This circuit generates frequencies determined by R3 and C1. We found it in the Radio Electronics magazine of May 1988. The power supply must be symmetrical.
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...