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D.C. Ammeter, Type R


The ammeter is set in a square, wooden, varnished stand, with a simple flat base and a vertical wood panel with the ammeter’s case set through it. A pair of triangular braces support the vertical piece on either side, sloping backwards.

The ammeter itself is cylindrical with a round face. A arc-shaped scale is in the top section of the face; the scale, set behind glass, runs from 0-20, calibrated in Amperes and has an indicator needle. Beneath the scale there is a maker’s mark and information about the ammeter.

On the back of the ammeter is a factory label detailing guarantee of quality. The back of the ammeter also has both positive and negative terminals, marked with large plus and minus signs, respectively.

Accession Number:

Alternative Name:

Primary Materials: Wood, Metal, Glass


Old inventory number on paper label: “PHY1021”.

The face of the ammeter is engraved and reads “Wagner Electric Mfg. Co.”, “Type R”, “St. Louis, U.S.A.”.

The scale reads “D.C. AMMETER”, “TYPE R”, “No. 24761”.

The back of the wooden stand has written on it, in black ink, “20 Amperes”, “R=0.04 ohms”.

On the back of the ammeter is a factory label detailing guarantee of quality.

Dimensions (cm): Height = 33, Width = 30, Length = 29


Measuring amperage; possibly a demonstration device.


Good: The back of the scale has been cracked and mended; the glue is discoloured. The meter shows signs of use and some corrosion around connections and screws.

Associated Instruments:


Wagner Electric Manufacturing Company, St. Louis, Missouri, USA

Date of Manufacture: Early 20th Cent.


Additional Information and References:

Historical Notes: