This circuit was found in an American publication in 1966. The circuit uses a general-purpose FET that admits an equivalent. The instrument is a 250 uA full-scale microammeter.
Suggested by an American documentation for 1969 neon lamps, this circuit provides SCR control with...
This circuit was obtained in a 1976 amateur radio manual. The circuit can be made with a 2N2222...
This circuit was taken from the 1974 Ferranti transistor manual. It is intended to use a common...