Testing & TroubleshootingQuestion 504 of 521
Two identical 60 W, 120 V lamps are accidentally wired in series across 120 V. Approximately what voltage will a DMM read across each lamp, and how will they glow?
a.120 V each; both at full brightness
b.About 60 V each; both glow dim
c.120 V on one, 0 V on the other
d.240 V each; both very bright
Explanation
Identical lamps in series split the 120 V roughly equally, so each sees about 60 V and both glow dimly at reduced power. They cannot each get the full 120 V in series (a, d), and equal lamps do not divide 120/0 (c). Unequal loads would divide the voltage unequally.
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