This traditional circuit generates a 200 Hz sinusoidal signal. The frequency depends on the capacitors and the transistor can be a BC548. We found this circuit in a 1979 documentation.
Found in an English publication from 1967, this circuit generates 5 kHz signals with harmonics that...
This preamplifier circuit for turntable cartridges was found in the March 1994 issue of...
This circuit is from documentation from the 80s, so it makes use of an operational amplifier that...