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Solenoid vs. Electromagnet: What's the Difference?

By Janet White || Published on January 6, 2024
A solenoid is a coil of wire generating a magnetic field when electric current passes through it, whereas an electromagnet is a magnet whose magnetic field is produced by an electric current, typically involving a solenoid wrapped around a magnetic core.

Key Differences

A solenoid is essentially a coil of wire that, when electric current flows through it, creates a magnetic field. An electromagnet, on the other hand, uses a solenoid but adds a ferromagnetic core like iron to amplify the magnetic field.
The magnetic field inside a solenoid is uniform and parallel to the length of the coil, making it useful in applications requiring a consistent magnetic field. Electromagnets, with their enhanced magnetic field, are used in applications needing stronger magnetic forces, like in electric motors.
Solenoids can be used to create electromagnetic fields for various applications, such as in valves or relays. Electromagnets find use in lifting heavy magnetic materials or in devices where the magnetic field needs to be switched on and off, like in MRI machines.
The strength of the magnetic field in a solenoid depends on the number of turns in the coil and the electric current passing through it. For electromagnets, the magnetic field strength also depends on the properties of the core material.
Solenoids are often used where space is limited due to their compact and elongated shape. Electromagnets, because of their stronger field and the need for a core, are typically larger and used where more magnetic strength is required.

Comparison Chart


Coil of wire
Coil of wire with a ferromagnetic core

Magnetic Field

Generated by electric current in the coil
Enhanced by the ferromagnetic core

Field Strength

Depends on coil turns and current
Depends on coil, current, and core material


Valves, relays, and small-scale devices
Electric motors, lifting heavy materials

Shape and Size

Generally compact and elongated
Often larger due to the core

Solenoid and Electromagnet Definitions


A solenoid may also refer to a cylindrical coil used in electromechanical devices.
He replaced the solenoid in the car's starter system.


Electromagnets are widely used in electric motors and generators.
The electromagnet in the motor converts electrical energy to mechanical energy.


Solenoids create a nearly uniform magnetic field within their coil.
The experiment used a solenoid to create a controlled magnetic field.


Electromagnets often involve a solenoid wrapped around a soft iron core.
He built an electromagnet by winding a coil around an iron nail.


Solenoids can be used to convert electrical energy into linear motion.
A solenoid in the printer moves the paper forward.


An electromagnet is a type of magnet where the magnetic field is produced by an electric current.
The scrapyard uses an electromagnet to move large metal pieces.


A solenoid is a coil of wire that produces a magnetic field when electrically energized.
The solenoid in the door lock activates when the correct keycard is swiped.


Electromagnets find applications in medical devices like MRI machines.
The MRI machine uses a powerful electromagnet to generate images of the body.


In physics, a solenoid is also a theoretical model for studying magnetic fields.
Her thesis modeled the behavior of particles in a solenoid's magnetic field.


An electromagnet can have its magnetic field turned on and off with electricity.
The crane's electromagnet is controlled to lift and release metal scraps.


A current-carrying coil of wire that acts like a magnet when a current passes through it.


A magnet consisting of a coil of insulated wire, usually wrapped around a steel or iron core, that is magnetized only when current flows through the wire.


An assembly used as a switch, consisting of a coil and a metal core free to slide along the coil axis under the influence of the magnetic field.


A magnet which attracts metals only when electrically activated


(physics) A coil of wire that acts as a magnet when an electric current flows through it.


A temporary magnet made by coiling wire around an iron core; when current flows in the coil the iron becomes a magnet


(engineering) An electromechanical device consisting of such a coil containing a metal core, the movement of which is controlled by the current.


(electronics) An electromechanical switch controlled by a solenoid; solenoid switch, relay.


(meteorology) The region of intersection between isobaric and isopycnal surfaces.


An electrodynamic spiral having the conjuctive wire turned back along its axis, so as to neutralize that component of the effect of the current which is due to the length of the spiral, and reduce the whole effect to that of a series of equal and parallel circular currents. When traversed by a current the solenoid exhibits polarity and attraction or repulsion, like a magnet.


A coil of wire around an iron core; becomes a magnet when current passes through the coil


What materials are used for an electromagnet's core?

Typically soft ferromagnetic materials like iron.

What is an electromagnet?

A magnet where the magnetic field is generated by an electric current, often using a solenoid with a ferromagnetic core.

Can a solenoid work without electricity?

No, it requires an electric current to generate a magnetic field.

Is the magnetic field of a solenoid always uniform?

It's nearly uniform within the coil but varies at the ends.

What are common uses for electromagnets?

In electric motors, lifting equipment, and medical imaging devices.

Can you control an electromagnet's field?

Yes, by adjusting the electric current.

What is a solenoid?

A coil of wire that produces a magnetic field when electricity passes through it.

Are solenoids used in everyday devices?

Yes, in devices like doorbells, valves, and relays.

How do you increase an electromagnet's strength?

By increasing the current or using a core with better magnetic properties.

Do solenoids have to be cylindrical?

They are typically cylindrical, but other shapes are possible.

Can solenoids operate at high frequencies?

Yes, they can operate at various frequencies.

Can solenoids create motion?

Yes, they can convert electrical energy into linear motion.

Can solenoids be miniaturized for small devices?

Yes, they are often used in small-scale electronic components.

Are electromagnets energy efficient?

They can be, especially when designed for specific applications.

What is the lifespan of a solenoid?

It varies based on usage and quality, but they can be quite durable.

Are there safety concerns with solenoids?

Generally safe, but precautions are necessary with high currents.

How are electromagnets different from permanent magnets?

Their magnetic field can be controlled and is not permanent.

What happens if you change the current in an electromagnet?

It changes the strength of the magnetic field.

Can electromagnets lose their magnetism?

Yes, if the electric current is turned off.

Are electromagnets used in transportation?

Yes, in applications like electric trains and magnetic levitation systems.
About Author
Written by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.

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