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DiscoverCircuits.com -- Hobby Corner
Last Updated on:
Friday, December 29, 2017 05:52 AM
Hobby Circuits List
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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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