This circuit was found in a Dutch documentation from 1970. The circuit makes use of semiconductors that have current equivalents and is indicated by a 0-5 mA milliammeter.
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...