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 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...