This bargraph circuit using LM3914 was found in the October 1980 Radio Electronics magazine. Note the use of a transistor to modify the response.
Found in a 90’s Popular Electronics, this circuit applies to almost any operational amplifier. With...
This circuit is suitable for calibrating old oscilloscopes. It was found in a 1980s documentation. It...
We found this circuit in the April 1979 Radio Electronics magazine. Note the filter capacitor bank...