Allen-Bradley has been making resistors for a long time. 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, which shows an advertisement from the December 1931 edition of the ARRL's QST magazine. According to Wikipedia: "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. In 1910 the company was renamed the Allen-Bradley Company."
December 1931 QST
Wax nostalgic about and learn from the history of early electronics. See articles
QST, published December 1915 - present. All copyrights hereby acknowledged.
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 motorcar radio.
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 age.
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 curve.
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
ALLEN - BRADLEY RESISTORS
Produced by the makers of Allen - Bradley Control Apparatus