This circuit with RIAA equalization is from 1985 US documentation. The circuit has a flat response of 150 Hz to 40 kHz. The power supply must be symmetrical.
This simple inverter was found in a 1997 documentation. Its purpose is to apply a high voltage to a...
For this circuit, the polarity of the power input does not matter, as the output terminals will...
In the figure we have the way to control an SCR with a programmable unijunction transistor (PUT)....