This circuit is from an old Japanese publication of 1962. The circuit uses two batteries, one for the filaments of the tubes and the other one of high voltage for the plate circuits.
This circuit uses a common multimeter on the voltage scale to measure the beta gain of a...
This simple optical alarm circuit was found in the 1991 Electronics Experimenter Handbook. The...
This circuit uses an audio output transformer found in old transistor radios. Power output is...