This 4-channel mixer amplifier was found in an American publication from 1947. The circuit uses counterphase output tubes and a transformer power source.
We found this version of the siren that makes the American police siren sound in a 1980...
This microphone circuit was found in a collection of American 80's layouts, using operational...
The integrated circuit used in this filter is like to a double 741 and must be powered by a...