This low noise microphone preamplifier circuit was found in American documentation from the 90s. The circuit requires special care with the layout. The power can be between 9 and 18 V.
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...