The Capacity Operated Relay is a device that can be used as an electronic switch to activate a variety of things. The novel part of the device is that it is operated by a hand approaching or moving away from an antenna attached to the device without actually touching it. In the middle part of […]

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Editor’s Notes: This is a construction project for a “Capacitance Operated Relay” (a.k.a Capacity Operated Relay) from the “Electronic Hobbyists’ Handbook” by Rufus P. Turner, first published in 1958. (Library of Congress Catalog Card No. 57-9010) (Information obtained from the United States Copyright Office indicates this book  is no longer under copyright.) I have added […]

A simple spreadsheet program displays a graph of IF frequency error for selected values of tuning capacitors, ant. and osc. inductors, and various values for the trimmer and padder capacitors.

Photos of an unbuilt Heathkit XR-1L six-transistor radio from around 1958.

The Philmore TR-22 was a transistor radio kit sold around 1958.