This interesting 1924 triode tube receiver was found in a documentation by Gernsback. Observe supply voltages. Coils are for tuned wavebands.
In the figure we have two possible configurations for multivibrators with relay. The idea comes...
This circuit serves to isolate analog signals, for example, audio signals in a secure link...
We found this circuit in an old English documentation. Its purpose is to synchronize circuits. The...