This telephone recording circuit was found in the June 1979 issue of Radio Electronics magazine. The components are common at the time and the power is supplied by the power grid.
This fast circuit for -48 V voltages was found in a 2005 Linear Technology manual. The circuit has a...
We found this circuit in an American publication from the 1990s. The circuit has a Darlington...
In the figure we have an old circuit of a crystal oscillator modulated by an audio signal. The...