This circuit was found in a 1977 documentation. It limits the voltage from a source using zener diodes on the rectifier bridge. It is an unusual configuration today.
This proximity relay circuit was found in the July 1990 Radio Electronics magazine. The supply...
This circuit is from an old operational amplifiers manual. However, the setting applies to modern...
Using an operational amplifier, the figure shows how to convert the waveform to low frequency...