This circuit is from a 1968 documentation using one of the first integrated circuits available at the time, the TAA370. The circuit is powered by 1.3 V using a 200 ohm handset.
We found this common application of the 741 operational amplifier in a 1977 documentation. The...
This circuit, found in an old 1967 publication, cuts the current from a source when the current...
This LED bar graph circuit was found in the October 1980 issue of Radio Electronics magazine. The...