Uses of Electromagnet - Telephone Earpiece
- An electromagnet is used in the earpiece of a telephone. The figure shows the simple structure of a telephone earpiece.
- When you speak to a friend through the telephone, your sound will be converted into electric current by the mouthpiece of the telephone.
- The current produced is a varying current and the frequency of the current will be the same as the frequency of your sound.
- The current will be sent to the earpiece of the telephone of your friend.
- When the current passes through the solenoid, the iron core is magnetised. The strength of the magnetic field changes according to the varying current.
- When the current is high, the magnetic field will become stronger and when the current is low, the magnetic field become weaker.
- The soft-iron diaphragm is pulled by the electromagnet and vibrates at the frequency of the varying current. The air around the diaphragm is stretched and compressed and produces sound wave.
- The frequency of the sound produced in the telephone earpiece will be the same as your sound.