The integrated circuit used in this 2002 project is not very common. It is powered directly by the telephone line, requiring no power supply.
This simple transmitter for the AM range was found in a Popular Electronics magazine from March...
This circuit was found in a 1968s American. Transistors are of general purpose and the input is a...
This circuit with SCR was found in an old documentation. The SCR can be the TIC106, and the...