Following the American FCC rules, this 90s Radio Electronics circuit shows how to use a transformer to isolate the telephone line from an amplifier circuit.
This circuit is a handset receiver that picks up the signal emitted by a coil under the rug or...
This circuit emits a sound whose frequency depends on the resistance of the circuit under test....
This circuit was found in a 90’s Electronic Engineering. The signal is sinusoidal with the...