However, noteworthy is the first use of the buzzer invented by Johann Wagner in 1839 and later modified by John Mirand, who added a bell to the vibrating hammer. The main disadvantage of the electromechanical buzzer is obvious: the presence of a moving element wears out the mechanism, and the spring weakens over time, and therefore the buzzer's operating time between failures is no more than 5000 hours. Of course, a buzzer based on a relay in the course of its operation not only generates strong impulse noise in the power supply circuit, but also emits strong interference into the radio air, therefore, buzzers are used, among other things, for testing various equipment for noise immunity. ![]() The oscillation of the relay armature produces a buzzing sound. So the process is repeated over and over. When the contacts are opened, the relay winding stops receiving power, the magnetic flux in the core disappears, which means that the moving contact that just closed the relay power circuit is released, and the spring transfers the circuit to the initially closed state.Īnd now, the contacts are closed again, the coil receives power again and the core again attracts the movable contact of the relay, again opening its own supply circuit. ![]() When a current flows in the operating circuit of the buzzer, the relay winding is excited, which means that the magnetic flux in its core increases, under the influence of which the contacts immediately open through which the winding itself was just powered. The principle of operation of the buzzer is very simple. Historically, the first appeared electromechanical buzzer, which is an electromechanical relay with normally closed contacts, through which the coil of this relay is connected to a current source. ![]() Today, buzzers are electromechanical and piezoelectric. In fact, it is a sound-emitting device traditionally used as a signaling device. The word "buzzer" comes from the German "summen" - to buzz.
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