This circuit was obtained in a 1967’s EEE. Transistors and integrated circuits can be replaced by modern equivalents. The FET is for general use.
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...