This circuit makes use of an optical coupler to isolate the telephone line. The circuit is from 1970s documentation. The components admit equivalents.
This is the simulation of a Ultrasound Receiver using the 741 IC, an operational amplifier....
This car amplifier was found in the 1982 SGS Linear Integrated Circuits manual. The circuit can be...
The circuit shown in the figure activates a small indicator lamp that will start to flash when the...