This commercial transistor radio was manufactured by RCA in the 1960s. The circuit has only 4 transistors and is powered by a voltage of 9 V with an audio power of 20mW.
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...