This circuit was found in the July 1978 issue of Radio Electronics magazine. The circuit uses a common digital voltmeter as the indicator. The sensors are integrated circuits of the time.
This traditional metronome configuration uses unusual transistors in the original version, but it...
This circuit was found in Texas Instruments documentation from 1968. The transistors are from that...
This sensitive field strength meter was found in 1993 documentation. The instrument may be the...