This primitive solar radio was found in a Gernsback publication from 1960. The transistor is made of germanium of the time and the earphone is magnetic with high impedance.
This stage of IF to 455 kHz operates with voltages from 1.5 V. We find it in a 90s Popular...
This trigger circuit with transistors, which may be 2N2222, was found in a 1967 publication. The...
We found this thyristor power supply in a 1987 documentation. It uses common SCRs as rectifiers and...