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 for cars with mechanical ignition systems was found in the Electronics Experimenter handbook...
This code practice circuit was found in a 1990s issue of Radio Amaterur Today magazine. It...
The circuit presented was found in the Linear Applications Handbook of the National Semiconductoir of 1994....