General Information

Serial #

18492

Part Number

4

Total Parts

4

AKA

Standard capacitor

Patents

N/A

General Description

metal casing and parts/ synthetic parts

Dimensions

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

Length

10.2 cm

Width

8.3 cm

Height

5.0 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

GENERAL RADIO

Country

United States of America

State/Province

Massachusetts

City

Concord

Context

Country

Canada

State/Province

Ontario

Period

1970's-1980's

Canada

An instrument of a type used by the Meteorological Service of Canada, probably in its calibration laboratories. 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 device composed of two conducting surfaces separated by a dielectric (in this case mica), which has the ability to store electrical energy and block the flow of direct current; this type served as a fixed standard for laboratory use.

Technical

An example of a standard capacitor used for calibrating instruments. The 1409 standard capacitor first appears in General Radio's 1959 catalogue (Ref. 1). It is a fixed mica capacitor of very high stability for use as two or three terminal reference or working standards in the laboratory. The capacitor consists of a silvered mica and foil pile, spring-held in a heavy metal clamping structure for mechanical stability. The units are housed in , with silica gel to provide continuous dessication, in aluminum cases, sealed with high-temperature potting wax. There is a well in the casing wall for the insertion of a dial thermometer, three jack-top binding posts on the casing top, and removable plugs on the bottom for parallel connection without error. The 1409-F had a nominal capacitance of 0.001 microfarads. The last GR catalogue in the CMST trade literature collection to list the 1409 capacitor was issued in 1972 (Ref. 2). In 2000 IET Labs acquired the GenRad standards, decade box, audio and strobe product lines and in 2007 continued to market, service and support these products, including the 1409 series of standard capacitors (Ref. 3).

Area Notes

Unknown

Details

Markings

white and black lettering on black and grey plate attached to top reads 'STANDARD CAPACITOR/ TYPE 1409-F SERIAL 18492/ 1.0 uF +/-0.05%/ 500V MAX PEAK/ BELOW 750 KC/ SEALED UNIT DO NOT DRILL CASE/ GENERAL RADIO COMPANY/ CONCORD MASSACHUSETTS USA'/ inventory label on underside reads 'ACSL FEB 84/ DS-0136'/ black stamped '194513' on underside/ white label on side with handwritten '305'/ white label on side with handwritten '# 304'

Missing

appears complete

Finish

black painted? casing/ plated parts/ grey and black synthetic/ black feet

Decoration

N/A