This transmitter for the 3.5 and 7 MHz ham radio was found in a 1950s Japan publication. No information was given on the coils and the power supply.
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...