The term ‘solenoid’ was given by Andre’-Marie Ampere, French physicist, to designate a helical coil. A solenoid is more commonly described as a coil which winded into a tightly packed helix. The coil’s length is greater than that of its diameter, wrapped around a metallic core, producing a uniform magnetic field in the volume of space whenever an electric current is passed through it.
Solenoid is a type of electromagnet which serves the purpose of generating a controlled magnetic field. A solenoid is simply a coil of wire but when electric current is passed through it, it acts as an electromagnet. Electromagnets can be switched on and off and also strengthened and weakened by increasing or decreasing the flow of electric current through them.
WORKING OF A SOLENOID
The core material of a solenoid is ferromagnetic in nature which means that there is concentration of magnetic lines of flux. This is turn increases the inductance of the coil beyond the obtainable inductance capacity within an air-core coil of the same number of turns and of the same dimension.
When electric current is passed through the coil, the resulting magnetic flux tends to exist in the core material. Some of the flux appears outside the coil but near the ends of the core and some small amount of flux is also present outside the coil, off to the side.
A solenoid chime is winded on a hollow, cylindrical, plastic or phenol form which has a movable iron or steel core. The core travels in and out of the coil on its axis. The coil is vertically oriented and rests below the coil center. With application of a current pulse, the magnetic field tends to forcefully pull the core in the upward direction. The coil is carried above the center of the coil by inertia. At the center of the coil, the core strikes a piece of metal, creating a loud ‘ding’ sound.
USES OF A SOLENOID
- They are used in hotel room door locks.
- Also used in MRI machines, hard disk drives, microphones, speakers.
- Also used in air conditioning systems.
- Also used in cards and power plants.
- Solenoids can be used as electromagnets.
- Can be used as inductors in electronic circuits.
- It can also be used as miniature wireless receiving antennas.
- They are used to generate a controlled magnetic field.
- Also used as wireless receiving antennas.
- Solenoid comes in handy with easy control of leakage, fast operation, and long service.
- They have a fast operation.