Found in a 1960s documentation, this circuit uses a transistor to drive a relay as well as a set of neon lamps with high voltage power supply.
This simple electroscope with bipolar transistors is not the most sensitive, but can detect static...
This oscillator for various frequencies was obtained from a 1980s telecom documentation. The...
This circuit is from a July 1970 Radio Electronics magazine. The sensors are metal probes. The 18 V...