The electric bell was one of the early practical applications of electromagnetism. This device has developed into most complicated systems for the transmission of signals. Trembler bells have survived with very little change and may operate from ELV, direct or alternating current. For an appreciation of the action, an actual bell should be carefully examined. The movement is worth studying and memorising as it forms the basis of relays and the more complex communication arrangements.
KeywordsAlarm System Call Point Continuous Ringing Alarm Sounder Electrical Installation
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