Power Sources
Electric bells are typically designed to operate on low voltages of from 10 to 24 V AC or DC. Before widespread distribution of electric power, bells were necessarily powered by batteries, either wet-cell or dry-cell type. Bells used in early telephone systems derived current by a magneto generator cranked by the subscriber. In residential applications, a small bell-ringing transformer is usually used to power the doorbell circuit. So that bell circuits can be made with low-cost wiring methods, bell signal circuits are limited in voltage and power rating. Bells for industrial purposes may operate on other, higher, AC or DC voltages to match plant voltages or available standby battery systems.
Read more about this topic: Electric Bell
Famous quotes containing the words power and/or sources:
“The terror of the atom age is not the violence of the new power but the speed of man’s adjustment to it—the speed of his acceptance.”
—E.B. (Elwyn Brooks)
“I count him a great man who inhabits a higher sphere of thought, into which other men rise with labor and difficulty; he has but to open his eyes to see things in a true light, and in large relations; whilst they must make painful corrections, and keep a vigilant eye on many sources of error.”
—Ralph Waldo Emerson (1803–1882)