This circuit provides a 5 V negative voltage from a positive input voltage. Found in old American documentation, information on the used integrated circuit was not provided. Probably an oscillator.
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...