This circuit is from a 1974 publication by Motorola. The unijunction may be 2N2646 and bipolar BC558 and BC548. The pulse duration depends on the capacitor.
This circuit for VCR recording heads was found in the February 1990 issue of Radio Electronics magazine....
This very simple continuity tester uses a small 1.5 V lamp (type used in flashlights). Can be...
This commercial radio with 3 earphone listening transistors was manufactured in Japan in the...