We found this circuit in an old documentation for radio amateurs. The circuit uses an analog indicator. The characteristics of the coils are given next to the diagram.
This control circuit up to 1 kW was found in a 1967 RCA documentation. The components are from...
We found this circuit in an Analog Devices documentation from the 1990s. It provides an...
In this circuit the signal from the phototransistor is amplified by a Darlington stage and then...