This is an amplifier circuit intended for modulating transmitters. The 5-tube circuit is from an American manual from 1947. The power supply uses a transformer.
In the figure we have an interface using an optical coupler and the comparator LM339 or any...
This circuit for cars with mechanical breakers (contact breakers) was found in the April 1969...
This circuit can be used to show the direction of current flow in semiconductors, such as LEDs....