Transducer - Magnetic Buzzer

Transducer - Magnetic Buzzer - 1. Magnetic Transducer...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
1. Magnetic Transducer Magnetic transducers contain a magnetic circuit consisting of a iron core with a wound coil and a yoke plate, a permanent magnet and a vibrating diaphragm with a movable iron piece. The diaphragm is slightly pulled towards the top of the core by the magnet's magnetic field. When a positive AC signal is applied, the current flowing through the excitation coil produces a fluctuating magnetic field, which causes the diaphragm to vibrate up and down, thus vibrating air. Resonance amplifies vibration through resonator consisting of sound hole(s) and cavity and produces a loud sound. 2. Magnetic Buzzer (Sounder) Buzzers like the TMB-series are magnetic audible signal devices with built-in oscillating circuits. The construction combines an oscillation circuit unit with a detection coil, a drive coil and a magnetic transducer. Transistors, resistors, diodes and other small devices act as circuit devices for driving sound generators. With the application of voltage, current flows to the drive coil on primary side and to the detection coil on the secondary side. The amplification circuit, including the transistor and the feedback circuit, causes vibration. The oscillation current excites the coil and the unit generates an AC magnetic field corresponding to an oscillation frequency. This AC magnetic field magnetizes the yoke comprising the magnetic circuit. The oscillation from the intermittent magnetization prompts the vibration diaphragm to vibrate up and down, generating buzzer sounds through the resonator. Recommended Driving Circuit for Magnetic Transducer
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Introduction of Magnetic Buzzer (Transducer) Specifications: Rated Voltage : A magnetic buzzer is driven by 1/2 square waves (V o-p). Operating Voltage : For normal operating. But it is not guaranteed to make the minimum Sound Pressure Level (SPL) under the rated voltage. Consumption Current : The current is stably consumed under the regular operation. However, it normally takes three times of current at the moment of starting to work. Direct Current Resistance : The direct current resistance is measured by ammeter directly. Sound Output : The sound output is measured by decibel meter. Applying rated voltage and 1/2 square waves, and the distance of 10 cm. Rated Frequency
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This document was uploaded on 02/08/2012.

Page1 / 4

Transducer - Magnetic Buzzer - 1. Magnetic Transducer...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online