42 kHz oscillator (CB21805E)

This circuit was used as an eraser for old tape recorders. The circuit is from a 1960 Mullard transistor manual.

Voltage to Frequency Converter with Potentiometer (CB25385E)
We found this circuit in the June 1991 issue of Radio Electronics magazine. The circuit can be...
Voltage divider (CB21650E)
This precision circuit, which also functions as a bridge, was found in a February 1967 Popular...
Wavemeter (CB15830E)
We found this circuit in an old documentation from the 70s. The text is the original one of the...