In which device inductor cannot be used?

Question

Examoogle · Accepted Answer

Dielectric

Explanation: An inductor is a passive electrical component that stores energy in a magnetic field when electric current flows through it. A dielectric, by definition, is an insulating material that can be polarized by an applied electric field to store energy electrostatically, which is the functional basis of a capacitor, not an inductor.

Working Principle: The principle of an inductor is based on Faraday's Law of Induction, where $V_L = L \frac{di}{dt}$. Conversely, a dielectric serves as the medium between two conductive plates in a capacitor, where it opposes the flow of current and supports an electric field, governed by $Q = CV$. Therefore, an inductor requires a conducting coil (often with a magnetic core) to function, making it incompatible with dielectric material properties.

Key Formulas: $V_L = L \frac{di}{dt}$ — Voltage across an ideal inductor; $W = \frac{1}{2} LI^2$ — Energy stored in a magnetic field

Key Points: Inductors utilize magnetic fields, while dielectrics facilitate electric fields.; A choke is specifically an inductor designed to block high-frequency AC.; Filters use a combination of inductors and capacitors to shape frequency response.; Dielectrics are insulators that decrease the electric field between capacitor plates.

Advantages: Inductors provide filtering capabilities in power supplies.; Inductors prevent rapid changes in current, protecting sensitive circuits.

Disadvantages: Inductors cannot be used as insulators or purely electric storage devices.; Physical size and saturation limits restrict inductor usage at high power.

Applications: Inductor: Transformers, Chokes, Tuning circuits.; Dielectric: Capacitors, Insulation, Printed Circuit Board substrates.

Additional Info: Transformers rely on mutual inductance between two coils, which requires inductive elements.. Option A, B, and C rely on magnetic induction principles, whereas Option D is a material property distinct from electromagnetic induction.

Answer: D is correct — Dielectric materials are insulators used for electrostatic energy storage, whereas inductors are electromagnetic components defined by wire-wound magnetic induction.

Exam Tip: Always remember: Inductors block $AC$ (due to $X_L = 2\pi fL$) and pass $DC$, whereas Capacitors ($X_C = \frac{1}{2\pi fC}$) pass $AC$ and block $DC$.

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