Inductor Definition and 456 Threads

An inductor, also called a coil, choke, or reactor, is a passive two-terminal electrical component that stores energy in a magnetic field when electric current flows through it. An inductor typically consists of an insulated wire wound into a coil.
When the current flowing through the coil changes, the time-varying magnetic field induces an electromotive force (e.m.f.) (voltage) in the conductor, described by Faraday's law of induction. According to Lenz's law, the induced voltage has a polarity (direction) which opposes the change in current that created it. As a result, inductors oppose any changes in current through them.
An inductor is characterized by its inductance, which is the ratio of the voltage to the rate of change of current. In the International System of Units (SI), the unit of inductance is the henry (H) named for 19th century American scientist Joseph Henry. In the measurement of magnetic circuits, it is equivalent to weber/ampere. Inductors have values that typically range from 1 µH (10−6 H) to 20 H. Many inductors have a magnetic core made of iron or ferrite inside the coil, which serves to increase the magnetic field and thus the inductance. Along with capacitors and resistors, inductors are one of the three passive linear circuit elements that make up electronic circuits. Inductors are widely used in alternating current (AC) electronic equipment, particularly in radio equipment. They are used to block AC while allowing DC to pass; inductors designed for this purpose are called chokes. They are also used in electronic filters to separate signals of different frequencies, and in combination with capacitors to make tuned circuits, used to tune radio and TV receivers.

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  1. J

    B Why does my LC circuit not oscillate its energy between Electric & Magnetic fields?

    My inductor has 8 turns, 4 cm diameter and 4 cm length. The capacitor I use is a 1 microfarad polyester capacitor. When the copper wire inductor is connected to DC voltage the compass needle is deflected by 90 degrees and the multimeter detects 1 A or 1000 mA of current. When DC is switched...
  2. E

    What explains the current flow in a LC circuit?

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  3. L

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  4. S

    B LC resonance with high Q factor, Inductor with non magnetic core

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  5. A

    Engineering Short vs Open Circuit: Is That Correct?

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  6. J

    Trying to analyze a half wave rectifier with inductor and DC source

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  7. W

    Electronics Would This Setup for a Ball Bearing Accelerator Work?

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  8. W

    Advantages of Circular vs Cylindrical Inductor Core?

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  9. abdulbadii

    I Outright understanding L/R inductor time constant

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  10. S

    Exploring Inductor Design for Audio Applications

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  11. J

    I How does a ferromagnet increase the inductance of an inductor?

    Inductance according to Faraday's law depends on a changing magnetic field. The magnitude of the induced emf depends on the magnitude of change in the magnetic field per change in time. Based on that, how does adding a constant magnetic field (a ferromagnet), increase the inductance of an inductor?
  12. J

    I Does an inductor always create a back EMF?

    Let’s use a solenoid for example. Let’s say you have a current that passes through a solenoid clockwise. Due to Faraday’s law of induction, the induced current from the magnetic field from an increasing current opposes the initial direction of current causing resistance. If the initial current...
  13. J

    Find the inductance of an inductor in a circuit

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  14. A

    I Inductor questions (generate a voltage opposing the source voltage?)

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  15. MadelineChoate

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  16. E

    Total current needs to go through the inductor L1, How ?

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  17. V

    B Why does an inductor discharge?

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  18. PhysicsTest

    Are My Inductor Equations Correct?

    I have redrawn the circuit as below 40 - (I2+0.5)200 - (I2 + IL)*300 = 0 -> eq1 -(I2 + IL)*300 - IL*280 - 4*dIL/dt = 0 -> eq2 Are my equations correct?
  19. PhysicsTest

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  20. A

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  21. T

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  22. awen

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  23. H

    The Direction and magnitude of current in the inductor

    I understand that the current is going rightward because of the negative sign in the equation above, but why is the current increasing not decreasing? The current doesn't stay constant because it changes with the time based upon the equation above again.
  24. PhysicsTest

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    a. When the transistors are ON. ##V_{CC} = V_L## ##V_{CC} = L \frac{di_L} {dt} ## ##i_L = \frac{V_{CC}t} L ## b. I am bit confused when the transistor is "OFF" The point "A" is floating? The transistors and the diodes all the elements seem to be open is it correct? I am confused here.
  25. Truman I

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  26. PhysicsTest

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  27. X

    Engineering Find di(0+)/dt and dv(0+)/dt of circuit containing resistor, inductor

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  28. S

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  29. E

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  30. G

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  31. halleff

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  32. mcastillo356

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  33. mcastillo356

    What are the implications of considering infinite first derivatives in circuits?

    Hi I've attached the image of the circuit. My first thought before connecting it: if I connect it, I must consider the fact that current cannot circulate suddenly, because a sudden change in the amount of current should imply an infinite value in \dfrac{\Delta{I}}{\Delta{t}}, and a infinite...
  34. D

    Voltage and current as functions of time for a series RL circuit

    I already found ##I(t)## using Kirchhoff's laws, I got the equation ##V-RI-L\frac{dI}{dt}=0\Rightarrow L\frac{dI}{dt}=V-RI## then I solved the differential equation getting ##I(t)=\frac{V}{R}\left[1-e^{-\frac{R}{L}t}\right]##. My problem is founding the voltage as a function of time ##V(t)##, I...
  35. M

    Engineering AC circuit: Find the current through the inductor & capacitor

    Hi! I wonder if it is correct. Can someone confirm (maybe with a software) ? I(L) = I2 I(C) = I2 - I3 -- Thanks.
  36. J

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    I apologize using English fluently because I am not an Enlgish speaker. When I tried to solve this problem, I used current divider rule. So, $$i_o(t) = \frac{3}{3+5}*4e^{-2t} = 1.5*e^{-2t} A$$ However, This was wrong. The answer is $$ 1.5*e^{-2t} + 0.5 A$$ If I use $$V_O = L*\frac{di}{dt}$$...
  37. fight_club_alum

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    I calculated all the required in this problem correctly but can't understand why the sum of energy extracted and absorbed is not zero. They are: >0: 0J 0 <=E<=25: 4t^2 J 25 <= E <= 50: 4t^2 - 0.4t + 10 * 10^-3t J E > 50: 0 J Does that mean that an inductor stores energy even after there...
  38. tesla58

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  39. fight_club_alum

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  40. engnrshyckh

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  41. harsh22902

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  42. asadahmad_7869

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  43. D

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  44. J

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  45. J

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  46. A

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  47. C

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  48. Tesladude

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  49. Zack K

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  50. N

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