This circuit was found in old American documentation. Transistor is general purpose and coil rated is for 1.5 MHz. Wind 50 + 50 turns of wire 28 onto ferrite rod for 1 MHz.
This sensor was published in Radio Electronics magazine in April 1962. The two-transistor circuit...
Another of the many similar configurations we have in this section. This one is from a Radio...
This circuit like the previous one is intended for 24V x 3W solenoids being connected from the...