This circuit uses an HA2400 consisting of 4 digitally controlled operational amplifiers. The circuit is from a Radio Electronics magazine from March 1980. The power supply must be symmetrical.
This useful inductance bridge was found in a Radio Electronics from September 1963. The...
This circuit uses a 7-segment display to indicate the logic level of a test circuit. The power...
Powered by voltages from 6 to 12 V, this circuit from a Popular Electronics from the 90s,...