General Information

Serial #

1666873

Part Number

4

Total Parts

12

AKA

N/A

Patents

N/A

General Description

metal casing and terminals/ synthetic top

Dimensions

Note: These reflect the general size for storage and are not necessarily representative of the object's true dimensions.

Length

9.5 cm

Width

5.0 cm

Height

17.4 cm

Thickness

N/A

Weight

N/A

Diameter

N/A

Volume

N/A

Lexicon

Group

Energy-electric

Category

Measurement

Sub-Category

N/A

Manufacturer

AKA

Leeds Northrup

Country

United States of America

State/Province

Pennsylvania

City

Philadelphia

Context

Country

Canada

State/Province

Ontario

Period

Unknown

Canada

An instrument used in the Calibration Unit of the Instrument Division of the Meteorological Branch of the Department of Transport of the Government of Canada. The Meteorological Branch became the Atmospheric Environment Service in 1971 and so this instrument was probably manufactured before that date. Part of a large collection of meteorological instruments acquired from the Meteorological Service of Canada (previously Atmospheric Environment Service) by the CSTM since 1967. MSC is the government agency responsible for collecting and disseminating meteorological data and forecasts in Canada. It was founded in 1871 in Toronto where it is still headquartered. The MSC was originally on the University of Toronto downtown campus but moved to Downsview in 1971 on land owned by UofT. The headquarters houses laboratories, research facilities and calibration and instrument maintenance facilities (now largely contracted out).

Function

A standard resistor is a resistor adjusted with high accuracy to a specified value, is little affected by variations in temperature and is substantially constant over long periods of time; this instrument was used in a meteorology instrument calibration unit to calibrate digital meteorological instruments such as barometers and thermometers.

Technical

An example of a standard resistance used for calibrating instruments. Leeds and Northrup's 1940 and 1946 catalogues list resistance model numbers 4020 to 4040 National Bureau of Standards type resistors, described as primary standards of resistance (Refs. 1-2). The 2030-B to 4045-B resistors would have been introduced at a later date. This type of resistance has four terminals with the heavy outer current terminals connected into the circuit and the lighter, inner terminals used to measure the potential drop. The resistance coils are mounted in oil in hermetically-sealed metal cases (Ref. 3).

Area Notes

Unknown

Details

Markings

incised white lettering on top reads '10000 OHMS/ CAT. 4040-B/ LEEDS & NORTHRUP CO./ PHILA, PA. MADE IN U.S.A./ 1666873'

Missing

appears complete

Finish

grey painted casing with plated parts/ black synthetic

Decoration

N/A