Signedon dial: HARTMANN & BRAUN A.G. / FRANKFURT A.M. / No. 428
Inscribedbase marked: James G. Biddle / Philadelphia; twice marked: PROPERTY OF / HARVARD ENGINEERING SCHOOL; HARVARD UNIVERSITY 1179
FunctionFor experimentation and demonstration of the high voltages induced in a secondary winding when the current in the primary windings is abruptly disrupted.
ProvenanceHarvard University Engineering School, removed to the collection November 1956.