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 circuit was found in a Electronics World of 1968. The integrated circuit is the MC1320P from...
The transistor of this remote preamp can be the BC549. We found this circuit in a 1976 technical...
This double-beat oscillator was found in American documentation from the 1970s. FETs admit...