We found this circuit in the 1977 RCA Solid State ICs. The circuit consists of a current amplifier with a gain of 1000. The supply must be made from a symmetrical source.
We found this source with the CI 723, common at the time, in a 1989 paper. Power transistors must be...
Often, unauthorized people use the phone to make improper calls. A control for this is achieved with...
Found in an 80's documentation this circuit uses an integrated from the uncommon era today. Other...