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.
Found in a PE Hobbyst Handbook, this circuit checks if there is voltage in a power outlet by...
Here is a high-quality intercom for demanding readers. The circuit is from a 1982 documentation. Of course,...
This circuit shows how to use a low current read switch to control high power loads. The circuit...