Hallberg, Josef Henrik, 1874- · New York city, The Moving picture world · leaf 175
cured from the positive crater of a direct-current 25-ampere arc and for better results the current may be in-creased to 30 amperes and in special instances, where abrilliant picture is necessary, the current at the arc maybe increased from 30 to 50 amperes. In chapter 2 are described the methods… … Fig. 99 MOTION PICTURE ELECTRICITY 169 rupted or, in other words, the arc is dead as many timesper second as the current reverses. The number of re-versals of the current depends upon the cycles or fre-quency of the system. In Fig. ii you will find a graphical demonstration ofan alternating-current…
Motion picture theaters · Electric lighting
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