This is a very simple circuit I designed.It gives out a sharp alarm(LED lights up for a second) when the switch breaks open(to indicate the power is down).
The problems be:
1.It consumes 3mA continuously when the power is up.This energy is wasted,though not a lot,can it be eliminated?
2.There is a voltage drop on the transistor between the capacitor and the led,so this circuit won't work with a 3V LED or a 3V buzzer.
3.How can I make the LED light up longer without using a battery or a super capacitor?
