Description
Abstract
This project focuses on Automatic college bell with an announcement system. A bell is a hollow vessel usually of metal, but sometimes of horn, wood, glass, or clay, struck near the rim by an interior clapper or exterior hammer or mallet to produce a ringing sound. Bells may be categorized as idiophones, instruments sounding by the vibration of resonant solid material, and more broadly as percussion instruments, College bells have an armature containing a permanent magnet, so that this is alternately attracted and repelled by each half-phase and different polarity of the supply. In practice, the armature is arranged symmetrically with two poles of opposite polarity facing each end of the coil, so that each may be attracted in turn. No contact breaker is required, so the bells are reliable for long service. For this reason, they were widely used for telephone bells. 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. The seminar is to illustrate the use of automatic college bell to announce college hourly activities. Thus reducing the stress of visit the analog bell stand every hour of the day and night. The device comprises the power supply unit, the control unit, and the output unit. And, the introductory part, the basic operational principle, and the description of the components etc are contained in the various chapters of this write-up.
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