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DiscoverCircuits.com -- Hobby Corner
Last Updated on:
Tuesday, November 29, 2011 08:14 PM
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LED Flasher Circuits
LED Circuits |
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LED Flasher
- Universal 3V Flasher Circuit
designed by David Johnson, P.E. |
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electronic circuit below will flash any LED color with fixed current pulses
powered by a 3v battery. It uses a charge pump approach, which routes a
constant current pulse through the LED, regardless of the LED voltage requirement.
Using this approach, white and blue LEDs, which normally require about 3.6v can be
flashed with a 3v battery. With the component values selected, the LED is
hit with 15ma current pulses lasting about 10ms every two seconds. This
keeps the average current draw from a 3v battery to about 200uA. |
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The circuit relies on a cheap 74HC14
hex Schmitt trigger inverter IC. One inverter forms a pulse generating
oscillator. Other inverters are ganged together to increase the drive current.
A two transistor circuit design forms a constant sinking current controller. See
the schematic below. |
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Click on Drawing Below to view PDF version of Schematic |
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