What is a Buzzer : Working & Its Applications

There are many ways to communicate between the user and a product. One of the best ways is audio communication using a buzzer IC. So during the design process, understanding some technologies with configurations is very helpful. So, this article discusses an overview of an audio signaling device like a beeper or a buzzer and its working with applications.

What is a Buzzer?

An audio signaling device like a beeper or buzzer may be electromechanical or piezoelectric or mechanical type. The main function of this is to convert the signal from audio to sound. Generally, it is powered through DC voltage and used in timers, alarm devices, printers, alarms, computers, etc. Based on the various designs, it can generate different sounds like alarm, music, bell & siren.

The pin configuration of the buzzer is shown below. It includes two pins namely positive and negative. The positive terminal of this is represented with the ‘+’ symbol or a longer terminal. This terminal is powered through 6Volts whereas the negative terminal is represented with the ‘-‘symbol or short terminal and it is connected to the GND terminal.

History

The history of an electromechanical buzzer and piezoelectric is discussed below.

Electromechanical

This buzzer was launched in the year 1831 by an American Scientist namely Joseph Henry but, this was used in doorbells until they were eliminated in 1930 in support of musical bells, which had a smooth tone.

Piezoelectric

These buzzers were invented by manufacturers of Japanese & fixed into a broad range of devices during the period of 1970s – 1980s. So, this development primarily came due to cooperative efforts through the manufacturing companies of Japanese. In the year 1951, they recognized the Application Research Committee of Barium Titanate that allows the corporations to be cooperative competitively & bring about numerous piezoelectric creations.

Specifications

The specifications of the buzzer include the following.

• Color is black
• The frequency range is 3,300Hz
• Operating Temperature ranges from – 20° C to +60°C
• Operating voltage ranges from 3V to 24V DC
• The sound pressure level is 85dBA or 10cm
• The supply current is below 15mA

Types of Buzzer

A buzzer is available in different types which include the following.

• Piezoelectric
• Electromagnetic
• Mechanical
• Electromechanical
• Magnetic

Piezoelectric

As the name suggests, the piezoelectric type uses the piezoelectric ceramic’s piezoelectric effect & pulse current to make the metal plate vibrate & generate sound. This kind of buzzer is made with a resonance box, multi resonator, piezoelectric plate, housing, impedance matcher, etc. Some of the buzzers are also designed with LEDs.

The multi resonator of this mainly includes ICs and transistors. Once the supply is given to this resonator, it will oscillate and generates an audio signal with 1.5 to 2.kHz. The impedance matcher will force the piezoelectric plate to produce sound.

Electromagnetic

This type of buzzer is made with a magnet, solenoid coil, oscillator, housing, vibration diaphragm, and magnet. Once the power supply is given, the oscillator which produces the audio signal current will supply throughout the solenoid coil to generate a magnetic field.

Sometimes, the vibration diaphragm will vibrate & generates sound under the magnet & solenoid coil interaction. The frequency range of this ranges from 2 kHz to 4kHz.

Mechanical

These types of buzzers are subtypes of electromagnetic, so the components used in this type are also similar. But the main difference is that the vibrating buzzer is placed on the outside instead of the inside.

Electromechanical

The designing of these types of buzzers can be done with a bare metal disc & an electromagnet. The working principle of this is similar to magnetic and electromagnetic. It generates sound throughout the disc movement & magnetism.

Magnetic

Like a piezo type, magnetic is also used to generate a sound but they are different due to core functionality. The magnetic type is more fixed as compared to the piezo type because they work through a magnetic field.

Magnetic buzzers utilize an electric charge instead of depending on piezo materials to generate a magnetic field, after that it permits another element of the buzzer to vibrate & generate sound.
The applications of magnetic buzzers are similar to the piezo type in household devices, alarms such as watches, clocks & keyboards.

Working Principle

The working principle of a buzzer depends on the theory that, once the voltage is given across a piezoelectric material, then a pressure difference is produced. A piezo type includes piezo crystals among two conductors.

Once a potential disparity is given across these crystals, then they thrust one conductor & drag the additional conductor through their internal property. So this continuous action will produce a sharp sound signal.

Mounting Configurations

The mounting configurations of buzzers include the following.

• Panel Mount
• Wire Leads
• Screw Terminals
• Through Hole
• Spring Contact
• Surface Mount

How to use a Buzzer?

A buzzer is an efficient component to include the features of sound in our system or project. It is an extremely small & solid two-pin device thus it can be simply utilized on breadboard or PCB. So in most applications, this component is widely used.

There are two kinds of buzzers commonly available like simple and readymade. Once a simple type is power-driven then it will generate a beep sound continuously. A readymade type looks heavier & generates a Beep. Beep. Beep. This sound is because of the internal oscillating circuit within it.

This buzzer uses a DC power supply that ranges from 4V – 9V. To operate this, a 9V battery is used but it is suggested to utilize a regulated +5V/+6V DC supply. Generally, it is connected through a switching circuit to switch ON/OFF the buzzer at the necessary time interval.

Buzzer Circuit Diagram

The circuit diagram of the water level indicator using the buzzer is shown below. This circuit is used to sense or detect the water level within the tank or washing machine or pool, etc. This circuit is very simple to design using few components such as a transistor, buzzer, 300K variable resistor, and power supply or 9V battery.

Once the two probes of the circuit are placed in the tank, it detects the level of water. Once the water level exceeds the fixed level, then it generates a beep sound through a buzzer connected to the circuit. This circuit uses a BC547B NPN transistor however we can also use any general-purpose transistor instead of using 2N3904/2N2222.

This water level sensor circuit working is very simple and the transistor used within the circuit works as a switch. Once the two probes notice the water level within the tank, then the transistor turns ON & the voltage begins flowing throughout the transistor to trigger the buzzer.

How to Choose a Buzzer?

While choosing a buzzer or speaker, many principles need to consider like the following.

• Size of the product
• Consumption of Current
• Type of terminal
• Frequency Voltage
• Volume
• Type
• AC/DC Voltage
• The tone is Continuous/Pulsed
• Fixing – Pins, Leads/Surface Mount
• Output of Sound
• Feedback Option
• Piezo Elements

Advantages

The advantages of a buzzer include the following.

• Simply Compatible
• Frequency Response is Good
• Size is small
• Energy Consumption is less
• The Range of Voltage usage is Large
• Sound Pressure is high

Disadvantages

The disadvantages of the buzzer include the following.

• Controlling is a little hard
• Generates Annoying Sound
• Training is necessary to know how to repair the condition without just turning off.

Applications

The applications of the buzzer include the following.

• Communication Devices
• Electronics used in Automobiles
• Alarm Circuits
• Portable Devices
• Security Systems
• Timers
• Household Appliances
• Electronic Metronomes
• Sporting Events
• Annunciator Panels
• Game Shows

Thus, this is all about an overview of a buzzer data sheet that includes its working principle, pin configuration, specifications, circuit, advantages, disadvantages & its applications. It is an electromechanical, electromagnetic, mechanical, piezoelectric, electro-acoustic audio signaling device. This buzzer works through an audio signal source or oscillating circuit. A ring or beep or click indicates that a switch has been pushed. Here is a question for you, what are the features of a buzzer?