milliammeter
Inventory Number2012-1-0018
ClassificationAmmeter
Subject
Maker
Robert W. Paul Instrument Company
1891 - 1919
Cultural Region
Place of Origin
Place of Use
Dimensions9.5 × 22 × 19.6 cm (3 3/4 × 8 11/16 × 7 11/16 in.)
Material
DescriptionSquare wooden case, lid missing and flat leather handle in 2 pieces.
Square black metal textured front panel with fan-shaped window with arched scale and mirror strip. Knife edged a pointer with a hollow circle near its end hovering over a reflective band.
Double scale - top scale non-linear 0-15 milliamperes with bigger intervals as it goes up and lower scale linear from 0-15 milliamperes. From 1.5 to 1500 milliamperes depending on the setting of lozenge-shaped knob.
3 metal topped electrical connectors and 2 bakelite black topped connectors.
Raised disc with dial labeled "CLAMP FOR TRANSIT DEPRESS ↓AND TURN"
Square black metal textured front panel with fan-shaped window with arched scale and mirror strip. Knife edged a pointer with a hollow circle near its end hovering over a reflective band.
Double scale - top scale non-linear 0-15 milliamperes with bigger intervals as it goes up and lower scale linear from 0-15 milliamperes. From 1.5 to 1500 milliamperes depending on the setting of lozenge-shaped knob.
3 metal topped electrical connectors and 2 bakelite black topped connectors.
Raised disc with dial labeled "CLAMP FOR TRANSIT DEPRESS ↓AND TURN"
Signedprinted on face of meter: MILLIAMMPERES / NO. LY-712 / ROBT. W. PAUL, / LONDON & NEW YORK / PATENTED / TOTAL VOLTAGE 10 000 OHMS
FunctionAn ammeter for measuring small electrical currents. The "unipivot" design was developed by Paul, increasing sensitivity and decreasing friction relative to other ammeters with multiple moving parts.
Weston Electrical Instrument Corporation
Date: circa 1924
Accessories: standardization certificate from Jan 7, 1924 inside lid
Object number: 1997-1-1055
Weston Electrical Instrument Corporation
Date: 1901-1930
Accessories: standardization certificate on inner surface of lid
Object number: 2003-1-0038
Jewell Electrical Instrument Company
Date: circa 1931
Accessories: inside lid is a standardization certificate from Oct. 16, 1931.
Object number: 1997-1-0334
Weston Electrical Instrument Corporation
Date: 1920-1930
Accessories: shunt attached by hooks to electrical connectors on top
Object number: 1997-1-1039
General Electric Company
Date: 1945-1960
Accessories: plain cardboard box (with inscriptions)
Object number: WJ1262