Use of Magnets & Electromagnets
Magnets & Electromagnets find widespread applications in various fields due to their ability to produce magnetic fields. Here are some key uses of magnets and electromagnets:
Examples of Magnets & Electromagnets
- The electric bell:
An Electric bell
When the bell button is pushed down, the circuit is complete and current flows. The electromagnet becomes magnetised and therefore attracts the soft iron armature. This enables the hammer to strike the gong.
As soon as the hammer moves out, the circuit is broken at the point of the contact screw. The current stops flowing and the Electromagnet now loses its magnetism. This allows the springy metal strip to pull back the armature, remaking contact at S and thus completing the circuit again. The cycle is then repeated and the bell rings continuously for as long as the bell button is pressed down.
- The simple magnetic relay:
A relay is a switching device which is used as an electromagnet. It has at least two circuits. One circuit can be used to control another circuit, without there being any direct electrical contact between them. The input circuit supplies current to the electromagnet. Only a very small current is needed.
When the current reaches a fixed level, the electromagnet attracts one end of the iron armature which is pivoted so that the other end acts as a lever. The lever opens and closes(depending on the design) the contacts in the second, or output, circuit. Thus the input circuit which works with a higher current/voltage(that is dangerous.