Based on the MC1488 or MC1489 operational amplifiers, this circuit has a 5000V isolation driving a 2N3055 transistor for a high-power signal. The receiver is a common phototransistor.
The transistors are 2N918, 2N3464 and other RF equivalents of the time for Q1. For Q2, 2N3399, 2N2894...
This circuit, which can be used as a shield, was found in a 90s Electronic Design. The circuit...
This interesting intercom circuit was obtained from an Argentine publication from the 1970s....