Inductors and electromagnets are widely used components in electrical devices such as motors, generators, and transformers. While both components utilize a wire coil to establish a magnetic field, they each have functional differences that influence their suitability for a given application. Here, we highlight their similarities and differences while providing examples of how each is used in various electrical and electromechanical devices.
What are Inductors and Electromagnets?
An inductor is a two-terminal electrical component consisting of a wire wound into a coil. When electricity is applied to the coil, a magnetic field forms and gradually increases in strength. This magnetic field eventually collapses and is converted into electrical energy that is released back into the circuit.
The ability of inductors to temporarily store energy in an electromagnetic field makes them useful for:
- Slowing current surges and spikes in circuits
- Storing and delivering energy to a circuit
- Impedance matching
Inductors are categorized into the following types:
- Coupled inductors featuring two coils connected by electromagnetic induction
- Multi-layer inductors featuring a layered coil wrapped around a core
- Ceramic core inductors featuring a dielectric ceramic core
- Molded inductors created using plastic or ceramic housings
Like inductors, electromagnets consist of a coiled wire through which electricity flows to produce a magnetic field. The strength of the magnetic field is proportional to the number of turns in the coil. To further increase the magnetic field’s strength, the coil is often wound around a ferromagnetic or iron core.
In contrast to permanent magnets, the strength of an electromagnet’s magnetic field can be adjusted by modifying the amount of current flowing through the coil. The magnetic field can also be “turned off” by removing the electricity source from the magnet. This controllability makes electromagnets ideal for everything from powering electric doorbells to lifting and moving large pieces of metal.
Electromagnets include three main types:
- Resistive electromagnets featuring copper wires twisted around an iron core
- Superconducting electromagnets featuring cryogenically cooled coils of superconducting wire
- Hybrid electromagnets featuring a combination of resistive and superconducting electromagnets
Applications of Inductors and Electromagnets
One of the most well-known uses of inductors is in induction motors, where they generate the magnetic field required to rotate the motor’s shaft. The speed of the shaft’s rotation is directly proportional to the frequency of the power supply. Other inductor applications include:
- Filtering/blocking. In electrical circuits, inductors can filter, choke, or block higher-frequency alternating currents and smoothen output voltages.
- Transformers and converters. Inductors transfer and store energy in transformers and power converters.
- Tuning circuits. In tuning circuits, inductors allow a specific frequency to be selected.
- Sensors. Contactless electronic proximity sensors utilize inductors in the head of the sensor to enable inductive sensing.
- Ferrite beads. When used in ferrite beads, inductors help reduce electromagnetic interference in audio circuits.
- Electromagnetic relays. Electromagnetic relays are automatic switches that use electromagnetic induction to open or close the switch during operation.
The power and versatility of electromagnets make them an essential component of everything from small consumer electronics to mass-transit systems. In maglev trains, for example, electromagnets line the undercarriage of the train to levitate it above the guideway. Other applications of electromagnets include:
- Motors and generators
- Electric doorbells and buzzers
- Magnetic locks
- Headphones and speakers
- Induction heating systems used in cooking and manufacturing equipment
- Medical equipment such as MRIs and heart monitors
- Magnetic recording technology and data storage devices such as hard disks and tape recorders
- Laboratory research equipment such as mass spectrometers
- Particle accelerators
- Magnetic separation equipment
- Industrial lifting equipment
Custom Inductors and Electromagnets from Custom Coils
Inductors and electromagnets provide essential functions in a range of electrical systems and electronic devices. At Custom Coils, we design and manufacture custom inductors and electromagnets according to specific field requirements and performance expectations. From high-quality materials to expert design recommendations, our in-house resources and experience allow us to create long-lasting products for nearly any electrical application.