Using 4 tubes, this 1924 receiver combines new technologies as an intermediate frequency stage that was already beginning to appear. Listening is via phone and battery power.
We found this circuit in a 1982 documentation. An intercom to be good must be sensitive and have...
With an optical coupler and a power transistor, which can be the BD135, it is possible to control...
The Variable Frequency Oscillator (VFO) shown in the figure can generate signals in a frequency range...