The 1: 1 transformer on this circuit found in a 1967 Electronics World can be wrapped around a small ferrite rod. The circuit operates with 600 to 6 000 Hz control signals.
This circuit was found in the September 1974 issue of Radio Electronics magazine. The circuit uses...
This circuit was found in the December 1983 issue of Radio Electronics magazine. The sensor is an...
We found this circuit in a 1975 publication. The circuit can be made with more modern equivalent...