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October 13, 1956


JAMA. 1956;162(7):644. doi:10.1001/jama.1956.72970240008008c

Some manufacturers and distributors of diagnostic instruments would lead physicians to believe that each new electrical device requires its own specially designed voltage adapter or transformer. However, since most hand instruments operate on 1.5 to 12 volts and draw a current of from 0.2 to 2.5 amp., it seemed quite feasible to construct a single low-voltage supply that could serve all of the instruments the average practitioner might use in his office. The valuable features of a small portable transformer developed recently1 have been combined with a number of new improvements, in order to provide a maximum of convenience and safety.

The final unit is shown in the figure. Four sets of outlets are provided on the front panel, two pairs with an output of 3 volts or less, one pair for 6-volt instruments, and one pair for 12 volts. The outlet jacks are color-coded green, yellow, and red,