This RF amplifier step has a dynamic range of 140 dB and can amplify signals from 0.5 to 40 MHz. FET is old, but modern equivalents can be used.
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...