Other versions exist on this site from various publications. This one is from the Radio Electronics Experimenter from 1990. The bargraph circuit uses the UAA170.
This solid-state relay (SSR) or shield was found in a 1995 Electronics Now. The transistor can be...
The components used in this National Semiconductor circuit are not common today, but the...
The circuit presented in the figure is an amplifier for stereo sources with the Maxim MAX9723...