Written in an article in Radio Electronics magazine in April 1987, this circuit triggers an alarm via a relay. Details of the sensor are given in the article.
This project was found in a documentation from 1980. It is a central of sound effects, a simple...
This amplifier for public address was found in English documentation from 1967. The transistors are from...
This circuit was found in an English magazine from 1978, but it is still current, just change the...