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How to make a bi colour LED flasher? Answered

Hi guys 
I need ur help I want to make a bi colour  LED flasher for about 40 LEDs or less or more powered by a 9v battery If any one has an idea of the circuit used pleas help 

2 Replies

iceng (author)2012-10-01
frollard (author)2012-10-01

You'll have a hard time powering 40 leds from a 9v for very long.

At most efficient, 40 leds @20mA and 2-4 volts will be .06watts each is 2.4 watts...

'typical' 9 Volt 500mAh total 15mA drain (0.135 watts)

...So you're going to draw 2.4 watts from something that can reasonably drive 0.14 watts. It simply won't happen, and it will be dead within 10 minutes.

9 volts @ 3 watts is easy to source from 6 AA or C or D batteries, and will last a LONG time compared to a simple 9v battery. AA holders are cheap, consider one.

a 2 colour led flasher is super easy, and can be done any of a hundred ways; the simplest is the 2-transistor flasher.
Trouble is, it only flashes one or a few leds...not 40.

Next is the 555 timer flasher, and any of the hundreds of derivatives.
*The above is designed for 6 volts, 4 AA batteries...

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