Currently indexing
resistance standard (0.01 Ohm)
Date: circa 1903
Inventory Number: 2007-1-0109
Classification: Resistance Standard
Subject:
Maker: Otto Wolff (fl. 1870 - 1920)
Associate Name: (calibrated by) Physikalisch-Technische Reichsanstalt (founded 1887)
User: Harvard University Department of Physics (founded 1726)
Cultural Region:
Place of Origin:
City of Use:
Dimensions:
15.2 × 17 × 8.8 cm (6 × 6 11/16 × 3 7/16 in.)
Material:
Description:
Coil of manganin wound on a tube supported in a perforated nickel-plated case. Four terminals protrude from the hard rubber top: two straight vertical, and two in inverted "J" shape. There is a also a cylindrical knurled knob on the hard rubber top.
The resistance is 0.01 int. Ohm and is calibrated for 20°C.
The resistance is 0.01 int. Ohm and is calibrated for 20°C.
Signedon hard rubber top: O. Wolff Berlin / 2718 / Manganin;
Inscribedoval plate with an image of eagle inscribed: PTR. 93. / 1903;
on hard rubber top: 0.01 int. Ohm / bei. 20°C
on hard rubber top: 0.01 int. Ohm / bei. 20°C
FunctionFor suspension in mercury to a standard bridge set in an oil bath.
A resistance standard is not to measure the resistance of an electric conductor but rather to compare such a conductor to a temperature-fixed resistance. In other words, such a device is used to determine the value of an unknown current. To do so, a current in the conductor would pass through mercury (for the older type of standard resistance), into which the two leads from the resistor dip.
A resistance standard is not to measure the resistance of an electric conductor but rather to compare such a conductor to a temperature-fixed resistance. In other words, such a device is used to determine the value of an unknown current. To do so, a current in the conductor would pass through mercury (for the older type of standard resistance), into which the two leads from the resistor dip.
Curatorial Remarksobjects 2007-1-0108, 2007-1-0109, 2007-1-0110 were likely stored together and were used at the same location.
ProvenanceTriangle indicates it was used for the Physics 3, Jefferson Laboratory, Harvard University.
