Found in a 1924 publication, this 2-valve receiver has a speaker output. Power comes from several batteries. Information about the coils is given.
This circuit is an improvement of the previous circuit. An input resistor must be included...
This low frequency astable multivibrator use two probes in the simulation. The probes ar found in...
This circuit, suggested by a 1975 documentation, detects an electrical discharge in a storm by...