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D.C. Ammeter

Unidentified · Physics

The ammeter is mounted on a wooden base with a pair of vertical wooden supports to hold it upright.

The ammeter itself is a cylindrical unit affixed on its back to one of the vertical supports. The face of the ammeter is round, and there is an arc-shaped scale at the top of the face covered in glass. The scale is printed on cardboard calibrated for milliamps; however, the cardboard piece has fallen down into the front of the ammeter and is not entirely visible.

The back of the ammeter is a simple wooden board. A pair of wires emerge from the base of the board and run to one of two electrical terminals. One terminal is labeled with a plus sign (‘positive’) and the other a minus sign (‘negative’). A white arrow, pointing left , is printed on the flat wooden base next to the two terminals.

Also on the back of the board there is an handwritten ink inscription: “150-0-150 MILLIAMPERES, R=0.15”.

Accession Number:

Alternative Name:

Primary Materials: Wood, Metal, Glass, Cardboard


Old inventory number = phy1023. The face is engraved with “WESTON AMMETER”, “MADE BY WESTON ELECTRICAL INSTRUMENT COMPANY, NEWARK, N.J., U.S.A., NO. 55363.”

Dimensions (cm):

Height = 33 cm, Width = 27 cm, Length = 33 cm


Measuring amperage in an electrical circuit; possibly a demonstration device.


The scale at the top of the face has fallen down into the front of the ammeter and is not entirely visible.

Associated Instruments:


Weston Electrical Instrument Company, Newark, New Jersey, USA.

Date of Manufacture: 1880-1937


Department of Physics, University of Toronto

Additional Information and References:

Historical Notes: