This simple continuity tester, whose configuration can be found several times on this site, is powered by only 2 batteries providing the indication on an LED.
The project that we present below is very interesting, serving to identify remote calls such as in...
This circuit was found in a Dutch documentation from 1970. The circuit makes use of semiconductors that...
This amplifier with an OTA has a gain of 40 dB. The power supply must be symmetrical. Found in...