Found in a 90's EDN, this circuit provides a current of a few tens of mA. The circuit can generate 15 V from a 5 V input.
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...