This circuit is from an old Japanese publication of 1962. The circuit uses two batteries, one for the filaments of the tubes and the other one of high voltage for the plate circuits.
This circuit converts pulse frequency to current, which is indicated on an analog instrument. The...
The microphone of this short-range MW transmitter should be low impedance magnetic (a small...
This microtransmitter operates at a frequency between 3.5 MHz and 10 MHz determined by the...