This circuit divides the grid 60 Hz frequency to obtain 20 Hz to drive mechanical watches used at the time. The circuit is from a 1970 CQ magazine.
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...