How does a microphone pick up sounds?
Just like we use our diaphragms to sing, microphones use their diaphragms to pick up sounds and convert them into electrical currents.
Asked by: Luigi Filletti, Malta
A microphone converts sound into a small electrical current. Sound waves hit a diaphragm that vibrates, moving a magnet near a coil. In some designs, the coil moves within a magnet.
Other microphones, such as condenser microphones, work on the principle of capacitance. Capacitors consist of parallel conducting plates that store charge and are used to smooth out signals like voltage variations in a power supply. In a condenser microphone, the incoming sound vibrates one plate of a capacitor. The varying capacitance is converted into a corresponding electrical signal.
Subscription offers you will love!
- Spread the cost and pay just £3.50 per issue when you subscribe to BBC Science Focus Magazine.
- Alternatively, lock in for longer and pay just £37.99 per year, saving 51%!
- Risk - free offer! Cancel at any time when you subscribe via Direct Debit.
- FREE UK delivery.