Signedon metal plate on top panel: LEEDS & NORTHRUP CO./ Philadelphia, Pennsylvania/ Made in U.S.A.
FunctionFor use with L&N 7551 or 7552 (types K1, K2) potentiometer for measuring current. Ranges from 0.075 amps to 7.5 amps with an error of + or - 0.04%. Current = Volt reading on potentiometer divided by Resistance of shunt. Ventilated to avoid overheating.
Historical AttributesMay have been used for teaching in the Physics 3 course, Physics Department, Harvard. (See Curatorial Remarks).
Primary SourcesReferences: "Type K Potentiometer", L&N Bulletin No. 755, 1930. "Type K Potentiometer and Accessories," L&N Cat. EH22(1), 1948. "Electrical Measuring Instruments," L&N Cat. E, 1948.
ProvenanceDepartment of Physics, Harvard University