This circuit transmits the audio signals from a telephone line to an FM receiver placed nearby. The coil has 4 turns of wire 28 in the form of 1 cm without core. The trimmer is 2-20pF or greater.
This circuit using an operational amplifier was found in old American documentation. It can be...
If the circuit oscillates, emitting sound, it is because the transistor is good. This simple...
Like the previous circuit, this is used in the analog part of the telephone lines. The same...