Industries typically use chokes and inductors for altering, filtering, and delivering electrical current. However, for using these devices effectively for machinery and devices that rely on electrical power, it is essential to understand the difference between chokes and inductors, as the design of these electrical components must meet specific applications’ requirements.
Despite a choke being a type of inductor, it has a design, functionality, and application that sets it apart from other inductor designs. Physically, this electrical component looks like a donut-shaped core and has an insulated wire wrapped around it.
As its name implies, primarily, a choke restricts or cuts off high-frequency components from alternating currents flowing through it. It allows only low-frequency currents, including direct currents to pass through. Therefore, a choke eliminates most of the high-frequency currents and allows only low-frequency and DC currents to pass through to the load.
Another function of the choke is its ability to restrict a steep rise and fall of current and voltage in circuits. A fast rise in voltage can damage insulation. Conversely, a choke can also generate high voltages such as those necessary to strike an arc for starting fluorescent tubes.
On the other hand, inductors primarily store electrical energy as a magnetic field when current passes through them. For this purpose, inductors typically have a magnetic core wrapped with an insulated coil. Therefore, all chokes are inductors, but the reverse is not true—not all inductors are chokes. Many technologies use inductors for various functions.
For instance, inductors are necessary to filter a band of frequencies by increasing the impedance for these frequencies. Inductors also act as proximity sensors without making physical contact, as the magnetic fields of the inductor and the object can interact. Multiple inductors, using the same magnetic field, constitute a transformer that can effectively transform, or step-up or step-down voltages. Inductors typically arranged circularly around a motor shaft, can interact with other stationary inductors to provide the torque necessary to rotate the motor shaft. Switching power supplies use inductors to temporarily store and supply electrical energy in and from their magnetic fields.
An inductor has a much wider functionality as compared to a choke. For instance, an inductor acts as a choke when filtering high-frequency signals. While the choke’s primary function is to remove high-frequency signals and allow low-frequencies and DC signals to pass through, the primary function of an inductor is to store energy in its magnetic field.
In RF circuits, a choke typically protects against the ingress of high-frequency signals, assuring operational stability. On the other hand, an inductor, in parallel or in series with a capacitor can act as a tuned circuit. Such tuned circuits allow the RF circuit to oscillate at a specific band of frequencies as determined by the inductor and capacitor combination.
Both chokes and inductors are critical in circuits that must conform to EMI/EMC or electromagnetic interference and compatibility standards. They block the generation and reception of unwanted signal frequencies in equipment. They prevent the electromagnetic spectrum of the device from increasing beyond a specified level as directed by the standards.