This receiver is from a 1924 Gernsback publication. The receiver has good efficiency when powered by the indicated voltages. Listening is through a high-impedance phone.
This circuit was found in a 2005 Linear Technology manual. It senses the two-way current,...
This circuit was found in an Electronics Now from the 90's. See the previous article for the...
This is the basic configuration of a monostable TTL with the 74121. The trip is done with an NC...