器材原始說明資料: Counter, Electric.
Stoelting, C. H. (1928-1945) No.22407
http://physics.kenyon.edu/EarlyApparatus/Mechanics/Timer/Timer.html
Counter, Electric. This electric counter has withstood the test of time and is the only type of electric counter likely to give satisfaction in the Psychological Laboratory or Clinic for tapping and similar operations of a high degree of rapidity. It has been used in laboratories and clinics for the last twenty-five or thirty years and to date nothing in the shape of a counter has been devised that approaches it in reliability and convenience. The dial is graduated in 100 divisions, and the counter will register 9999 and may be set to zero from any point on the dial. A 6V. battery furnishes the necessary current.  |
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