> Could someone tell me how to make a simple flashing LED circuit please?
> thanks
> PS: Is there a FAQ for this group?
Something like this will work with just about any two transistors
(one NPN and one PNP). If the LED never lights, reduce the value of R1.
If the LED stays on, increase the value of R1. To run at a lower voltage,
or higher brightness, reduce R3. To increase the LED on time, increase R2
or C. Use a low leakage capacitor. Tantalums work well, electrolytics
may leak too much.
Bill
+12 +12
| |
| |
\ |
*R1 / 5.6 Meg |
\ / E
/ B |/
| +--------------------- | PNP (2N3906)
| / C |\
| B |/ \ C
+---| NPN (2N3904) |
| |\ |
| \ E |
| | - + |
+------ | ----||---/\/\/\/--------+
| C R2 |
| 0.33uf 82K \
| / R3= 680 Ohms
| \
| |
GND __V__ LED
|
|
GND
Date: 6 Nov 1995 03:49:28 -0500
Original Subject: Re: Flashing LED?