A buzzer is a device that provides an audio signal in a circuit when a voltage is applied to it.
It comes in many different forms which include Mechanical, Electromechanical, and Piezoelectric.
A switch is an electronic component that has the function of allowing and preventing current flow when used in a circuit.
But, can a buzzer function as a switch in a circuit? A buzzer cannot function as a switch in a circuit. It’s primary function is to produce an audio signal in the form of ‘buzzing’ or ‘beeping’ when a voltage is applied to it. It does not have the ability to open and close a circuit the same way a switch does.
The main function of a buzzer and switch in a circuit
There are plenty of electronic components used daily in circuits. Individually, they have a certain function in the circuit that contributes to the overall functionality of the circuit.
A switch and buzzer are no different with each having a key function to play in a circuit.
Understanding what each does will help you understand why a buzzer cannot function as a switch in a circuit.
What is the main function of a switch in a circuit?
Let us first take a look at the switch.
Below, is a simple circuit with a load connected to a battery.
In this circuit the battery is continuously supplying the load with power.
However, at a certain point the battery is going to run out of energy and therefore will no longer be able to supply power to the load.
Having this sort of setup in the real world is not very applicable.
You are rarely going to need to have the battery constantly powering a load.
This is where the switch plays a crucial role.
An electrical/electronic switch is a component that connects or disconnects the conducting path in an electrical/electronic circuit, either allowing current to flow, or preventing it from flowing.
If we modify the diagram earlier and add a switch, we get the circuit below. The switch can be in two states ; Closed and Open.
In diagram A, the switch is Open, causing a break in the conducting path, thereby preventing current from flowing through the LED and powering it.
Diagram B has the switch closed which creates a conducting path and therefore allows current to flow from the battery to the LED.
So, you can see, the main function of the switch is to either allow or prevent current from flowing in a circuit.
What is the main function of a buzzer in a circuit?
Having the ability to produce sound in electronics has many different applications.
The buzzer is an electronic component that has the ability to produce sound when a voltage is applied to it.
This can be utilised in many applications.
One of the biggest applications where a buzzer plays a crucial role is a smoke alarm. When you are sleeping your sense of smell and sight are impaired.
If a fire starts in your home while you are sleeping, you will have no way of knowing. A buzzer provides a way of letting you know a fire has started through sound.
Other applications include alarm clocks, doorbells, electronic musical instruments, greeting cards, security systems and many more applications.
There are three different types of buzzers available ; Mechanical, Electromechanical, and Piezoelectric.
So, a buzzer’s main function in a circuit is to provide an audio signal.
Why a buzzer cannot be used as a switch in a circuit
Now that you know the function of a switch and buzzer in circuit, we can discuss why a buzzer cannot function as a switch in a circuit.
The main function of a switch is to close and open a circuit, thereby allowing and preventing current to flow respectively.
While the buzzer’s main function is to produce sound when a voltage is applied to it. It is primarily an output device that functions to provide an auditory signal which can be utilised in many different applications.
The buzzer does not have the ability to function as a switch, as it mechanically has no way of connecting and disconnecting the conducting path of a circuit the way a switch does.
What instance would a buzzer function a switch in a circuit?
There is an instance where a buzzer can disconnect the conducting path in a circuit.
This scenario could arise if the buzzer is damaged and causes an open circuit.
An open circuit occurs when two points in a circuit are physically disconnected thus representing a switch that is ‘open’.
If a buzzer is damaged, there is a possibility that there is a break in circuit within the buzzer thereby causing an open circuit.
However, this is far from a buzzer functioning as a switch in a circuit. You wouldn’t want to damage your buzzer just to open a circuit to make it ‘function’ like a switch.
Connecting a switch would be the more logical and sensible approach.
What other functions can a buzzer have in a circuit?
While a buzzer cannot function as a switch in a circuit, it does have another function other than just producing sound.
The piezoelectric type of buzzer has the ability to produce a voltage at its terminals when pressure is applied to the disc responsible for producing sound.
This opens a new set of possibilities for the piezoelectric buzzer.
It can be used in applications where a sudden force or constant pressure needs to be sensed and/or measured. The piezoelectric buzzer can be connected to a microcontroller analog input which can interpret the voltages from the buzzer.
Applications could include motion detection, door knock sensor, force measurement, pressure measurement, and many more.
What is the most basic circuit of a buzzer and how does it function
While there are many circuit configurations available for the buzzer, the most basic is one with a battery, switch, and buzzer (similar to our circuit at the beginning).
When the switch is closed, the battery energises the coil within the buzzer causing a rapid back and forth movement of a contact inside the buzzer causing a loud buzzing sound.
Opening the switch causes the coil to be de-energised which in turn will stop the buzzer from producing sound.
The piezoelectric buzzer requires a bit more than just voltage. It requires some sort of oscillator that is capable of producing a sinusoidal type wave. Just connecting it to a DC voltage will cause a click and no buzzing sound.
A microcontroller can be used to drive a piezoelectric type buzzer.
