🔊 Buzzer Circuit
Make your first noisy circuit with a battery, a buzzer and a switch.
🧰 What you need
- 1 active piezo buzzer (3–5 V type, "active" means it beeps by itself)
- 2 AA batteries in a battery holder with wires (3 V)
- 1 small push button or slide switch
- 3 alligator-clip wires or jumper wires
- Optional: a small breadboard
🔧 Let's build it!
- Look at the buzzer. One leg (or wire) is marked + or is longer. That's the positive side.
- Connect the battery holder's red (+) wire to one side of your switch.
- Connect the other side of the switch to the buzzer's + leg.
- Connect the buzzer's − leg back to the battery holder's black (−) wire. You've made a loop!
- Press the button. BZZZZ! Let go and it stops.
- Challenge: tap out a secret code to a friend. (Try our Morse code tool in The Lab!)
🔬 What's happening?
Electricity only flows when there is a complete loop from the battery's + side, through the parts, and back to the − side. The switch is like a drawbridge: when it's up (open), the path is broken and nothing flows. When it's down (closed), electricity rushes around the loop. Inside the buzzer is a thin disc that wiggles back and forth thousands of times a second, pushing the air to make sound waves.