Featured in the February 1949 Radio Electronics magazine, this benchtop instrument generates multi-range audio signals. The circuit has 6 tubes including the rectifier.
This old circuit (1968) uses a germanium transistor to drive a relazy from a switch. The circuit...
The basic integrated circuits of this 1988 multimeter are no longer very common today, but if...
This 50 kHz to 250 W circuit was found in an old RCA documentation. The transformer is a...