This circuit is from a 1968 Electronic Design. The circuit uses transistors of the time that can be replaced with modern equivalents. More stages can be used to get higher tension.
The sensor for this alarm is an LDR and it consists of an oscillator that goes into action when...
We found this amplifier circuit for inductive audio pickups in a documentation from the 70s. The...
This circuit is from an American documentation from 1976. The FET can be the BF245 or MPF102 and...