Sound sources, everything you need to know about buzzers

Publish date 2021-07-06
Buzzers are small devices that convert electricity into a sound signal. They are able to generate a sound in the range of human audibility, which is a specific sound information. The sound of the buzzer is so piercing that it can be heard even in a very noisy place. Buzzers are usually used as sound signaling devices. They transmit, depending on the type, a buzzer can be used to produce different types of sounds.

Types of buzzers

When buying an appropriate buzzer, it is inevitable to choose its type. There are 2 equally important divisions into buzzers. The first one because of the way it works. This division includes buzzers with a generator and buzzers without a generator. The difference between them is that it is enough to bring a constant voltage to the buzzer with the generator and the internal generator system will properly control the sound-producing element. On the other hand, for Buzzers without a generator, we have to provide a signal of the appropriate frequency ourselves so that the buzzer starts to trigger the sound. The second division divides them according to the executive element. Piezo and electromagnetic buzzers are available. We offer these types. Which buzzer to choose? The next sections of this article will help you make that decision.

Piezo buzzer

As the name suggests, it works thanks to the piezoelectric effect. The acoustic signal is produced by a diaphragm which is attached to a piezoelectric plate. The plate, under the influence of the flowing alternating current, expands and contracts, causing vibrations transferred to the diaphragm.

Magnetic buzzer

A magnetic or electromagnetic emitter is similar in structure to a small loudspeaker. The part that produces the acoustic signal is the diaphragm. The diaphragm generates sound due to the fact that it is connected to a magnet that moves in the magnetic field of the coil.

How to choose the right buzzer

The multitude of types of sound signals makes it sometimes difficult to choose the right buzzer. It is important to precisely define the parameters and requirements for the sound source that will be installed in your product. Below are some parameters you need to know before buying a buzzer.

Working voltage

You should pay attention to the operating voltage in the circuit. Some buzzers have a wide voltage tolerance range - 3 ~ 250V, others a much narrower one - 1 ~ 16V. You need to know what values will be maintained in your installations. If you are unsure, choose a piezo buzzer. It is this type that has a wide range of tolerances. In the event that the circuit has low voltage, choose a magnetic buzzer - this one has a narrow operating voltage range.

Sound pressure level (SPL)

Do you already know how loud the sound should be produced by your device? The sound pressure level is a quantity that indicates how loud a sound can be produced by a device. SPL is the variation from atmospheric pressure caused by a sound wave. It is a unit of measure that is expressed in Pascals. It makes it easy to compare two audio output devices. Generally, the SPL is proportional to the input voltage (buzzer operating voltage). The most common buzzers with SPL are at the following levels: 80 dB, 85 dB, 90 dB, 95 dB, although there are also some with a sound pressure level of up to 105 dB.

Resonant frequency

The resonant frequency is a parameter that is particularly important if you will install the buzzer in a sensitive, delicate device. It determines the frequency at which the buzzer tends to vibrate. Typically this is the frequency at which the sound emitter has the highest sound pressure level. Buzzers produce the loudest sounds, consuming the least input power when they vibrate at their resonant frequency. Signal buzzers are typically designed to operate in a range close to its resonant frequency.