This sensitive 4-tube, battery-powered receiver was found in a 1949 Radio Electronics. The circuitry was wired in crystal earphones.
The circuit in the figure is suggested by ST Microelectronics (www.st.com) and consists of a...
The transistors of this circuit may be the BC548 or BC549 and its power supply can be performed...
This circuit is from Mullard's transistor reference manual from 1960. The circuit will also work...