General Information

Serial #

123389

Part Number

1

Total Parts

1

AKA

Microammeter

Patents

N/A

General Description

Molded bakelite case and adjustment screws. Glass window. Metal scale covered with enamel. Metal screws and binding posts.

Dimensions

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

Length

5.1 cm

Width

7.3 cm

Height

N/A

Thickness

N/A

Weight

N/A

Diameter

N/A

Volume

N/A

Lexicon

Group

Communications

Category

Radio

Sub-Category

N/A

Manufacturer

AKA

Ferranti

Country

England

State/Province

Unknown

City

Unknown

Context

Country

Canada

State/Province

Ontario

Period

1940-1960

Canada

Used for research at the NRC, Ottawa.

Function

Used to measure or monitor direct current in microamperes.

Technical

British-made permanent magnet moving coil type DC panel microammeter. This meter has a zeroing screw for adjusting the at rest position of the pointer. It also has an unusual feature controlled by a second screw. It is probably used to calibrate the torque produced when the current flows through the meter. This is an important development because it makes it much easier to keep the meter accurate and thus reduces the need to send the meter back to the manufacturer. This invention may be described in Great Britain patent 350,380, accepted June 1 1931. However, the patent mentions that it is used for moving iron instruments, not moving coil ones.

Area Notes

Unknown

Details

Markings

Printed on face: 'MICROAMPERES/ RES=78 MU/ F.S.D.=500../ FERRANTI/ MADE IN ENGLAND TYPE NO. 99F./ PATENT NO. 285633. NO.123389'

Missing

N/A

Finish

Black gloss bakelite. Cream/white meter face with black printing.

Decoration

N/A