This is a Japanese commercial radio from the 60s. The superheterodyne circuit of 7 transistors for medium waves has 200mW of output when powered by 4 common batteries.
This circuit for controlling high power in the AC network was found in a Motorola documentation from 1968....
Found in American documentation from the 90's, this circuit consists of a solid state relay with...
This oscillator uses a small transistor amplifier or radio output transformer. We found it in a...