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 3-decade operating range VCO was found in a 90s Popular Electronics. The circuit uses...
This circuit was found in Linear Technology documentation from the 90's. The circuit uses...
We found this circuit in a Motorola publication from the 70s. The circuit can be implemented with...