This receiver is from a 1924 Gernsback publication. The receiver has good efficiency when powered by the indicated voltages. Listening is through a high-impedance phone.
The diagram below is an application of the Texas Instruments TPS25221 to an ISM controlled power...
The OC30 power transistor is an old type of germanium from the 60s. This amplifier, using this...
This circuit was found in a 1973s Japanese publication. The power transistors used are of the era...