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 source for devices for automotive use was found in a 1985 documentation. The power...
This circuit trips when the voltage set in the pot is exceeded. The tone depends on C3 and...
The circuit shown is from the 1977 GE semiconductor manual. The circuit uses a controlled silicon...