Found in a 1947 publication, this 7-tube amplifier uses four tubes in the output stage. The circuit uses a power source with a transformer.
In the figure we have a circuit that allows to increase the maximum current from a 78xx to more...
This audio millivoltmeter was found in a 1992 publication. It can still be assembled, as the...
This circuit is indicated to determine the flight time of an electric motor model airplane. The...