Principles and practice of electrical engineering (1914)
Gray, Alexander, 1882-1921 · New York [etc.] McGraw-Hill Book Company, inc. · leaf 221
nil 11111111111111111 85 90 95 100 105 … B—Scale when the frequency is 100 cycles. C—External appearance.Fig. 215.—Vibrating reed type of frequency meter.
Electrical engineering
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