Crystal variable oscillator (CB9506E)

Found in Radio Electronics from the 90s, this circuit can vary the frequency in small values around the crystal frequency.

Linear Amplitude Modulator (CB21087E)
Found in an Analog Devices documentation from the 90s, this circuit uses a component of the time,...
Tachometer with feedback control (CB9350E)
This circuit was found in Philips documentation from 1965. No information was given about the...
Symmetrical power supply with separate outputs (CB25955E)
This circuit was found in the June 1990 issue of Radio Electronics magazine. Integrated circuits must...