Types of Buzzers: A Comprehensive User Guide

Ⅰ. The application of buzzer

1. Assist identification and navigation

Buzzers can be used to aid identification and navigation. For the visually impaired, the buzzer can be used as an aid. People identify direction, distance or obstacles through buzzer sound prompts. In some navigation systems, the buzzer can cooperate with the voice navigation function, which guides the user to the destination by issuing specific sound prompts.

2. Electronic games and toys

Buzzers play an important role in the field of entertainment and creativity. In electronic games and toys, buzzers produce sound effects that enhance the user experience. Whether it is the music in the game, the prompt sound of the end of the game, or the sound effect in the toy, the buzzer creates a richer entertainment world for users through the interaction of sound.

3. Medical and emergencies

Buzzers also play an important role in medical equipment and emergency situations. For example, in medical equipment, a buzzer can be used to send out an alarm signal to alert a doctor or nurse to a change in a patient's condition or an emergency. In addition, some emergency safety equipment, such as gas leakage alarms or emergency rescue devices, also use buzzers to attract the attention of people around and ask for help.

4. Security system

Buzzers play a vital role in safety equipment and systems. Among them, the fire alarm is a typical example. When fire or smoke is detected, the buzzer emits a high-volume sound to attract people's attention and remind them to take escape measures. Similar applications include security access control systems, anti-theft alarm systems, etc. The buzzer alarm can quickly alert people and protect people's lives and property.

5. Tips and alerts

As a powerful tool for alarms and reminders, buzzers are widely used in various devices. For example, a buzzer in a mobile phone can sound to alert the user when an incoming call or text message is received. This simple and effective reminder method prevents us from missing important notifications and messages. In addition, household appliances such as washing machines, microwave ovens, etc. will also use buzzers to indicate the completion of tasks or failures, so that we can take corresponding measures in time.

6. Embedded systems

Buzzers also play an important role in embedded systems. In industrial automation, buzzers are often used to indicate equipment status, errors, or warnings. Buzzers in embedded systems can convey information by emitting different tones or frequencies, allowing operators to quickly understand the health of the system.

Ⅱ. Classification of buzzers

1. According to the drive mode

(1) Active buzzer (self-excited buzzer)

The active buzzer only needs to be connected to a DC power supply to automatically emit sound (the frequency of the sound is relatively fixed). Its working and sounding principle is: the DC power input passes through the amplification and sampling circuit of the oscillation system to generate a sound signal under the action of the resonant device.

(2) Passive buzzer (other excitation buzzer)

There is no excitation source inside it. Only by giving it a square wave signal of a certain frequency can the vibration device of the buzzer vibrate, thereby achieving sound. At the same time, the input square wave frequency is different, and the sound emitted is also different. Therefore, the passive buzzer can simulate tunes to achieve musical effects.

Advantages:

① Cheap;

② The sound frequency is controllable;

③ Program control is convenient.

2. According to the difference of current

(1) DC buzzer

A DC buzzer is an electroacoustic device driven by DC current that converts a DC signal into an audible ripple-free form of sound.

(2) AC buzzer

An AC buzzer is an electroacoustic device driven by AC current, capable of converting AC signals into audible sounds. It is compact, lightweight and easy to carry. It is mainly composed of metal diaphragm, coil and magnetic core. When an alternating current signal passes through the coil, an alternating magnetic field is generated. When a magnetic field acts on a metal diaphragm, the diaphragm vibrates and produces sound.

3. According to the package

(1) SMD buzzer

The SMD buzzer is an electronic sounder with an integrated structure. It is characterized by the use of SMD packaging. The buzzer is mainly composed of piezoelectric ceramics and electrodes. When voltage is applied to piezoelectric ceramics, mechanical vibrations are produced, thereby producing sound.

(2) DIP buzzer

The DIP buzzer is an electroacoustic device. It is characterized by the use of pin-type connections. The buzzer can be driven by direct current or alternating current. When in use, electrical signals are transmitted to the DIP buzzer through pin connections, causing it to vibrate and emit sound. The DIP buzzer has the advantages of easy installation and easy replacement.

4. According to the structure

(1) Magnetic buzzer

In a magnetic buzzer, there is a ferrous disk fixed on a rod. There are magnets surrounding the rod that hold the disc in a resting position. A coil beneath the ferrodisk acts as an electromagnet. When current is supplied to the coil, the disc is attracted to the coil. When there is no current in the coil, the disc returns to its resting position. A weight above it controls the vibrations of the disc. When an oscillating signal is applied to the coil, the electromagnetic field generated by the coil also fluctuates, causing the ferromagnetic disk to vibrate. In this way, the magnetic buzzer produces a sound with the same frequency as the applied oscillating signal. Magnetic buzzers are available in both sensor and indicator configurations.

The magnetic buzzer operates from 1V to 16V. These buzzers produce lower rated frequencies and have lower sound pressure levels. Their current consumption is slightly larger compared to piezoelectric buzzers. Their current draw can be as high as 100mA. These buzzers have a small footprint and are typically used in high-end consumer applications.

(2) Piezoelectric buzzer

Piezoelectric buzzers use piezoelectric materials. When electricity is applied to the piezoelectric material, it deforms, causing vibrations and sound. Electromagnetic buzzers are widely used in electronic products such as computers, printers, copiers, alarms, electronic toys, automotive electronic equipment, telephones, and timers.

Advantages:

① It will not cause large vibrations due to looseness.

② Wide operating temperature range.

③ It will not produce arcing or radio frequency noise, and will not interfere with other lines.

④ Since there is no movable contact part, it has a long life and high reliability.

⑤ The piezoelectric buzzer is easy to install and has no electromagnetic coil or moving coil, so there is no need to worry about insulation deterioration and leakage.

⑥ Small and large volume. Its volume can reach 70 decibels/20cm, and the component thickness is only less than 1mm.

⑦ It is controlled by electronic circuits, so it can emit a variety of pleasant sounds and is not easily covered by noise.

Ⅲ. How to choose a buzzer?

1. Size

The size of the buzzer will affect the volume and frequency. Magnetic buzzers range in size from a minimum of 7mm to a maximum of 25mm, and piezoelectric buzzers range from 12mm to 50mm or larger.

2. Connection method

Commonly used methods include DIP, wire, SMD and locking screws.

3. Driving method

Both buzzers are self-excited and can sound as long as they are connected to direct current (DC). Because of the different operating principles, the magnetic buzzer needs to be driven by 1/2 square wave.

4. Current consumption

Magnetic buzzers vary in voltage from tens to hundreds of milliamperes. The piezoelectric buzzer saves much power. It only requires a few milliamps to operate normally. And when the buzzer is activated, it consumes about three times the current instantly.

5. Working voltage

Electromagnetic buzzers operate with voltages from 1.5 to 24V, while piezoelectric buzzers operate from 3V to 220V. However, it is generally recommended that the piezoelectric buzzer have a voltage of 9V or more to obtain a louder sound.

6. Sound pressure

Buzzers are generally tested based on 10 cm. When the distance doubles, its attenuation is about 6 dB. On the contrary, when the distance is doubled, its attenuation is about 6 dB. Electromagnetic buzzers can reach 85 dB/10 cm, while piezoelectric types can create louder alarm devices.

Ⅳ. How to connect the buzzer?

1. Parallel port connection method

The parallel port connection method refers to controlling the buzzer sound through the parallel port output data. General communication only requires 8 data lines and 1 control line. The advantage of this method is that it is fast, but it requires connecting multiple lines and is more complicated. It not only needs to connect the positive and negative poles of the buzzer to the data lines of the parallel port output, but also connects the control lines to the control pins.

2. Serial port connection method

The serial port connection method refers to controlling the buzzer sound through the serial port output high and low levels. We need to connect the positive pole of the buzzer to the output pin of the microcontroller and the negative pole to GND. By controlling the high and low levels of the output pin, we can control the buzzer to sound and stop. This connection is suitable for small buzzers controlled by single-chip microcomputers.

3. Different types of buzzer wiring methods

(1) Active buzzer

The active buzzer has an oscillator inside and only needs to be connected to the power supply to make a sound. It internally generates the signal at the desired frequency, so we can make it sound by connecting it directly to the power supply. The active buzzer has two terminals, positive and negative. When wiring, we need to connect the positive pole to the positive power supply and the negative pole to the negative power supply. The specific wiring steps are as follows:

① Determine the polarity of the power supply, and connect the positive and negative poles to the corresponding power ports.

② Connect the positive wire (usually red wire) of the buzzer to the positive pole of the power supply.

③ Connect the negative wire (usually black wire) of the buzzer to the negative pole of the power supply.

④ After the wiring is completed, turn on the power, and the buzzer will start working.

(2) Passive buzzer

Passive buzzers require external circuitry to operate. When using it, we need to access the oscillator to make sound. It should be noted that the passive buzzer cannot be directly connected to the IO port of the microcontroller. It needs to be controlled by an intermediate cascade transistor in order to achieve a stable and normal working state.

Ⅴ. How to test the quality of the buzzer?

1. Appearance inspection method

The buzzer is a device that is relatively easy to break. If the appearance is damaged, it will affect the normal use of the buzzer. Therefore, visual inspection is the first step to test the quality of the buzzer. During the appearance inspection, we need to pay attention to whether the pins of the buzzer are bent or broken, and whether the shell is deformed or damaged.

2. Use multimeter test method

Using a multimeter to test is an effective way to judge the quality of the buzzer. First, we set the multimeter to test the resistance, and then connect the test pens to both ends of the buzzer. If the multimeter shows the resistance value, the buzzer is working properly. Otherwise, there may be a problem with the buzzer.

3. Use DC power test method

We connect the electrode leads of the DC power supply to both ends of the buzzer. If the buzzer sounds, it means the buzzer is working normally. If there is no sound from the buzzer, there may be a problem with the wiring, power supply, or the buzzer itself.

Ⅵ. What should I do if the buzzer sound is too low?

1. Adjust the current

To get a louder sound, we need to provide enough current. Generally speaking, the current size of the buzzer will affect the size of the sound. If the current is too small, the buzzer will sound too quiet. We can adjust the size of the current by adjusting components such as resistors or current limiters in the circuit to obtain a louder sound. However, it should be noted that excessive current will not only make the buzzer make a loud sound, but also cause other components to burn out, so we need to adjust it carefully.

2. Add amplifier

The reason for the low sound of the buzzer may be insufficient power of the driving circuit. After adding an amplifier, the power of the drive circuit can be increased to make the buzzer sound louder. However, it should be noted that when adding an amplifier, we must pay attention to matching parameters such as the impedance and current of the amplifier, otherwise the amplifier will not work properly, or the amplifier may even be burned.

3. Replace the buzzer

If the sound of the buzzer is too low, it may be a problem with the buzzer device itself. At this time, we can try to replace a new buzzer device. Generally speaking, the sound of the buzzer device with better quality will be louder, which can effectively improve the problem of too small sound. But when replacing the buzzer, we need to pay attention to safety and ensure that the power is turned off to avoid electric shock or damage to other components.

Ⅶ. The difference between buzzer and speaker

1. Application Scenario

Due to the different sound characteristics and working principles of speakers and buzzers, their application scenarios are also different. Generally speaking, speakers are suitable for situations where complex sound effects such as music, advertising, and speeches need to be output, such as audio systems, car audio systems, and speech systems. The buzzer is suitable for situations where simple alarms, prompts, and other information need to be output, such as electronic timers, parking lot indicators, etc.

2. Working principle

There is a clear difference in the working principle between a horn and a buzzer. The speaker uses a diaphragm vibration method to produce sound, which amplifies the signal and vibrates the air through the diaphragm to produce sound. The buzzer, on the other hand, emits sound through electromagnetic oscillation, which causes the magnet to vibrate through voltage changes, thereby producing sound.

3. Sound effect features

The sound characteristics of horns and buzzers are also different. Due to the use of diaphragm vibration to generate sound, the speaker has a relatively rich sound quality and can output multiple tones. The sound of the buzzer is relatively single, and generally can only output high-frequency and monotonous sounds. Therefore, in situations where complex sound effects need to be output, we generally choose speakers.