Eco-Friendly Power-On Indication

Posted on July 8, 2010 by Rend
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This is a power on circuit that works temporarily only when the power is turned on, this  LED illuminates for a few seconds, then turns off again.   This design is eco-friendly since it consumes only a little power at the beginning of the power connection. Here is the schematic diagram of the circuit:

POWER ON

The circuit uses the 47uF capacitor that is charged to drive the transistor base when the circuit is powered. It will be discharged when the circuit is turned off, so it will be charged again to drive the transistor if the circuit is powered again.

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