This elementary receiver with a crystal earphone was found in Japanese documentation from the 1960s. The coil has 60 + 40 turns of wire 28 to 32 in a ferrite rod.
We find this circuit in an 80's EDN. The circuit can be used with equivalent operational,...
This full-wave circuit was obtained in Motorola's 1974 unijunction transistors manual. The circuit...
This circuit was found in Motorola documentation from 1966. The lamps are according to power and...