This third-order filter was found in a 1975 publication. The circuit must be powered by a symmetrical source. The components can be changed for operation on other frequencies.
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...