This is the circuit of a commercial radio sold in Japan in the 1960s. The IF is 455 kHz, and the supply is made with a voltage of 9 V. The radio receives stations in the medium wave range.
This amplifier for hearing aid was found in a 1968 documentation using an integrated of the time....
We obtained this circuit from a 1993 documentation. The circuit has 9 current ranges that are...
In the figure we have the transmitter of a data transmission system with optical fiber suggested by...