June 1945 Radio-Craft
[Table of Contents]
Wax nostalgic about and learn from the history of early electronics.
See articles from Radio-Craft,
published 1929 - 1953. All copyrights are hereby acknowledged.
Wafer / stacked / rotary switches
are not found very often in new equipment thanks to the amount of digitization being
used. However, prior to around the 1980s they were present in just about everything
that had selectable functions. Stereo controls for choosing AM, FM, Phonograph,
Auxiliary, Tape, and other types of inputs used wafer switches. Oscilloscope and
other test equipment switches for time base, trigger source, amplitude scale, frequency
band, and x/y and channel input options used them. Tape recorders, televisions and
cameras, washing machines, and many other household items contained one or more
wafer switches. Military, aviation, nautical, and industrial equipment of all sorts
were full of them. Interconnections typically went between layers / tiers / wafers
as part of very complex switching schemes. Here are fairly simple examples of rotary
switch implemented in a
vacuum tube voltmeter (VTVM) and a
transistor tester. Much more complicated wiring schemes can be found on the
Rotary switches are still used, and can be purchased from many
sources, including on Amazon.
Centralab Wafer Selector Switches Ad
Centralab Selector Switches are available
to servicemen and experimenters in kit form ... or standard, completely assembled
and individually cartoned.
Insulation ... either steatite or bakelite.
All switches have double-wipe contact terminals for long life and have a consistently
low contact resistance of less than 2 1/2 milliohms and are completely self-cleaning.
Index is positive with 30° between each rotating position. Switches are also
available for transmitter use.
Send for illustrated Catalog No. 24.
Division of Glove-Union Inc., Milwaukee
Producers of Variable Resistors - Selector Switches - Ceramic Capacitors, Fixed
and Variable - Steatite Insulators - and Button-Type Silver Mica Capacitors.
Posted November 15, 2021