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, found in a 1986 documentation, uses an optical sensor to count pulses and, in its...
This different alarm system, found in an old publication, uses the starter chain to protect the...
This circuit was obtained from an American publication of the 80's. The integrated circuit is of the...