This interesting circuit uses a sodion valve that we have already described in an article on the website. The circuit uses several batteries for power. The phone is of high impedance.
In the figure we have the way to use the transistors of an old-paired pair as a trigger circuit. The...
We found this synchrodyne receiver for the medium or short-wave band in the Radio Electronics...
This old circuit, from a 1992 documentation, was used with tape recorders acting as playback. The...