Power Failure Alarm (CB25348E)

This circuit triggers an alarm when the mains power is cut off. The circuit was found in the July 1990 issue of Radio Electronics magazine.

| Clique na imagem para ampliar |

4W x 500kHz transmitter (CB21803E)
We found this 4W transmitter in a Mullard transistor manual from 1960. The circuit is powered by...
Treble Booster (CB12010E)
The response curve of this circuit has a maximum boost of around 6 kHz. The vertical scale is in...
Audible Indicator for Car (CB26291E)
Using the 555 this circuit was found in a Popular Electronics from the 90's. The circuit directly...