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
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
articles are scanned and OCRed from old editions of the ARRL's QST magazine. Here is a list
of the QST articles I have already posted. All copyrights are 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
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.
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
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.
Greenfield Avenue, Milwaukee, Wisconsin
ALLEN - BRADLEY RESISTORS
Produced by the makers of Allen - Bradley Control Apparatus