wide. The square bobbin
has a diameter of 1-3/8".
The 360T O (Output) secondary is wound first as 4 or 5 insulated layers
followed by the 31T D (Drive) and 17T F (Feedback) windings. There are
insulating layers between each of the windings.
The number of turns were estimated without disassembly as follows:
The transistors are mounted on heat sinks which form the sides of the case.
The specific circuit described below is derived from the inverter used in a
Kodak "MAX" disposable camera electronic flash. The beauty of this approach
is that the remains of these cameras are often available for the asking at 1
hour photo developing outfits since they are usually thrown away after
extracting the film (though apparently some are recycled, this is probably
the exception rather than the rule).
The original Kodak MAX Flash Unit Schematic and Photo of Kodak MAX Flash Unit
show what you get for nothing. All newer Kodak disposable cameras including
the "Funsaver Sure Flash" and APS (Advanced Photo System) "ADVANTIX" appear to
use a similar if not identical circuit but I haven't disassembled one of those
as yet.
This is certainly useful intact for strobe and high voltage projects but for
the purposes of this discussion, all we need are T1 (which we may modify), Q1,
R1, perhaps S1 or an equivalent, C1, and D1.
By rewinding the inverter transformer, any output voltage up to about 350 VDC
can be obtained from a 1.5 V Alkaline cell. More than 350 V is probably
possible but just thinking about winding the needed secondary makes me tired!
The Mini Power Supply Based on Modified Kodak MAX
Inverter shows the simplified circuit. The original circuit board can be
used and is very convenient though a more compact unit can be constructed if
you use a bit of perf board or your on PCB. Note that for higher voltages, Q2
in the original MAX schematic may be needed. For low voltage operation,
performance is much better without it. I don't know what the break-even point
is so you may want to leave a spot for Q2 just in case.
The main difficulty is in disassembling T1 in a nondestructive way. It seems
that the ferrite core is held together by an adhesive which is very tough and
resistant to any solvent that won't destroy the plastic bobbin and wire
insulation as well. Therefore, you may need to sacrifice two of these - one
so that just the ferrite core can be salvaged by soaking the transformer in
some nasty solvent (maybe lacquer thinner will work) to dissolve the adhesive.
For the 6 turn primary, the number of turns required on the secondary is
approximately:
So for: 4 VDC, N = 26; for 50 VDC, and for N = 256 300 VDC, N = 1506.
The original circuit topped out at about 350 VDC with N = 1750.
It may be possible to use multiple output windings to provide more than one
output voltage but as will be shown below, all output power must be drawn on
the forward stroke of the converter since the flyback pulse of the reverse
stroke is needed to drive the voltage on C1 and the base of Q1 negative.
I have done the modifications for the 4 VDC version by removing the original
1,750 turn secondary (I had to do this anyway so I could confirm the number
of turns for the circuit description) and replacing it with a 26 turn winding
of #32 wire. Unfortunately, I also had to Epoxy the half dozen pieces of the
ferrite core back together after somewhat destructive disassembly but I don't
think there are any significant gaps left in the core :-( (I confirmed that
the transformer still worked by installing another set of undamaged original
windings and checking that it still charged and fired the flash properly).
With no load, the output reaches about 5 V in a fraction of a second.
With a 100 ohm load, the output drops to a bit over 4 V.
Following a post to sci.electronics.design suggesting this circuit as a simple
way of obtaining a dual op-amp supply from a single Alkaline cell (dual part
as yet to be tested), we have the following discussion on the theory of
operation of this circuit:
(From: Tony Williams (tonyw@ledelec.demon.co.uk).)
Q1 bottoming-V is going to vary from about 0.1V to about 0.3V on the
forward stroke, from no-load to full-load.
D1 + Q1Vbe fwd-drop is going to similarly vary from about
(0.7 + 0.35)V to (0.7 + 0.6)V.
V/C2(NLoad) = (1.5 - 0.1)26/6 - 1.05 = 5.02V.
4 V across 100 ohms is about 160 mW, not bad really.
Well, I still haven't seen what recharges C1 negatively. Some scope
waveforms for C1 and D1 would be nice (hint, hint). :)"
Some additional info (after I took the hint) finally appears to have solved
the mystery:
I checked the waveform across B-E of Q1. It is around .6 V for most of the
cycle with strong -6 V going spikes! So, where are they coming from????
Possible sources include:
Now, here is the kicker (no pun....):
Monitoring the waveform ACROSS D1 - do you want to guess what it looks like?
We have a greater than 110 V, 200 ns spikes occurring when Q1 switches off!
Geez! 110 V from a 26 turn winding and a 1.5 V battery! It wouldn't take much
capacitance or reverse recovery leakage through D1 to drive the base and C1
negative by 6 V. Looking at the equivalent circuit:
Tony replies to this new information:
Think varactor-action. For D1 being spiked from fwd conduction to 110 V
negative I would suspect that a 26pF-equivalent for D1 is quite reasonable.
Bearing in mind that we have an inherent reverse-Vbe clamp I would not even
be surprised if D1 could also be allowed to avalanche."
And, Tony's reply:
If there are any BOFs around; I think Jevon Crossthwaite, in his
early days, worked for Sylvania and for George Philbrick (before
and after Teledyne entered the scene), both in the States."
This circuit (referenced in the document:
Notes on the
Troubleshooting and Repair of Electronic Flash Units and Strobe Lights and
Design Guidelines, Useful Circuits, and Schematics is designed to provide
a variety of options in terms of repetition rate, flash intensity, and various
repeat and triggering modes.
The design includes:
Parts of this circuit have been built and tested but the entire unit is not
complete. Maybe someday.... :-)
These schematics are available in both PDF and GIF format.
(The following two sections are from: Kevin Horton (khorton@tech.iupui.edu).)
I'm building a super strobe bar! It has 8 strobe tubes under computer
control. (Actually a PIC processor, but hey, computer is a computer.)
I have all the stuff done except the control section, and I only have
2 of the 8 strobe units done due to the fact that I haven't found any
more cheap cameras at the thrift store! (One Saturday morning's worth of
garage sales and flea markets would remedy that! --- sam).
It runs on 12 V, at up to 6 A, and can fire the tubes at a rate of about 8-10
times per second. The storage cap is a 210 uf, 330 V model; it gets to about
250 V to 300 V before firing; depending on how long it has had to charge.
Because of this high speed, the tubes get shall we say, a little warm. (Well,
maybe a lot warm --- sam). I have it set up at the moment driving two
alternating 5 W-s tubes. I'm pumping them quite a bit too hard, as the
electrodes start to glow after oh, about 5 seconds or so of continuous use.
I know, a high class problem, indeed! My final assembly will have 8 tubes
spaced about 8 inches apart on a 2x4, with a Plexiglass U-shaped enclosure
with a nice 12 V fan blowing air through one end of the channel to cool the
inverter and the tubes. Stay tuned.
Inverter - High power 12 V to 300 V inverter for high repeat rate medium
power strobes. Schematic in GIF format: inverter.gif
Trigger - Opto-isolated logic level trigger for general strobe applications.
Schematic in GIF format: trigger.gif
I have developed a cool little transformer circuit that seems to be
very efficient. I built this inverter as tiny as I could make it.
It runs off of 3V, and charges up a little 1 uf 250V cap all the way up in
about 30 seconds; drawing about 5 to 8 mA in the process. The numbers by the
windings tell the number of turns. The primary and feedback windings are
#28, while the secondary is #46. Yes, #46! I could hardly tell what
gauge it was, as it was almost too small to measure with my micrometer!
It may be #44 or #45, but at these sizes, who knows? I used a trigger
transformer for the wire. I used all the wire on it, to be exact; it
all JUST fit on the little bobbin. The primary went on the core first,
then the secondary, and finally the feedback winding. This order is
very important. I used a ferrite bobbin and corresponding ferrite 'ring'
that fit on it. The whole shebang was less than 1 cm in diameter, and
about 3-5 mm high! I gave it a coat of wax to seal things up, and made
the inverter circuit with surface-mount parts, which I then waxed onto the
top. There are two wires in, and two wires out. It's enough to run a
neon fairly brightly at 1.2 V, with a 3 ma current draw.
Schematic in GIF format: teeny.gif
Vcc >---+--------------+ T1
| 6T )::
\ #28 ):: +-------o HV output
R1 / )::(
47K \ +---+ ::(
/ 2N4401 | ::(
| |/ C ::( 450T
| +--| Q1 ::( #46
| | |\ E ::(
| | | ::(
+--+ +--------+ ::(
| | |17T )::(
C1 _|_ | |#28 ):: +-------o HV return
.001 uF --- | | )::
| +-----------+
| |
Gnd >----+----------+
Two approaches are shown below.
IR radiation falling on the photodiode causes current to flow through R1
to the base of Q1 switching it and LED1 on.
Component values are not critical. Purchase photodiode sensitive to near
IR - 750-900 um or salvage from optocoupler or photosensor. Dead computer
mice, not the furry kind, usually contain IR sensitive photodiodes. For
convenience, use a 9V battery for power. Even a weak one will work fine.
Construct the circuit so that the LED does not illuminate the photodiode!
The detected signal may be monitored across the transistor with an
oscilloscope.
The IR receiver module from a TV, VCR, or purchased from Radio Shack or
elsewhere, drives the base of Q1 through R1. It may even be possible to
eliminate the transistor circuit entirely and connect the LED directly to the
module's output (in series with a current limiting resistor to Vcc or Gnd) but
that depends on the drive capabilities of the module. You can use whatever
Vcc is required for the IR receiver module for the LED circuit as well but may
need to change the value of R2 to limit the current to the LED to less than
its maximum rating.
The specific case where Vcc is +5 V is shown.
These are the type of common triac based light dimmers (e.g., replacements for
standard wall switches) widely available at hardware stores and home centers.
CAUTION: However, note that a dimmer should not be wired to control an
outlet since it would be possible to plug a device into the outlet which
might be incompatible with the dimmer resulting in a safety or fire hazard.
While designed for incandescent or heating loads only, these will generally
work to some extent with universal motors as well as fluorescent lamps down
to about 30 to 50 percent brightness. Long term reliability is unknown for
these non-supported applications.
The first schematic is of a normal (2-way) inexpensive dimmer - in fact this
contains just about the minimal number of components to work at all!
S1 is part of the control assembly which includes R1.
The rheostat, R1, varies the amount of resistance in the RC trigger circuit.
The enables the firing angle of the triac to be adjusted throughout nearly
the entire length of each half cycle of the power line AC waveform. When
fired early in the cycle, the light is bright; when fired late in the cycle,
the light is dimmed. Due to some unavoidable (at least for these cheap
dimmers) interaction between the load and the line, there is some hysteresis
with respect to the dimmest setting: It will be necessary to turn up the
control a little beyond the point where it turns fully off to get the light
to come back on again.
None of the simple 3-way dimmer controls permit totally independent dimming
from multiple locations. With some, a dimmer can be installed at only one
switch location. Fully electronic approaches (e.g., 'X10') using master
programmers and addressable slave modules can be used to control the intensity
of light fixtures or switch appliances on or off from anywhere in the house.
However, for one simple, if inelegant, approach to independent dimming, see
the section: Independent Dimming from Two Locations - Lludge
#3251.
The schematic below is of one that is essentially a normal 3-way switch with
the dimmer in series with the common wire. Only one of these should be
installed in a 3-way circuit. The other switch should be a normal 3-way
type. Otherwise, the setting of the dimmer at one location will always
affect the behavior of the other one (only when the remote dimmer is at its
highest setting - full on - will the local dimmer have a full range and
vice-versa).
Note that the primary difference between this 3-way dimmer schematic and
the normal dimmer schematic shown above is the addition of an SPDT switch -
which is exactly what is in a regular 3-way wall switch. However, this
dimmer also includes a choke (L1) and capacitor (C2) to suppress Radio
Frequency Interference (RFI). Operation is otherwise identical to that
of the simpler circuit.
This type of 3-way dimmer can be used at only one end of a multiple switch
circuit. All the other switches should be conventional 3-way or 4-way types.
Thus, control of brightness is possible only from one location.
Whether this is really useful or not is another story. The wiring would be
as follows:
This one uses a toggle style potentiometer where the up and down positions
operate the switches. Therefore, it has 3 states: Brass to Silver 1 (fully
up), dim between Brass and Silver 1 (intermediate positions), and Brass to
Silver 2 (fully down).
Like the previous circuit, this dimmer also includes a choke (L1) and
capacitor (C3) to suppress Radio Frequency Interference (RFI). It is just
a coincidence (or a matter of cost) that the 3-way dimmers have RFI filters
and the 2-way type shown above does not.
The dimmers can be any normal knob or slide type with an off position.
Note that as drawn, you need 4 wires between switch/dimmer locations.
4-way switches are basically interchange devices - the connections
are either an X as shown or straight across. While not as common as
3-way switches, they are available in your favorite decorator colors.
If using Romex type cable in between the two locations, make sure to tape or
paint the ends of the white wires black to indicate that they may be Hot as
required by Code.
And, yes, such a scheme will meet Code if constructed using proper wiring
techniques.
No, I will not extend this to more than 2 locations!
CAUTION: However, note that a dimmer should not be wired to control an
outlet since it would be possible to plug a device into the outlet which
might be incompatible with the dimmer resulting in a safety or fire hazard.
Apparently, the only real difference between a "toaster oven" and a "toaster
oven/broiler" is that the latter has a means of disabling the bottom heating
element while in oven (non-timed) mode - and, of course, the price!
Well, for toast, at least! :)
Aside from the CMOS IC based toast timer, this is a fairly basic design:
Its conventional counterpart would be identical except using a mechanical
and/or toast temperature sensor in place of the IC timer. Despite what you
might think, the most likely failures are NOT in the 'high-tech' electronics
but the usual burnt out heating element(s), bad cord or plug, broken wires,
and tired switches.
This one is typical of combined all-in-one units using a lead-acid battery
that extends a pair of prongs to directly plug into the wall socket for
charging.
It is a really simple, basic charger. However, after first tracing out the
circuit, I figured only the engineers at First Alert knew what all the diodes
were for - or maybe not :-). But after some reflection and rearrangement of
diodes, it all makes much more sense: C1 limits the current from the AC line
to the bridge rectifier formed by D1 to D4. The diode string, D5 to D8 (in
conjunction with D9) form a poor-man's zener to limit voltage across BT1 to
just over 2 V.
The Series 50 uses a sealed lead-acid battery that looks like a multi-cell
pack but probably is just a funny shaped single cell since its terminal voltage
is only 2 V.
Another model from First Alert, the Series 15 uses a very similar charging
circuit with a Gates Cyclon sealed lead-acid single cell battery, 2 V, 2.5
A-h, about the size of a normal Alkaline D-cell.
WARNING: Like many of these inexpensive rechargeable devices with built-in
charging circuitry, there is NO line isolation. Therefore, all current
carrying parts of the circuit must be insulated from the user - don't go
opening up the case while it is plugged in!
|<------- Charger ---------->|<---------- Flashlight ----------->|
Similar circuits are found in all sorts of inexpensive rechargeable devices.
These have no brains so they trickle charge continuously. Aside from wasting
energy, this may not be good for the longevity of some types of batteries (but
that is another can of worms).
This is another flashlight that uses NiCd batteries. The charger is very
simple - a series capacitor to limit current followed by a bridge rectifier.
There is an added wrinkle which provides a blinking light option in addition
to the usual steady beam. This will also activate automatically should there
be a power failure while the unit is charging if the switch is in the 'blink'
position.
With Sa in the blink position, a simple transistor oscillator pulses the light
with the blink rate of about 1 Hz determined by C2 and R5. Current through R6
keeps the light off if the unit is plugged into a live outlet. (Q1 and Q2 are
equivalent to ECG159 and ECG123AP respectively.)
A coil in the charging base (always plugged in and on) couples to a mating
coil in the hand unit to form a step down transformer. The transistor, Q1,
is used as an oscillator at about 60 kHz which results in much more efficient
energy transfer via the air core coupling than if the system were run at 60
Hz. The amplitude of the oscillations varies with the full wave rectifier 120
Hz unfiltered DC power but the frequency is relatively constant.
For the toothbrush, a 4 position switch selects between Off, Low, Medium, and
High (S1B) and another set of contacts (S1A) also is activated by the same
slide mechanism. The motor is a medium size permanent magnet type with carbon
brushes.
This is an astable multivibrator using discrete parts. Yes, I know, low tech
but you can actually fondle all the internal points of interest that way :-).
The time constant of R1*C1 and R2*C2 determine the blink rate. (Try 50K, 10
uF to start for a visible blink rate).
You can also put an LED in series with one or both of the collector resistors
(to blink alternately) and do away with any additional buffers.
Modify the values of these pair of Rs and Cs for operation at higher or lower
frequencies. Some considerations:
This is a sort of brain teaser since it certainly isn't intuitively obvious
how this circuit works (if it works at all). It may be instructive to start
with the degenerate case of 2 resistors, 2 neon lamps, and a single capacitor.
What happens with that configuration?
(From: Steve Roberts (osteven@akrobiz.com).)
Neons will flash in sequence ABCDE if fed off DC. Momentarily removing the DC
will cause them to flash EDCBA.
>From an ancient Radio Shack "Pbox" kit - the first kit I ever built!
-- end V1.70 --
Super Simple Inverter
This circuit can be used to power a small strobe or fluorescent lamp. It will
generate over 400 VDC from a 12 VDC, 2.5 A power supply or an auto or marine
battery. While size, weight, and efficiency are nothing to write home about -
in fact, they are quite pitiful - all components are readily available (even
from Radio Shack) and construction is very straightforward. No custom coils
or transformers are required. If wired correctly, it will work.
C1 1 uF D2 1N4948 R2
+------||------+ T1 1.2kV PRV 1K 1W
| | +-----|>|-----/\/\---+------o +
| R1 4.7K, 1W | red ||( blk |
+-----/\/\-----+------+ ||( |
| yel )||( +_|_ C2
+ o----------------------------------+ ||( --- 300 uF
| red )||( - | 450 V
| +--------------+ ||( |
| Q1 | ||( blk |
6 to 12 | |/ C +--------------------+------o -
VDC, 2A +----| 2N3055 Stancor P-6134
D1 _|_ |\ E 117 V Primary (blk-blk)
1N4007 /_\ | 6.3 VCT Secondary (red-yel-red)
| |
- o------------+------+
Notes on Super Simple Inverter
| | |
---+--- are connected; ---|--- and ------- are NOT connected.
| | |
AmerTac Fluorescent Lamp Inverter
(From: (Dennis Hawkins (n4mwd@amsat.org).)
Archer Mini Flashlight Fluorescent Lamp Inverter
The circuit below was reverse engineered from the Archer model number 61-3724
mini fluorescent/incandescent flashlight combo (no longer in the Radio Shack
catalog). The entire inverter fits in a space of 1-1/8" x 1" x 3/4". It is
powered by 3 C size Alkaline cells and drives a F4-T5 tube.
o T1
+ o----+----------+----------------+ o
| | ):: +--------------+-+
| \ D 28T )::( | |
| R1 / #26 )::( +|-|+
| 560 \ +---------+ ::( | - |
| / | ::( O 315T | | FL1
| | | o ::( #32 | | F4-T5
| +------|---------+ ::( | - |
| | | )::( +|-|+
+_|_ C1 | | F 28T )::( | |
--- 47 uF | | #32 ):: +--------------+-+
- | 16 V | | +---+
| | | Q1 | O = Output
| | C \| | D = Drive
| C2 _|_ |---+ F = Feedback
| .022 uF --- E /| |
| | | _|_ C3
| | | --- .022 uF
| | | |
o-----+----------+------+-----+
Notes on Archer mini flashlight fluorescent lamp
inverter:
| | |
---+--- are connected; ---|--- and ------- are NOT connected.
| | |
Energizer Mini Flashlight Fluorescent Lamp
Inverter
The circuit below was reverse engineered from the Energizer model number
unknown (worn off) mini fluorescent/incandescent flashlight combo. The entire
inverter fits in a space of 1-1/8" x 1-1/8" x 3/4". It is powered by 4 AA
size Alkaline cells and drives a F4-T5 tube.
o T1 o
+ o----+----------+--------+-------------------+ +----------------+
| | C4 _|_ )::( H 16T #32 |
| \ 1000 --- D 32T ):: +--------------+ |
| R1 / pF | #26 )::( | |
| 360 \ +-------------------+ ::( +|-|+
| / | ::( | - |
| | | o ::( O 160T | | FL1
| +--------|-------------------+ ::( #32 | | F4-T5
| | | )::( | - |
+_|_ C1 | | F 16T )::( +|-|+
--- 47 uF | | #26 )::( | |
- | 16 V | | Q1 +---+ +--------------+-+
| | | MPX9610 |
| | C \| R2 | O = Output
| C2 _|_ |---+---/\/\--- D = Drive
| .047 uF --- E /| | 22 F = Feedback
| | | _|_ C3 H - Heater (filament)
| | | --- .01 uF
| | | |
o-----+----------+--------+-----+
Notes on Energizer Mini Flashlight Fluorescent Lamp
Inverter
| | |
---+--- are connected; ---|--- and ------- are NOT connected.
| | |
Pocket Fluorescent Blacklight Inverter GH-RV-B1
(Schematic from: Axel Kanne (axel.k@swipnet.se).)
4.5 to 12V (4) T1(2)
+ o---+-------------------+---------------+ +-----+-+
| | R2 )::( | |
| +--/\/\--+ W1 )::( +|-|+
| 470 | )::( | - |
+_|_ C1 +-----|------+ ::( W3 | | FL1
--- 47uF |/ C _|_ C3 ::( | | (3)
| 16V +---+------| Q1 --- .015 ::( | - |
| | | (1)|\ E | uF ::( +|-|+
| C2 _|_ | | +------+ ::( | |
| .01uF --- | R1 | | W2 ):: +--+--+-+
| | +--/\/\--|-----|------+ |
| | 20 | | |
- o---+---------+------------+-----+--------------+
Notes on Pocket Fluorescent Blacklight Inverter
GH-RV-B1
| | |
---+--- are connected; ---|--- and ------- are NOT connected.
| | |
Low Power Fluorescent Lamp Inverter 1
The circuit below was reverse engineered from a model number FL-12 'Made
in Hong Kong' battery (8 AA cells) or 12 V wall adapter powered portable
fluorescent lamp. The bulb is an F8-T5.
C2 .01 uF
+------||------+ T1 3
| | +------------+-+
| R1 1.5K | 4 o ::( | |
+-----/\/\-----+------+ ::( +|-|+
| 15T F )::( | - |
| 1 )::( | | FL1
+ o-----+----------|---------------------+ ::( O 350 T | | F8-T5
| | )::( | |
| | 20T D )::( | |
| R2 / 2 )::( | - |
| 68 \ +-------+------+ ::( +|-|+
6 to 12 _|_ C1 / Q1 | | ::( 5 | |
VDC --- 100 uF | | | +---+--------+-+
| 16 V | |/ C | |
| +----| 5609 +---------------+
| C3 _|_ |\ E NPN O = Output
| .027 uF --- | D = Drive
| | | F = Feedback
- o-------+----------+------+
Notes on Low Power Fluorescent Lamp Inverter 1
| | |
---+--- are connected; ---|--- and ------- are NOT connected.
| | |
Gary's EPROM Eraser
(From: Gary Perry (perry_gary@ascom.co.uk).)
I used this circuit based on this design to build an EPROM eraser, using the
4 watt G4T5 germicidal tube.
Low Power Fluorescent Lamp Inverter 2
The circuit below is the type used in inexpensive fluorescent camping lanterns.
In this particular model, an F6-T5 lamp was used. It will drive F4-T5 to
F13-T5 tubes depending on input voltage. The power source can be a 4 to 9 V,
2 A power supply (depending on the size of your lamp) or a suitable battery
pack. This design was reverse engineered from a random commercial unit of
unknown manufacture using a lead-acid battery battery that expired long ago.
o T1
+ o----+---------+-------------------+
| | ):: o C2
| S1 | D 20T ):: +-------||------+-+
| Start |- #26 )::( .022 uF | |
| | )::( 600 V +|-|+
| | +-------+ ::( | - |
| R2 \ | ::( O 250T | |
| 270 / | o ::( #32 | | FL1
| \ +------|-------+ ::( | | T5 lamp
+_|_ C1 | | | F/S 7T )::( | |
--- 100 uF | | | #32 ):: +--------+ | - |
- | 16 V +----|------|---+---+ | +|-|+
| | | | | | |
| | | +-----------------|------+-+
| | +-----------+ |
| S2 | | | | O = Output
| _|_ Off | |/ C | | D = Drive
+-- --+--------+----| Q1 | | F/S = Feedback/starting
| | | |\ E 2SC1826 _|_ D2 |
| \ _|_ | /_\ 1N4007 |
| R1 / D1 /_\ | | |
| 220 \ 1N4148 | | | |
| | | | | |
o-----+-----+--------+------+-----------+---------+
The approximate measured operating parameters are shown in the chart below.
The two values of input current are for starting/running (starting is with
the Start button, S1, depressed.
Lamp type ---> F4-T5 F6-T5 F13-T5
V(in) I(in) I(in) I(in)
-------------------------------------------------------------
3 V .9/.6 A - -
4 V 1.1/.7 A 1.1/.8 A -
5 V 1.3/.8 A 1.2/.9 A -
6 V - 1.4/1.0 A 1.6/.95 A
7 V - - 1.7/1.0 A
8 V - - 1.8/1.2 A
9 V - - 2.1/1.3 A
10 V - - 2.2/1.4 A
Notes on Low Power Fluorescent Lamp Inverter 2
| | |
---+--- are connected; ---|--- and ------- are NOT connected.
| | |
Medium Power Fluorescent Lamp Inverter
This circuit is capable of driving a variety of fluorescent lamps from a 4 to
12 V, 2 to 2.5 A DC power supply, rechargeable battery pack, or auto or marine
battery. With appropriate modifications (if needed) it may be used for other
applications like powering an electronic flash or HeNe laser tube. The
transformer will need to be custom wound (by you) but this is not really
difficult - just slightly time consuming for the 600 turn O (Output) winding
if you don't have a coil winding machine.
The switching frequency is about 21 kHz and varies less than 5 percent over
the range of input voltage for which the bulb remains lit (it is significantly
higher with no load - about 140 kHz). An input voltage of about 4 V is needed
to start oscillation (reducing R1 or increasing R2 would lower this at the
expense of efficiency at higher voltages) but it will continue well below 3 V.
+Vcc o T1
o Q1 +----------------+
| | )::
+ B |/ C )::
L1 ::( +------| MJE3055T ):: C1
24T ::( | |\ E D 15T ):: +----------||---------+-+
#22 ::( | | #26 )::( .0039 uF | |
+ | -_- )::( 600 V +|-|+
| | )::( | - |
+--|-------------------------+ ::( | |
| | )::( | |
| | Q2 _-_ )::( | |
| | | )::( O 600T | | FL1
| | B |/ E D 15T )::( #32 | |
| | ----| MJE3055T #26 )::( | |
| | | |\ C )::( | |
| | | | )::( | |
| | | +----------------+ ::( | - |
| | | ::( +|-|+
| | | o ::( | |
| | -----------------------+ :: +---------------------+-+
| | F 10T )::
| | #32 )::
| | +---------+ :: O = Output
| | | F 10T ):: D = Drive
| | | #32 ):: F = Feedback
| +-------------------------+
| |
| R1 | R2
+----------/\/\/\--+--/\/\/\--+
220 22 _|_
1 W 2 W -
+Vcc o T1
o Q1 +----------------+
| | )::
+ B |/ C ):: C1
L1 ::( +---+----| MJE3055T ):: +----------||---------+-+
24T ::( | __|__ |\ E D 15T )::( .0039 uF | |
#22 ::( | _/_\_ _|_ #26 )::( 600 V +|-|+
+ | _|_ - )::( | - |
| | - D1 1N4148 )::( | |
+--|---------------------------+ ::( | |
| | _-_ D2 1N4148 )::( | |
| | __|__ _-_ )::( O 600T | | FL1
| | _\_/_ | )::( #32 | |
| | | B |/ E D 15T )::( | |
| | +----| MJE3055T #26 )::( | |
| | | |\ C )::( | |
/ | | | )::( | - |
R1 \ | | Q2 +----------------+ ::( +|-|+
1K / | | ::( | |
\ | | o :: +---------------------+-+
| | +-----------------------+ ::
| | F 10T ):: O = Output
| | R2 22, 2 W #32 ):: D = Drive
+--+---------/\/\/\------------+ F = Feedback
Lamp type ---> F13-T5 F20-T12
V(in) I(in) I(in)
---------------------------------------------------
3 V - 1.37 A
4 V 1.76 A 1.52 A (SV)
5 V 1.80 A (SV) 1.60 A
6 V 1.90 A 1.65 A
7 V 1.96 A (FB) 1.70 A
8 V 2.02 A 1.80 A
9 V 2.16 A 1.90 A
10 V 2.33 A 2.05 A
11 V - 2.30 A (FB)
12 V - 2.60 A
Notes on Medium Power Fluorescent Lamp Inverter
| | |
---+--- are connected; ---|--- and ------- are NOT connected.
| | |
Basic 200 W Power Inverter
This circuit was reverse engineered from a Tripp-Lite "Power-Verter" Model
PV200 DC to AC Inverter - typical of those used for camping or boating
applications where the only source of power is an auto or marine battery.
This particular model is rated 200 W continuous. The output is a 60 Hz
squarewave and there is no regulation or precise frequency control. (Unlike
the other circuits in this collection, it is NOT a high frequency inverter.)
3 o
+12 VDC +--------+--------------+
o | | )||
| |/ C +_|_ C1 )||
S F1 20 A +------| Q1 --- 10 uF 31T D )|| o 2
| | |\ E -_|_ 160 V #13 )|| +---------o AC Hot
\ S1 | _|_ - )||(
| Pwr | - )||(
| | 4 )||(
+------+---|--------------------------------+ ||(
| | | _-_ )||(
| | | | )||( O 360T
| | | |/ E _-_ C2 31T D )||( #20
| / | ----| Q2 -_|_ 10 uF #13 )||(
C3 +_|_ R3 \ | | |\ C --- 160 V )||(
10 uF --- 150 / | | | + | 5 )||(
50 V - | 5 W \ | | +--------+--------------+ ||(
| | | | ||( 1
| | | +---------------------+ || +------o AC Neutral
| | | | 6 o ||
+------+---|-------------------+ +-------+ || T1
| | F 17T )||
| R3 2.7 10 W | #24 7 )|| O = Output
| +----/\/\----+------------+ || D = Drive
| |R2 2.7 10 W 10 o || F = Feedback
| +----/\/\-----------------+ ||
| _|_ F 17T )|| (Pin numbers from
| - #24 8 )|| Triplite unit.)
+--------------------------------+
Notes on Basic 200 W Power Inverter
| | |
---+--- are connected; ---|--- and ------- are NOT connected.
| | |
Up to 350 VDC Inverter from 1.5 V Alkaline Cell
Using the basic circuit of the electronic flash unit from a disposable pocket
camera, it is possible to generate any voltage from a few V to 350 V or more
from a 1.5 V AA Alkaline battery. (Similar modifications could be made to
other pocket camera or external flash unit circuits.)
N = 6 * (Vout + 1.2) / 1.2
assuming a small load on the output.
"That sounds about right, rough sums:
After noting that I was impressed that both our numbers work as well as they
do, Tony replied:
V/C2(Fload) = (1.5 - 0.3)26/6 - 1.3 = 3.9V.
"Don't be, it was a pure fluke. The V-drops were only guesstimated and
things like primary IR-drop were not even included."
Well, IR-drop should be negligible - 4 inches of #26 wire is only about .013
ohms :-).
I thought that maybe the relatively long recovery time of the standard-looking
(though unknown markings) diode (D1) is providing enough reverse current to
turn off the transistor. I tested this by subbing both a fast recovery
and high efficiency rectifier - no difference. OK, well maybe just a bit
better performance :-). Perhaps it still is the reverse current spike as the
transistor switches off that drives the base hard to -6 V.
X pF 470 pF
>110 V pulse o-------||-----+------||------+
~200 ns | _|_
o -
~6 V pulse
X of about 26 pF would result in an appropriate divider ratio. However, this
sounds high for the layout and 26 turns. Then again, stranger things have
happened :-). But, a combination of the reverse recovery conduction and
higher capacitance at low voltage as the diode reverses could probably do it.
"You will recall that I was puzzled about energy transfer on the fwd stroke
only. That transformer is going to get stored energy on every fwd stroke,
and yet there appears to be no means of dissipating that energy..... There
is even no protection for the collector of the transistor. In fact, I would
suspect that that is part of the design, in that they did not want the
energy clamped by the primary, they needed it as a high voltage reverse
dissipation in the secondary.
I just wonder how this design came about. The vast majority of these simple
flash inverter circuits use the traditional blocking oscillator topology with
a separate winding or portion of a winding for the base drive/feedback. (At
this point I have taken a look at over a dozen different types.) This
Kodak circuit appears to be unique in letting the high voltage (originally)
winding serve double duty. It probably does save 5 cents in the manufacturing
cost of the transformer by not having to have a separate winding. :-).
"I worked for a chap once (one Jevon Crossthwaite, about 70 now if still
alive) who could take a circuit and absolutely *squeeze* the last ounce of
performance out of it. This is typical of what he would get up to. I did
learn a lot from him, but only partially, because my inbuilt design nature
is still yer brick outhouse.
Strobe Circuits
Strobe Circuits Introduction
Don't forget, there are many more electronic flash and strobe circuits in:
Notes on the
Troubleshooting and Repair of Electronic Flash Units and Strobe Lights and
Design Guidelines, Useful Circuits, and Schematics.
Variable Intensity Variable Frequency Stroboscope
Note that the flashlamp will NOT operate at all intensities for these entire
ranges due to recharge and power dissipation limitations.
Kevin's Strobe Schematics
High power inverter and trigger circuits
Teeny Tiny Inverter Design
IR Detector/Tester Circuits
IR Detector/Tester Circuits Introduction
IR Detector Circuit Using Bare Photodiode
This IR Detector may be used for testing of IR remote controls, CD player
laser diodes, and other low level near IR emitters. It will not have the
sensitivity or dynamic range of the approach described in the section:
IR Detector Circuit Using IR Receiver Module but will
respond to all sources of IR falling within the wavelength range of the
photodiode used since there is not demodulation or coupling circuitry to get
in the way.
Vcc (+9 V) o-------+---------+
| |
| \
/ / R3
\ R1 \ 500
/ 3.3K /
\ __|__
| _\_/_ LED1 Visible LED
__|__ |
IR ----> _/_\_ PD1 +--------o Scope monitor point
Sensor | | (low active)
Photodiode | B |/ C
+-------| Q1 2N3904
| |\ E
\ |
/ R2 +--------o Gnd
\ 27K |
/ |
| |
Gnd o--------+---------+
_|_
-
IR Detector Circuit Using IR Receiver Module
This one uses an entire IR receiver module as the IR sensor. Its sensitivity
and dynamic range will be much better than the circuit described in the
section: IR Detector Circuit Using Bare Photodiode since
these modules have automatic gain control circuitry built in. However, some
modules are tuned to a particular modulation frequency and/or are AC coupled
and will not respond to all remotes or other pulsed or continuous IR sources.
R2
Vcc (+5) o------+-----------/\/\--------+
| 220 __|__
| _\_/_ LED1 Visible LED
| |
|+ +--------o Scope monitor point
+----------+ | (low active)
-| IR |out R1 B |/ C
IR ---> : Receiver |------/\/\-----| Q1 2N3904
-| Module | 10K |\ E
+----------+ |
|- |
Gnd o------+-----------------------+--------o Gnd
_|_
-
Basic Light Dimmer Circuits
Light Dimmer Circuits Introduction
Simplest Dimmer Schematic
Black o--------------------------------+--------+
| |
| | |
R1 \ | |
185 K /<-+ |
\ v CW |
| __|__ TH1
| _\/\_ Q2008LT
+---|>| / | 600 V
| |<|--' |
C1 _|_ Diac |
.1 uF --- (part of |
S1 | TH1) |
Black o------/ ---------------------+-----------+
Types of 3-Way Dimmers
There are at least two varieties of inexpensive 3-way style dimmer switches
which differ mainly in the switch configuration, not the dimmer circuitry.
You will probably have no reliable way of telling them apart without testing
or disassembly.Simple 3-Way Dimmer Schematic 1
Red 1 o--------o
\
S1 o----+------------+-----------+
| | |
Red 2 o--------o | R1 \ ^ CW |
| 220 K /<-+ |
| \ | |
| | | |
| +--+ |
| | |
| R2 / |
C2 _|_ 47 K \ |
.047 uF --- / __|__ TH1
| | _\/\_ SC141B
| +---|>| / | 200 V
| | |<|--' |
| C1 _|_ D1 |
| .062 uF --- Diac |
| | |
| :::::: | |
Black o-----------------+---^^^^^^---+-----------+
L1
40 T #18, 2 layers
1/4" x 1" ferrite core
Simple 3-Way Dimmer Schematic 2
The schematic below is of a 3-way dimmer with a slightly more complex
switching arrangement such that when the local dimmer is set to full on or
full off, it is bypassed. (If you ignore the intermediate dimming range of
the control, it behaves just like a normal 3-way switch.) With this scheme,
it is possible to have dimmers at both locations without the dimmer
circuitry ever being in series and resulting in peculiar behavior.
Location 1 Location 2
3-way Dimmer A 3-way Dimmer +---------+
/o----------------------o\ | Lamp |
Hot o------o/ Silver 1 Silver 2 \o------| or |-----o Neutral
Brass o----------------------o Brass | Fixture |
Silver 2 B Silver 1 +---------+
(If dimming interacts, interchange the A and B wires to the silver screws at
one dimmer).
Br /o---o Br o---o Br/\/o---o
3-way dimmer is up o---o/ S1 or down o---o\ S1 or Dim o---o S1
o---o \o---o o---o
S2 S2 S2
However, it is still not possible to have totally independent control - local
behavior differs based on the setting of the remote dimmer (details left as
an exercise for the reader).
Silver 1 o---+----------------+--------------------+-----------+
| | | |
| | R1 \ ^ Up |
| | 150 K /<-+ |
| | \ | |
| | | | |
| | +---------+--+ |
| | | | |
| C3 _|_ | R2 / |
| --- | 22 K \ |
| | | / __|__ TH1
| | C2 _|_ | _\/\_
| | .047 uF --- +---|>| / | 200 V
Up \ | | | |<|--' |
| | | C1 _|_ D1 |
| | |.047 uF --- Diac |
| | :::: | | |
| Dim o--------+---^^^^---+---------+-----------+
| / L1
Brass o---+---o 12T #18
1/4" x 1/2" ferrite core
Down o
|
Silver 2 o-----------+
Independent Dimming from Two Locations - Kludge
#3251
Here is a scheme which will permit dimming with independent control from two
locations. Each location will have a normal switch and a dimmer knob. The
toggle essentially selects local or remote but like normal 3-way switches, the
actual position depends on the corresponding setting of the other switch:
Location 1 Location 2
+--------+ 4-way SW 3-way SW
Hot o--+---| Dimmer |----o\ /o--------o\ +---------+
| +--------+ / \o----------| Fixture |------o Neutral
| +--o/ \o--------o Center +---------+ Shell
| | (brass) (silver)
| | +--------+
| +------------| Dimmer |--+
| +--------+ |
+---------------------------------------+
As usual, the brass screw on the fixture or outlet should be connected to the
Hot side of the wiring and the silver screw to the Neutral side.
Heating Appliance Schematics
Heating Appliance Introduction
This are only two circuits at present - both for toaster oven/broilers. :)
Typical Toaster Oven/Broiler
Here is a schematic of a typical 'dumb'toaster oven/broiler - one without a
P5-1000 chip if you can believe such a thing exists. :) Most of the
complexity of these simple devices is actually in the sheet metal of the toast
release mechanism! Like the more elaborate unit described in the section:
Toastmaster Toaster Oven/Broiler with Electronic
Controls, there is a knob for control of the oven/broiler functions and
another for toast Light/Dark. A separate lever engages the toast function
which terminates when the toast is done. You will note that other than that
unit having an IC for toast timing, the basic circuits are almost the same.
This diagram is not based on any particular model.
+- - - - - - + - - - - - - - + All part of Oven Control
: : :
S1A S1B _:_ : R1 R2
AC H o--+------/ -----------o o------+---+---:-----/\/\/\/\----/\/\/\/\---+
| Oven Power Thermostat | | : Top Element |
| | | : |
| S2 ___ Toast On | | S1C R3 R4 |
+------------o:o-------------+ +---/ ----/\/\/\/\----/\/\/\/\---+
: | Broil Bottom Element |
+-------+ : R5 / Top Brown |
+-->| Timer |--+ : Toast 47K \ (Full CW) R1-R4: 8-12 ohms |
| +-------+ )|| Release / |
Light/Dark )|| Solenoid | +--+ IL1 Power |
Temp. Sensor + +---|oo|---+ Indicator |
| NE2 +--+ | |
AC N o--------------+---------------------------+-------------------------+
Toastmaster Toaster Oven/Broiler with Electronic
Controls
Rechargeable Appliance Schematics
Rechargeable Appliance Schematics Introduction
Here are circuit diagrams from several inexpensive rechargeable flashlights.
and an electric toothbrush. These all use very 'low-tech' chargers so battery
life may not be as long as possible and energy is used at all times when
plugged into an AC outlet. The electric toothbrush schematic is more
interesting since it uses a high frequency inductive coupling rather than a
direct connection.
First Alert Series 50 Rechargeable Flashlight
2V LB1 Light
1.2A +--+ Bulb S1
+--------|/\|----------o/ o----+
_ F1 R3 D3 | +--+ |
AC o----- _----/\/\---+----|>|--+---|----------------------+ |
Thermal 15 | D2 | | 4A-h | |
Fuse | +--|>|--+ | BT1 - |+ 2V | |
| | D4 +--------------||------|-------+
+----|<|--+ | | | |
| D1 | | D8 D7 D6 D5 | D9 |
+--------+-------+--|<|--+---+--|<|--|<|--|<|--|<|--+--|>|--+
| | |
| / |
_|_ C1 \ R1 |
--- 2.2uf / 100K |
| 250V \ |
| | R2 L1 LED |
AC o---+--------+--------------/\/\-----------|<|------------------+
39K 1W Charging
Black & Decker Spotlighter Type 2 Rechargeable Flashlight
This uses a 3 cell (3.6 V) NiCd pack (about 1 A-h). The charging circuit is
about as simple as it gets!
S1
11.2 VRMS +---------------o/ o----+
AC o-----+ T1 R1 LED1 D1 | +| | | - |
)|| +----/\/\-----|>|---->>----|>|----+---||||||---+ |
)||( 33 Charging 1N4002 | | | | KPR139 |
)||( 2W BT1 | LB1 |
)||( 3.6V, 1 A-h | +--+ |
)|| +-------------------->>------------------------+----|/\|--+
AC o-----+ Light Bulb +--+
I could not open the transformer without dynamite but I made measurements of
open circuit voltage and short circuit current to determine the value of R1.
I assume that R1 is actually at least in part the effective series resistance
of the transformer itself.
Brand Unknown (Made in China) Rechargeable Flashlight
R1 D1 R3 LED1
AC o---/\/\----+----|>|-------+---+---/\/\--|>|--+ D1-D5: 1N4002
33 ~| D2 |+ | 150 |
1/2W +----|<|----+ | | R4 | D5
D3 | | +------/\/\----+--|>|--+
C1 +----|>|----|--+ | 33, 1/2W | LB1 2.4V
1.6uF ~| D4 | | | | | +--+ .5A
AC o--+---||---+----|<|----+--+---|--||||--------------+-+---|/\|----+
| 250V | |- | - | |+ | +--+ |
+--/\/\--+ | | BT1 + C2 - | R5 |
R2 | | 2.4V +---|(----|-----/\/\----+
330K | | | 22uF | 10K |
| | R6 | |/ E |
| +---/\/\---+-+-----| Q1 |
| 15K | |\ C +---------+
| / C327 | | |
| R7 \ PNP | | 1702N |
| 100K / | | NPN |/ C
| \ +---|-------| Q2
| On | | |\ E
| S1 o---------|-----------+ |
+----o->o Off | |
o---------+---------------------+
Blink/Power Fail
Electric Toothbrush with Inductively Coupled Charger
This was found in an Interplak Model PB-12 electric toothbrush but similar
designs are used in other appliances that need to be as tightly sealed as
possible.
E1 CR2 R1 E3
AC o----+----+--|>|-----+---/\/\---+----+----------------+-------+ Coupling
| ~| CR1 |+ 1K | | | ) Coil
+-+-+ +--|<|--+ | | / R2 | ) 200T
RU1 |MOV| CR3 | | C1 _|_ \ 390K | ) #30
+-+-+ +--|>|--|--+ .01uF --- / CR5 | E4 ) 1-1/2"
E2 | | CR4 | 250V | \ MPSA +---|<|---|----+--+
AC o----+----+--|<|--+ | | 44 | | |
~ |- R3 | | Q1 |/ C C3 _|_ _|_ C2
+-----/\/\----+----+----| .1uF --- --- .0033uF
CR1-CR4: 1N4005 | 15K |\ E 250V | | 250V
| R4 | | |
+---------------/\/\------+---------+----+
1K
The battery charger is nothing more than a diode to rectifier the signal
coupled from the charging base. Thus, the battery is on constant trickle
charge as long as the hand unit is set in the base. The battery pack is a
pair of AA NiCd cells, probably about 500 mA-h.
S1B
S1A +--o->o
D1 _|_ | R1,15,2W
+---|>|---+------o o--+ L o---/\/\---+
Coupling | | R2,10,2W |
Coil + _|_ BT1 M o---/\/\---+
120T ( _ 2.4V |
#30 ( ___ .5A-h H o----------+
13/16" + _ |
| | +-------+ |
+---------+--------| Motor |-----------+
+-------+
Miscellaneous Circuits
Discrete Multivibrator
Note: C1 and C2 can be either non-polarized or polarized (electrolytic) types.
If polarized (e.g., to obtain higher capacitance values for lower operating
frequencies), install the capacitors in the direction shown.
Vcc
o
|
+----+-------+--------+----+--------------+
| | | | |
| | | | /
/ / / / \ 220
\ 1K \ R1 \ R2 \ 1K /
/ / / / \
\ \ \ \ __|__
| | | | _\_/_ LED
+--------------+ | | |
| | +--|-----------+ | Q1-Q3: 2N3904 or similar
| | | | | | 10K |/ C general purpose
| | | | | +----/\/\----| Q3 NPN transistor.
C \| | C1 | | C2 | |/ C |\ E
Q1 |--+--)|--+ +--|(--+--| Q2 |
E /| - + + - |\ E _|_
_|_ _|_ -
- -
Question for the student: What happens if one or both Cs are replaced by
resistors?
Simple Pushbutton Clock Circuit
Vcc
o
|
/
\ 10K
/
\
| |\ 74xx14
+----+-----o| >-----> To clock input (positive edge or pulse).
| | |/
2uF _|_ \
--- |
_|_ _|_
- -
Interesting Sequential Neon Flasher
+200V o----+-----+-----+-----+-----+
| | | | |
/ / / / /
\ R1 \ R2 \ R3 \ R4 \ R5 R1-R5: 2.7M
/ / / / /
\ \ \ \ \
| | | | |
+-o A +-o B +-o C +-o D +-o E
| | | | |
| IL1 | IL2 | IL3 | IL4 | IL5 IL1-IL5: NE2
+-+ +-+ +-+ +-+ +-+
|o| |o| |o| |o| |o|
+-+ +-+ +-+ +-+ +-+
| | | | |
Gnd o----+-----+-----+-----+-----+
Connect a .22 uF, 200 V capacitor between each of the following pairs of
points: A to C, A to D, B to D, B to E, C to E.
Circuit to Allow AC Signal to Activate Small Relay
Vcc o--+---+
| |
_|_ )||
1N4002 /_\ )|| Relay coil
| )||
| |
+---+
|
1N4148 5K |/ C
AC o---|>|-----+----/\/\-----| General purpose NPN transistor
+_|_ |\ E
(1-5 VRMS) --- 10uF |
| 15V |
AC +-----------+---------------+
Modify for your needs.
