This circuit was found in the September 1984 issue of Radio Electronics magazine. The circuit is based on a 555 and a MOSFET consisting of a flasher that controls a buzzer.
We found this circuit in an old documentation. The instrument can be an ordinary multimeter in the...
This simple electroscope with bipolar transistors is not the most sensitive, but can detect static...
This circuit was found in an old Popular Electronics. It causes an LED to pulse and, at the same...