This circuit is from Radio Electronics from March 1985. The circuit uses common components at the time and LEDs as indicators. The power supply is 9V.
This variable power supply circuit was found in a German publication from the 1980s. The circuit is...
This circuit is suggested by Texas Instruments and is based on a relaxation oscillator with...
In the figure we have a typical Wien Bridge oscillator with AGC. The negative waveform is sampled by...