How to Vary the Volume of a Buzzer
This is a pretty simple project we are going to do. We are going to create a simple buzzer circuit where we can increase or decrease the volume of the sound that the buzzer outputs.
To do this, all we do is take a 9-volt battery and connect it to a 1KΩ potentiometer which is hooked up to the buzzer.
The schematic of the circuit is below:
This is a more real life like representation of the circuit:
Okay, now we can do this in two ways. We can first turn the potentiometer all the way to the side where it gives out almost 0Ω of resistance. When we start at near 0Ω, the sound of the buzzer will be the loudest it will ever be, since the potentiometer's resistance is the lowest at this point; thus, at this point, the circuit outputs the greatest amount of current which is fed into the buzzer. Now as you turn the the potentiometer so that the resistance increases, you slowly begin to hear the sound of the buzzer get lower and lower. Eventually at around 450Ω, you cannot hear the sound of the buzzer anymore. It dies out. The resistance of the circuit now is higher and the buzzer doesn't receive enough current to play out sound.
Similarly, we can start with the buzzer turned all the way to the side where it gives out 10KΩ. When you start at 10KΩ resistance, the buzzer does not output any sound, so you hear nothing. This is because the resistance of the circuit is too high, so the current is very low and is not sufficient to drive sound out of the buzzer. Now as you turn the potentiometer so that the resistance decreases, you eventually hear the sound of the buzzer. This occurs at about 450Ω. As you keep turning it more, you hear the sound louder and louder. Turned all the way to the side so that the resistance of the potentiometer is near 0Ω, you hear the buzzer the loudest.
This is the way all volume sound manipulation occurs in hardware. This is the same way the volume of speakers are adjusted. So congratulations, you now know how to vary the volume of sound-outputting devices.