Inductance Definition and 495 Threads

  1. M

    Inductors and inductance and some other stuff

    Homework Statement A certain solenoidal inductor has a magnetic flux of 835 μWb through each loop of its coil when the current flowing through it equals 0.600 A. If the solenoid has 125 loops, what is its inductance? Homework Equations L = [(N)(magnetic flux)]/I The Attempt at a...
  2. R

    Inductance Formulas Homework: Find Emf & Time to Drop Below 1.25mV

    Homework Statement The current in a 4.70 mH inductor decays over time according to the following function, where t is in seconds. I(t) = (.943A) e-(396 s-1) t) (a) What is the induced emf across the inductor at t= 5.00 ms? (b) How long does it take the emf to drop below 1.25 mV?The Attempt...
  3. H

    What is inductance? i need a physical meaning and not equations

    what is inductance?...i need a physical meaning and not equations!
  4. M

    How to find value of inductance in LR series circuit?

    Hi. This is a question from my lab. I have a series of measurements of the voltage drop across a resistor for various frequencies with a constant voltage source in an LR series circuit. From these measurements I am supposed to calculate the value of the inductance "L". How can I do this?
  5. M

    Mutual Inductance in a solenoid

    Homework Statement A long solenoid (black coil) with cross-sectional area A cm^2 and length L is wound with n1 turns of wire. A time-varying current i1 flows through this wire. A shorter coil (blue coil) with n2 turns of wire surrounds it. Use (uo)(m*kg/s^2*A^2) 1) Find the value M of the...
  6. M

    Determine inductance of a solenoid

    Homework Statement Determine the inductance of a solenoid with 650 turns in a length of 21 cm. The circular cross section of the solenoid has a radius of 4.2 cm. Homework Equations ? The Attempt at a Solution I've looked all over my textbook and can't come up with a possible...
  7. A

    Inductance of a Rotating Machine

    Homework Statement The stator of the magnetic circuit of the above figure has a coil of turns 200, which carries a current of 1A. The rotor has a radius of 30mm, a height of 30mm and an axial depth of 20mm. The material for the stator and rotor has infinite permeability. The air gap...
  8. N

    Calculating Inductance in an RL Circuit

    Homework Statement An RL circuit has a 9.0 V battery and a 5.5 ohm resistor. When the switch is closed, the current in the circuit is observed to increase from 0 to 0.30 A in 0.17 s. A) What is the inductance? B) How long after the switch is closed does the current have the value 0.47 A...
  9. M

    Find Inductance: Lab Experiment & Graph Analysis

    Homework Statement Find the inductance L. This is for a lab experiment. For a resistor-inductor series circuit, I have a graph of a triangular input waveform from a generator and the voltage across the inductance, VL, as a function of time. I also have the value of the resistance R. The...
  10. R

    What is the Attempt at a Solution?

    Homework Statement If the outer conductor of a coaxial cable has radius 3.5 , what should be the radius of the inner conductor so that the inductance per unit length does not exceed 55 per meter? Homework Equations The Attempt at a Solution 1.385
  11. J

    Factors affecting inductance experiments

    I am about to do an investigation on the 'factors affecting inductance.' It would be brilliant if anyone had any ideas on experiments I could perform to investigate the factors affecting inductance. Thanks for your time.
  12. F

    Determine the value of the inductance ?

    Determine the value of the inductance ...?? Homework Statement Consider a series RLC circuit. The applied voltage has a maximum value of 210 V and oscillates at a frequency of 76 Hz. The circuit contains an inductor whose inductance can be varied, a 900 ohm resistor, and a 1 μF...
  13. F

    Finding the inductance of a coil

    Homework Statement A circular coil has a radius 0.10 m and 30 turns. An external magnetic field 2.60 mT is perpendicular to the coil. a) If there is no current, find the magnetic flux in the coil. b) When current = 3.8 A in some direction, there is no more net flux in the coil. Find the...
  14. S

    What is the Inductance of the Coil in a Radio Tuning Circuit?

    Inductance of the coil?? Homework Statement A radio has a tuning circuit consisting of a variable capacitor and antenna coil. IF the circuit has a maximum current when C=300pF and f=40kHz, what's the inductance of the coil?? Homework Equations f= 1/(2pi root (LC)) The Attempt...
  15. 1

    What is the Correct Calculation for Inductance in an LC Circuit?

    Homework Statement A circuit consists of a capacitor and an inductor. The resistance in the circuit is small and can be neglected. Initially, at t = 0 s, the voltage across the capacitor is at its maximum of VC = 10 V, the charge stored in the capacitor is 1 mC. It is observed that the...
  16. C

    Interesting Electromagnetic Inductance Problem

    So I've been working on this for a while now, but I'm a little stuck. I think I see how to solve the problem below, just need a couple tips to get me over the hurdle. Homework Statement There are two infinite wires in the same plane as a rectangular loop. Geometries are displayed in the...
  17. L

    Self and Mutual Inductance in a Toroid

    URGENT!: Self and mutual inductance Homework Statement 1http://img20.imageshack.us/img20/8531/asdasdasv.png a) Calculate L1, L2 and M for the coils in the following toroid (using thin toroid condition), the induced EMF in the second coil and the polarity. N1 = 500 N2 = 200 I1 = (20 +...
  18. E

    Inductance and Magnetic Fields

    I am working on determining the mH needed to produce a 250 gauss (0.025 T) magnetic field by a flat coil in a 8 ohm audio circuit that is PC controlled with an NHC tone generator. I need some help to do so as the information that I am able to get online does not allow me to make the jump from...
  19. R

    Engineering Mutual Inductance: Transformer AC Circuit Theory Questions

    Homework Statement http://img265.imageshack.us/img265/8616/43354308.png I have an exam coming up in a few days and I am doing some revision questions from some past exams and this is one I have attempted but I have no solutions to check my answers. The Attempt at a Solution using Vs = 12cos(...
  20. E

    Mutual Inductance: Homework Questions & Answers

    Homework Statement Homework Equations E=-M\frac{di}{dt} The Attempt at a Solution Can anyone even tell me what the heck this problem is asking? This chapter has been a nightmare and I don't understand any of it. The book is terrible and barely explains what 'mutual inductance'...
  21. E

    Why is the Time Constant Used in Solving Inductance Problems?

    This is not a homework problem, but practice. I have the answer. I need to know why. Homework Statement Homework Equations i=\frac{E}{R}(1-e^{\frac{-t}{\tau}}) "charging" an Inductor The Attempt at a Solution I have solved part a) correctly...
  22. D

    How Is the Self Inductance of a Solenoid Calculated?

    Homework Statement demostrate that the self inductance of a selonoid (L) that have: length = "l"; radius= "a" ; number of turns per unit of length= "m" , is:Homework Equations L = pi*(m2)*(a2)*Uo*[ ( (l2)+(a2) )1/2) - a ]The Attempt at a Solution It is suposse that the selfinductance is just...
  23. C

    How Does Inductor Behavior Affect Circuit Current at t = 0.224 s?

    pic : http://s982.photobucket.com/albums/ae310/christianerik/?action=view&current=untitled.jpg If the switch is closed at t = 0, find the current in the inductor at t = 0.224 s. Answer in units of A. & Find the current in the switch at that same time. I know that i must use i = V/R(1 -...
  24. C

    Inductance and RL circuits help

    If the switch is closed at t = 0, find the current in the inductor at t = 0.224 s. Answer in units of A. & Find the current in the switch at that same time. I know that i must use i = V/R(1 - e^-t/L/R) but can't seem to get the right answer. Any help is appreciated...5 ohms...
  25. S

    What Causes a Motor to Draw More Current Than Expected?

    Homework Statement A motor has both resistance and inductance. A motor rated at 1 hp input operating at 240 V draws 4 A of current because a. power is lost due to resistance b magnetic saturation robs power c. inductance does not consume power d. friction in the bearings of the motor e...
  26. S

    Mutual Inductance Homework: X & Y Coils | M Value

    Homework Statement A mutual inductor consists of two coils X and Y arranged so that one quarter of the magnetic flux produced by X links with Y. When X is used as the primary coil and Y as the secondary, the mutual inductance is M. What is the mutual inductance when Y is used as primary coil...
  27. D

    Mutual inductance as a psuedo-capacitor?

    Mutual inductance as a psuedo-capacitor? 1. I am testing how reduced the mutual inductance btwn two parallel ring-shaped inductors is when a material is placed btwn them. The primary coil is connected to an AC generator in series with an ammeter (on the order of mA), and the secondary in...
  28. S

    Mutual Inductance and Transformer Question

    Hi, I would like to ask a question about Mutual Inductance and Transformer. Suppose I have two coils N1 and N2, where N1 is the primary coil and N2 is the secondary coil that is connected in series with some resistance Rx. If I place a voltage V1 across the primary coil, the output voltage V2...
  29. J

    What is the Inductance of a Coil with Changing Magnetic Field and Current?

    Homework Statement An inductor has the form of a coil with 2074 turns and a diameter of 1.9 mm . The inductor is placed in a magnetic field perpendicular to the plane of the coil and increasing at a rate of 0.48 T/s . The current in the inductor is zero at t = 0, and then increases to 6.9...
  30. J

    Quick conceptual question about inductance

    Ok so i understand that after a switch in a circuit is closed for awhile the inductor acts like a battery, however, what happens after the switch is opened after being closed for awhile. A review question asks whether the energy: - is converted to sound and spark - remains stored in the...
  31. N

    Inductance in Kirchoff's voltage law

    Hi, when summing the votages when using Kirchoff's voltage law around some loop, why do anywhere they take L(dI/dt) as the voltage fall on the inductance (if we sum the voltage in the current direction)? If I understand well , if there is a current in some direction, the induced voltage...
  32. N

    Inductance in Ansoft Maxwell SV

    I need the inductance of a simple ferrite core wire-wound inductor. It's not clear how to get than in 2D Maxwell SV. The core is one material (ferrite), the windings are another (Copper). If you group them, the group must be of a single material, so no good. If you don't group them...
  33. T

    Inductance and capacitance quick question

    Homework Statement Hello I am studyin for a test and I just wanted to make sure I understand this basic idea... All C's are 5 micro F All L's=2H Homework Equations The Attempt at a Solution For the I came to the conclusion that Ceq=5 micro F the ones circled in blue...
  34. A

    A doubt on self inductance and mutual inductance

    i am having a doubt that when we find a expression for mutual inductance we say that flux change in primary coil induces emf in secondary coil. but why change in flux doesn't induce any current in primary coil also.
  35. N

    Where Does the Self Inductance Formula Come From?

    http://i27.tinypic.com/23r02mg.jpg I CANT UNDERSTAND FROM WHERE THEY GET THE FORMULA IN THE SOLUTION
  36. N

    Why is the formula for magnetic field not divided by length in this image?

    http://i26.tinypic.com/250tkyh.jpg the formula for magnetic field is like they show but its not divided by l like they did i can't see a reason why they present it that way ??
  37. N

    The logic of the self inductance formula

    M_{12}=\frac{N_2\phi _{12}}{I_1} i need to remmeber it but i can't see the logic of the formula ??
  38. M

    How Is the Inductance of a Solenoid Calculated?

    Homework Statement A constant current of 1A through a solenoid creates a magnetic flux of Φ=20mWb measured on the solenoid axis in the middle of the solenoid. What is the value of the solenoid inductance? Homework Equations here's what I've managed to find on the subject...
  39. M

    Can a Toroidal Inductance Generator Really Output Five Times Its Input Energy?

    Ive made an experimental generator built loosely of the Faraday flashlight technology. Rather than a linear air coil using a reciprocating magnet I've made a toroidal coil and added magnets on the outside of the toroidal to coerce unidirectional movement of the interior magnets that match the...
  40. J

    Mutual Inductance (Two coils connected in parallel to source)

    Hi, I recently performed a stator core loop test and am now in the process of capturing the setup and results in a report. A short explanation of the test setup and execution: A cable is wrapped around the core and energized, which induces a magnetic flux through the core. The core...
  41. C

    What is the Induced Current in the Second Coil?

    Homework Statement The mutual inductance between two coils is 0.0100 H. The current in the first coil changes uniformly from 2.7 A to 5.0 A in 0.160 s. If the second coil has a resistance of 0.600 Ω, what is the magnitude of the induced current in the second coil? Please show stepsHomework...
  42. B

    What size inductance for a flyback transformer?

    I'm looking over some equations for the output of a flyback transformer (essentially the same as for a buck-boost converter) and I notice that as long as the flyback operates in the continuous mode, the inductance doesn't enter into the equation. Of course since no inductor is ideal, there must...
  43. A

    Calculating Inductance Gradient for EM Launcher

    The equation widely used to calculate the force on a projectile in an electromagnetic launcher, more specifically a railgun, is: F = 0.5 * L' * I^2 where: --> F is the force in Newtons --> L-prime is the inductance gradient of the rails in henries/meter (H/m) --> and I is the current...
  44. Y

    Inductance in an AC generator.

    I just have some confusion about whether or not self-inductance will occur in an AC generator. The current is alternating in both direction and magnitude rapidly when it is generated and this will in turn cause a changing magnetic field around the conductor. This magnetic field will then...
  45. G

    Help with Inductance Homework: Calculate from 84V, 80kOhms & .5355mA

    Homework Statement A inductor that has a resistance of 80 k-Ohms is connected to an ideal battery of 84V. 0.8 milliseconds after the switch is thrown the current in the circuit is .5355 mA. Calculate the Inductance. answer in units of H. Homework Equations V = L(I/t)? The Attempt...
  46. B

    About infinite inductance, zero capacitance

    Hi Friends, :smile: Two particularly abstract queries have surfaced in my mind (this seems to be a recurring problem with me! ) :biggrin: CASE 1 :- Infinite Inductance Let us consider an 'ideal' solenoid coil (zero resistance, pure inductance). It is connected to an AC supply of say...
  47. D

    Engineering Help with Circuits Capacitance & Inductance

    The images tell it all. Please help someone. http://image.cramster.com/answer-board/image/200941884006337564080009162509346.jpg on this diagram, the expression IL(t) should read I(t). http://image.cramster.com/answer-board/image/2009418845296337564112974787505740.jpg
  48. B

    Mutual Inductance in a circuit

    If there is a circuit consists of a long thin conducting shell of radius a and a parallel return wire of radius b on axis inside. If the current is assumed distributed uniformly throughout the cross section of the wire, must we calculate mutual inductance?
  49. G

    Calculating Inductance for 10kHz Capacitor

    Homework Statement What inductance must be used with a 4.0 µF capacitor to produce a frequency of 10 kHz, which is near the middle of the audible range of frequencies? Homework Equations w = 2pi*f/C=1/(sqrt(T*C)) --->angular fequency T= 1/f The Attempt at a Solution T= 2pi/w...
  50. S

    Mutual inductance using bessel function

    Hi, I am en electrical engineering grad student and I have to solve an equation to calculate the mutual inductance between an antenna and a micro-inductor. I think it is a Bessel equations but I don't know how to solve. M(a,b,d)=(1.45x10^-8)*integral(J1(1.36x)*J1(0.735x)*exp(-x-13.6))dx...
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