This battery-powered 3-valve circuit was found in American documentation from 1947; Two batteries are used, one high voltage and one low voltage for the filaments.
This circuit, with adjusted sensitivity, can use common general-purpose transistors. The circuit is...
This circuit was found in a 1967 RCA documentation. The semiconductor components are from the...
This is the traditional configuration of na Astable Multivibrator using two NPN ttransistor....