This commercial radio with 3 earphone listening transistors was manufactured in Japan in the 1960s. The medium-wave circuit uses germanium transistors and is powered by a 9 V battery.
In this circuit from a 1991 publication, we can use the 2N2646 unijunction transistor and the...
In the figure we have the way to use the transistors of an old-paired pair as a trigger circuit. The...
This static switch or electronic contactor was found in a 1968 Motorola publication. The triac...