An Improved Ohm-meter or Apparatus for Directly Indicating Resistances.
Year: 1899

page_text: COMPLETE SPECIFICATION.
An Improved Ohm-meter or Apparatus for Directly Indicating
Resistances.
I, CHARLES BEEZ, of 6, Kirchenstrasse, Frankfort on Maine, Germany, Engineer,
do hereby declare the nature of this invention and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement:
This invention relates to the measurement of electrical resistances and consists
in a new combination comprising a controlling resistance, a compensating or
comparing resistance, a battery or similar source of electrical current, and a
sensitive galvanometer, whereby the amount of a resistance placed in the same
circuit therewith, may be directly read off.
Referring to the accompanying drawing which illustrates diagrammatically
one method of carrying the invention into effect a controlling resistance a
compensating resistance and a sensitive galvanometer g are placed in series
with a battery 6, or other source of constant current. The resistance r is arranged
to be cut of circuit as desired by a key or like devices and the resistance to be
measured is placed between two terminals, a
The galvanometer is preferably so arranged that the total deflection of the
needle corresponds to a current strength of 6 milliampères. When the circuit
is closed through a fixed resistance P of 1000 ohms the arm of the controlling
resistance is regulated till the galvanometer indicates 1000 on the scale corre-
sponding to 6 milliampères. The galvanometer will now show a resistance of
1000 ohms, the scale being arbitrarily graduated in ohms.
If the resistance r is now cut out of circuit and another resistance of 1000 ohms
is inserted between the terminals, the galvanometer will make the samo
deflection as before, but, if a higher resistance X such as 2000 ohms or more is
inserted between the terminals, less current will pass through the galvano-
meter and the deflections of same will be smaller. These deflections will directly
correspond in ohms to the different resistances.
g
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:―
1.) An ohm meter for the direct reading of resistances, consisting of the com-
bination of a sensitive galvanometer and a galvanic battery with a controlling and
compensating resistance, whereby the deflection of the galvanometer due to an
inserted resistance of determined amount, may be maintained constant notwith-
standing variation in the electro-motive force of the battery, substantially as
herein before described.
2. An ohm meter for directly indicating resistances comprising in combination a
controlling and a compensating resistance, a sensitive galvanometer and a
galvanic battery arranged substantially as herein before described.
Date 541.
1900
MARKS & CLERK,
18, Southampton Buildings, London, W.C.,
13, Temple Street, Birmingham, and
25, Cross Street, Manchester, Agents.
MARKS & CLERK,
18, Southampton Buildings, London, W.C.,
13, Temple Street, Birmingham, and
25, Cross Street, Manchester, Agents.