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What is self-drive buzzer?

Views: 176     Author: Site Editor     Publish Time: 2021-03-01      Origin: Site

Speaking of buzzers, we know two primary forms are piezoelectric buzzers, electromagnetic buzzers. both have active buzzers and passive buzzers. The piezoelectric buzzer has a piezoelectric buzzer plate, which contains two driving modes: self-drive buzzer and separately excited buzzer. So what are self-drive buzzers and separately excited buzzers?

What is the difference between self-drive buzzer and separately excited buzzer?

How does a self-drive buzzer work?

What should we pay attention to when we use a self-drive buzzer?

What is the difference between self-drive buzzer and separately excited buzzer?

Self-drive buzzer means that the piezoelectric buzzer has feedback poles, generally with three poles, that is, with 3 pins or 3 leads. Self-drive buzzer, or three-level buzzer, is made of a substrate plus a piezoelectric ceramic disc with a feedback electrode. It has three contact points and can weld three positive and negative wires, one of which is feedback electrode.

seld drive buzzerself drive buzzer dimension

Separately excited buzzer is generally aimed at piezoelectric buzzer, which is without driving circuit. It can also be called a passive piezoelectric buzzer, or a piezoelectric buzzer driven externally. Separately excited buzzer has no feedback pole, generally with only two lead poles, that is, with 2 pins or 2 lines. From the appearance point of view, the separately excited buzzer, that is, the two-terminal buzzer, is made of a substrate and a piezoelectric ceramic disc. It has only two contact points and can be welded with positive and negative wires.

Separately excited buzzerSeparately excited buzzer dimension

The most important difference between self-drive buzzer and separately excited buzzer lies in the working principle and application. Piezoelectric ceramic buzzer with feedback stage is generally used in buzzers for security and gas detection systems such as smoke detectors. The function of the feedback electrode is when the frequency is reaching the resonant frequency, the circuit satisfies oscillating condition, and the piezo element is driven with the oscillating frequency.
On the contrary, the separately excited buzzer has no feedback effect, and can only rely on the IC signal or the given frequency signal of the inductance circuit to match the frequency sound.

How does a self-drive buzzer work?

The working principle of a self-drive buzzer is that DC power input passes through the amplifying and sampling circuit of the oscillation system to generate a sound signal under the action of the resonance device. This principle is used to create a feedback signal which drives the oscillator. A self-drive buzzer works both ways: if you apply a voltage the piezo stretches, but also if it stretches it creates a voltage. The advantage of the self drive is that it will automagically work at its resonance frequency, where it produces the loudest sound.

What should we pay attention to when we use a self-drive buzzer?

1, The input voltage of the piezoelectric buzzer shall be lower than the specified maximum input voltage.

2, Avoid from being in direct current or Under AC voltage for long time to prevent the piezoelectric buzzer from breakdown, depolarization or conductive ion migration.

3, Set up the driving circuit as per recommended circuit for each different model. The recommended driving circuit for Kailitech Self-drive Piezo Transducers can be downloaded at https://www.kailitech.net/faqlist.html.

Values of resistors may need to be adjusted depending on specific models.

4, The self-drive piezoelectric buzzer must not be connected to the power supply in series with a resistor, which will cause irregular operation. If a resistor is necessary to control the volume, a 1µF capacitor must be used in parallel with the buzzer.

5, Do not cover the sound emitting hole on the front side of the buzzer.

6, When installing the piezoelectric buzzers, make sure no obstacles within 15mm from the sound emitting hole on the front of the buzzer.

Further attention to be paid for separately excited buzzer and self-drive buzzer including:

1. Do not touch the components with bare hands to avoid corrosion of the buzzer electrodes.

2. Pay attention to protect the working circuit from the surge voltage damage caused by stress, drop, vibration, and temperature change.

3. If a DC voltage is applied to the buzzer, charge migration may occur. Please be careful not to use the component under DC voltage for a long time.

4. Avoid pulling the wires excessively, otherwise the wires will break or the solder joints will fall off.

Learning something about self-drive buzzer and separately excited buzzer can help understanding the working principles of the self-drive buzzers. If you want to buy high-quality self-drive buzzers with fair price, Kailitech Company can provide you with the best value for money products. We also have other types of piezo buzzers and piezo transducers, having an independent factory and a complete production line. For further enquiries, please feel free to contact us at market@kailitech.com

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   Silvia Shen
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