This circuit was found in a March 1988 Radio Electronics. The voltage scale is set at R3. 19 LEDs are used in this indicator circuit.
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...