This is a traditional 741 configuration with gain close to 100. We found it in the December 1972 Radio Electronics magazine. The power source must be dual.
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...