Power supply failure alarm 2011-12-29

[3lectrix]

3lectrix submitted a new article:

Power Supply Failure Alarm - Most of the power supply failure indicator circuits need a separate power supply for themselves. Bu

Most of the power supply failure indicator circuits need a separate power supply for themselves. But the alarm circuit presented here needs no additional supply source. It employs an electrolytic capacitor to store adequate charge, to feed power to the alarm circuit which sounds an alarm for a reasonable duration when the supply fails.

Operation

Whenever the supply fails, resistor R1 pulls the base of transistor low and saturates it, turning the buzzer ON.

Schematic...

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[Ziddik]

the electrolytic capacitor must be changed to 25V Or morethan atleast 15V bcoz it is rated to 10v only thus what will happen when u give up 15V power to the circuit? the capacitor will explode for sure.. Pleas post only proper circuits or people may lose their eyes due to the explode of capacitors.. LOL..

 

[3lectrix]

Schematic has been updated. Thanks for pointing that out Ziddik

 

[christianarmand]

Very simple and clever. Well done! I think I'll try with a SUPERCAP!