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This circuit is from a publication in 1972, originally made with germanium transistors, but can be...
This circuit is from an April 2000 Poptronics. The magazine no longer exists, but the circuit can...
The circuit shown in the figure is suggested by Maxim (www.maxim-ic.com) and makes use of the...