This crystal or galena radio was found in documentation from the 1990s. The earpiece must be a high impedance crystal or magnetic earpiece and D1 can be any germanium diode.
The circuit shown in figure 1 consists of an Inverter Module for CCFL Lamp that can be supplied with...
This circuit is the power supply for the amplifier in the previous circuit. The transformer is 5 A...
This circuit serves as a reference for the components used and the time. The circuit is from 1967...