This circuit fires with the noise captured by the touch of a sensor. Signal shapes are given next to the diagram. The circuit is from the 80s, using components from that time.
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...