December 1931 QST
Wax nostalgic about and learn from the history of early electronics. See articles
QST, published December 1915 - present (visit ARRL
for info). All copyrights hereby acknowledged.
Allen-Bradley has been making resistors for
a long time, as evidenced by this advertisement from the December 1931 edition of
the ARRL's QST magazine. From my earliest days in electronics in the 1970s,
I remember using their products in hobby projects and then later in professional
applications. Rockwell Automation now owns
Allen-Bradley, so if you want historical information, you will
have to do a search for pages like this one. According to
"The company was initially founded as the Compression Rheostat Company by Dr. Stanton
Allen and Lynde Bradley with an initial investment of $1,000 in 1903 ($26,838
in 2021 money wrt 1913). In 1910 the
company was renamed the Allen-Bradley Company."
Allen-Bradley Resistors Advertisement
Allen Bradley Resistors Advertisement in December 1931 QST Magazine
Here is the text of the advertisement:
Stop Interference on Radio-Equipped Cars With Bradley Suppressors
No Shielded Ignition Cable Needed
Bradley Suppressors are special solid molded resistors used by prominent car
manufacturers to provide individual resistors for each spark plug and for the common
cable to the distributor on radio-equipped can.
They increase the resistance of the high tension ignition system and minimize
the disturbing oscillations in the ignition circuit which interfere with the radio
receiver in the car. When used with suitable bypass condensers in other parts of
the circuit, shielded ignition cables are unnecessary.
They do not affect the operation of the motor. The sturdy construction of Bradley
Suppressors adapts them for the severe service in which they are used. Heat and
moisture and age have no effect upon their performance. They are the last word for
The Bradleyometer is a potentiometer with approximately fifty solid resistance
discs interleaved between metal discs.
Bradleyunits are solid molded resistors unaffected by temperature, moisture or
Their accurate calibration, great mechanical strength and performance make them
ideal for providing correct C−bias, plate voltage, screen grid voltage and for use
as grid-leaks and as fixed resistors in resistance-coupled circuits.
All units are color-coded to meet any radio set manufacturer's specifications.
The total number of discs can be arranged in accordance with any resistance-rotation
One or more Bradleyometers can be arranged to operate with one knob. Mixer controls,
T-pad and H-pad attenuators and other complex controls can be provided.
ALLEN - BRADLEY CO.
106 W. Greenfield Avenue, Milwaukee, Wisconsin
- BRADLEY RESISTORS
Produced by the makers of Allen - Bradley Control Apparatus
Posted April 7, 2021
(updated from original post on 12/18/2012)