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.
The critical components of this 1978 circuit are transformers, which, hopefully, can be obtained from...
This circuit was found in a 1995 documentation, consisting of a car protection system that blocks...
Suitable for dual applications, this timer was found in a 90s Popular Electronics. The circuit...