This circuit was found in the December 1982 Radio Electronics magazine. The components are of types that are still commonly found. The power supply is not included.
This simple Bargraph photometer with 4 LEDs was found in a 1997 documentation. The scale is...
This 7400 TTL circuit has a memory, keeping the LED on when a pulse is detected. The circuit must be...
This constant current source was found in the Linear Applications Handbook of the National...