Richard Rasker (r.e.rasker@student.utwente.nl) penned:
: In article <4g0r1k$a70@cybernews.cyberus.ca> mthompson@cyberus.ca (Matt Thompson) writes:
: >From: mthompson@cyberus.ca (Matt Thompson)
: >Subject: need simple flashing LED
: >Date: 16 Feb 1996 02:44:04 GMT
: >Can someone tell me how to build a simple cicuit that would envolve the
: >flashing of a LED. I do have some electronics background so I will be
: >able to build it if I have the schematic.
: >Thanks
Try this one:
--------cut here-------
Flasher, uses #1860 bulb,
with Photocell, for Barricade
A Schematic from a real flasher in a
real barricade - by John Lundgren - 9-4-95
Legend: ) = No Connection
+ = Connection
All resistors are 1/4 W 5%.
P1
/--\ silicon photocell (turns it off during daytime)
+------( @ )----+
| \--/ |
| |
| R1 75 k | R2 2.2 k
+------/\/\/\----+------/\/\/\----------+
| | |
| +----------)----------------------+
| | | R3 160 k |
| | NPN | +----/\/\/\----+
| | TO-92 | |
| | | |
| | ======= | R4 R5
| | E / \ | 2.7 k 5.6 k
+-----)---- / \--+--/\/\/\------+----/\/\/\----+
| | | |
| | C1 10 uF 16V tant. | |
| | || + | |
| +------||-------+ | |
| || | | |
| | | PNP |
| | | TO-92 |
| | ======= |
| /---\ | / \ E |
+--------( @ )------+------------/ \---------+
| \---/ |
| I1 # 1860 lamp |
| |
| |
| |
O - 6 VDC (2 lantern cells in parallel) + O
C1 10 uF 16V tantalum electrolytic (determines flash rate)
Q1 2N3904 NPN gen'l purp. transistor
Q2 2N2907 or PN2907 PNP audio gen'l purp transistor
P1 Silicon photocell (looks like a LED)
I1 #1860 lamp 6V, low current
R1 75K 5% 1/4W
R2 2.2K 5% 1/4W
R3 160K 5% 1/4W
R4 2.7k 5% 1/4W
R5 5.6K 5% 1/4W
--------cut here-------------
Also try Filip G's web page. It's at "http://www.paranoia.com/~filipg"
where there are circuits for the LM3909 flasher chip. Also, try other
links to other sites/pages.
: The very simplest is to buy a flashing LED; they come in all normal LED
: colors, and have supply voltages of 5 and 12 V. Price (here): about $1.50.
: If you want to build a flashing circuit yourself, you can use a variety of
: devices and circuits; the simplest is the LM3909 which uses 1 external
: capacitor to flash a LED on just a 1.5V battery. Also widely used: NE555 or
: ICM7555 circuits where the 7555 is the CMOS version of the NE555. If you want
: to make 6 LED's flash independently with just one IC you can use a CMOS 40106
: (hex Schmitt-trigger/inverter) and a handful of capacitors & resistors.
: Success,
: Richard
: Richard Rasker
: Calslaan 54-11
: 7522 MG Enschede
: Holland
: tel. +31-(0)53-4350834
--
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| John Lundgren - Elec Tech - Info Tech Svcs. | jlundgre@delta1 |
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Date: 18 Feb 1996 01:26:35 GMT
Original Subject: Re: need simple flashing LED