This circuit was found in Raytheon's 1967 documentation. The circuit uses an operating of the era, but the configuration can be applied to modern operational amplifiers.
This circuit, from the 90's, is intended for operation with vinyl record players of the time, as...
Using a zener diode it is possible to change the linearity of the scale of an analog instrument by...
Found in American documentation from the 1980s, this circuit prolongs the ringing of a doorbell or chime...