What is Inductance: Definition and 494 Discussions
Inductance is the tendency of an electrical conductor to oppose a change in the electric current flowing through it. The flow of electric current creates a magnetic field around the conductor. The field strength depends on the magnitude of the current, and follows any changes in current. From Faraday's law of induction, any change in magnetic field through a circuit induces an electromotive force (EMF) (voltage) in the conductors, a process known as electromagnetic induction. This induced voltage created by the changing current has the effect of opposing the change in current. This is stated by Lenz's law, and the voltage is called back EMF.
Inductance is defined as the ratio of the induced voltage to the rate of change of current causing it. It is a proportionality factor that depends on the geometry of circuit conductors and the magnetic permeability of nearby materials. An electronic component designed to add inductance to a circuit is called an inductor. It typically consists of a coil or helix of wire.
The term inductance was coined by Oliver Heaviside in 1886. It is customary to use the symbol
L
{\displaystyle L}
for inductance, in honour of the physicist Heinrich Lenz. In the SI system, the unit of inductance is the henry (H), which is the amount of inductance that causes a voltage of one volt, when the current is changing at a rate of one ampere per second. It is named for Joseph Henry, who discovered inductance independently of Faraday.
Homework Statement
A 0.100m long solenoid has a radius of 0.05m and 15000 turns. The current in the solenoid changes at a rate of 6.0 A/s. A conducting loop of radius 0.0200m is placed at the center of the solenoid with its axis the same as that of the solenoid. Determine the mutual...
Homework Statement
hi, i just have few questions on how to make a 30mH-inductor (solenoid). I have an enameled copper wire which i will wrapped into a 7-inch rebar having 12mm diameter. In order to determine the number of turns, i made some calculations:Homework Equations
L=(uAN^2)/dThe Attempt...
Homework Statement
calc the self inductance of a hairpin...to get a definite answer assume the wire has a tiny radius of e
Homework Equations
L=\phi/I
The Attempt at a Solution
So i found the b field \muI/2\pis
than for the flux, I got \muI/2\pi\int1/s Lds
In the book, they got...
Homework Statement
A long straight wire of radius r=a carries a current I uniformly distributed over its cross section. Show that the magnetic energy per unit length (energy density u=B^2/2mu) is given by \mi_{o}\ =\ 4\pi\ \timesI^2\ 10^{-7}/16pi. What is the contribution that a single long...
The energy of an RLC circuit decreases by 1.00% during each oscillation when R=2.00 ohms. If this resistance is removed, the resulting LC circuit oscillates at a frequency of 1.00 kHz. Find the values of inductance and capacitance.
Is there a difference in inductance of an inductance with magnetic material whether it is magnetized or not. Meaning is there an increase of inductance if the core has been magnetized ( become magnet) vs the same material but not magnetized?
Does magnetization increase the \mu of the material?
Homework Statement
Calculate the self inductance of a solenoid that is tightly wound with a wire of diameter .1 cm , has a cross sectional area of .9 cm2 and is 40 cm long?
Homework Equations
The Attempt at a Solution
the formula L=u0n2V where V=volume and n=number of turns...
the problem given is:
A circular loop of wire can be used as a radio antenna. If a 22.0-cm-diameter antenna is located 2.20km away from a 95.0-MHz source with a total power of 55.0kW, what is the maximum emf induced in the loop? (Assume that the plane of the antenna loop is perpendicular to the...
I'm not really sure where to put this question.
I'm trying to project current output of a ciruit I am building. Suppose that an initial current which pulsates according to time, t, is given as I = sin(wt)+1. I have two inductors which share the same core in close proximity, the first having...
Homework Statement
I am attempting to work out the mutual inductance between a pair of single-turn coilds attached to a transmission line.
Single-turn coils :inner diameter d, thickness H1
Transmission line: distance between plates d and the parameters L,H2,\delta,\beta and angle \alpha
I...
Homework Statement
The capacitors are charged to a potential V1 and V2. The self inductance of coils are L1 and L2. The mutual inductance is M. Analyze the dynamics of the circuit.
Homework Equations
The Attempt at a Solution
I wrote down Kirchoff's Loop Law (or Voltage Law) to...
I am confused on the formulas of inductance.
In "Fields and Waves Electromagnetics" by David Cheng:
L = \frac{\Lambda}{I} \;\hbox{ where }\; \Lambda = N \Phi
N is the number of turns on the inductor, \Lambda is called flux linkage and
\Phi = \int_S \vec B \cdot d\vec l...
Hello,
I need to construct an AM radio's RC circuit that:
1. resonates to frequency f= 580 Hz
2. has a maximum current of I = 0.2 A
3. the capacitor has a maximum potential energy U = 2 x 10^-5
I need to find: The inductance and capacitance (L & C) of this RC circuit.
Please help...
My old freshman physics text defined inductance as flux/turns, which applies only to solenoids. This seems like a pretty weak definition since any length of wire in any geometry has some inductance. There has to be a more general definition.
My first guess was that L could be calculated from...
I am designing a loop antenna and would like to calculate the inductance. The radius of the loop is 6.67 centimeters, the radius of the wire is .42mm (#26 awg) and has 57 turns.
Using the following formula
L =N^2*R*mu_o*mu_r*(ln(8R/r)-2)
where N=turns, R=loop radius and r=wire radius. From...
I am trying to design UHF quadrature couplers from the following references:
[1] 'Broad-Band Twisted-Wire Quadrature Hybrids' , http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1127996
[2] 'Twisted wire Quadrature Hybrid Directional Couplers' QST Vol 63 January 1978 pages 21-23...
Homework Statement
A single rectangular loop is placed distance C from a wire of current I. The dimensions of the loop are BxA.
The loop and wire both lie in the same plane, and a is at right angles to I.
Derive an expression for the mutual inductance, given that you found flux in a previous...
Hello, I need help with calculating inductance of a toroid core. I tried googling and came up with 3 results, but they don't really help. Links are:
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/indtor.html
http://www.nessengr.com/techdata/toroid/toroid.html...
Homework Statement
An electric motor draws a 1A (rms) from the 230V (rms) mains. and is found to shift the phase of the 50Hz alternating current by 30% of the period. What is the self inductance of the coils in the motor?
Homework Equations
The Attempt at a Solution
i've started...
Homework Statement
Pulsed lasers used for science and medicine produce very brief bursts of electromagnetic energy. If the laser light wavelength is 532 nm, and the pulse lasts for 37 ps,
(a) how many wavelengths are found within the laser pulse?
(b) How brief would the pulse need to be to...
When finding for "L" is the value for "l" (length of coil) affected by the length of the core material. Or more specifically when one is working this equation for two coils yoked in series do you figure each coil separately?...and if NOT, do you include the length of the yoke?
Here is a link...
Homework Statement
The oscillator of a 96.9 MHz FM station has an inductance of 1.4 μH. What is the value of the capacitance?
Homework Equations
I haven't the slightest idea. I've looked through the section in my physics book and looked all over online and I can't find anything.
The Attempt...
Hi everybody, i have got a question,any help will be much appreciated
A ferrite ring core has a slot cut in it such that the plane of the slot contains the axis of the toroid. It is wound with 26 turns.
i have attached the picture of the this problem.
Relative permeability = 680
Bsat...
If I have a trace on a PCB that is wider on the left side and then tapers down to a narrower trace on the right side, why is it that the inductance is greater on the narrower side? I realize there are equations that describe this behavior but I'm just trying to get a qualitative understanding of...
Hi everyone. I was wondering about something I just read with wireless energy transfer and resonant energy transfer on Wikipedia.org. What if you send a large amount of ultrasound tuned to a certain frequency over the AC/DC outlet plug. Would it get to the Transformer? Would the transformer's...
Homework Statement
I have posted my complete question http://imagebin.org/110458" [PLAIN]http://imagebin.org/110458. It is about a DC circuit with an inductor and a static magnetic field applied on a part of the circuit loop. An expression for the transient current needs to be found. My...
Consider a solenoid which is almost toroidal, with a few turns missing (say you have 1000 turns on 99% of the circumference of the toroid) - they will form the primary winding. Let us have 10 turns on 1% of the circumference of the toroid - they will form the secondary winding. Since practically...
According to widely known formulas, the inductance of a long straight solenoid will remain practically the same if we bend it into a toroidal solenoid. It seems to be a contradiction, because the magnetic path length of a straight solenoid is more than two times greater.
NOTE: This is not a homework problem, so do not shift it.
The question is as follows, I am given a core having an air gap wounded by a coil, I am given area of core, gap. Length of core and gap. number of turns. Permeability of core and air gap and magnetic field in the core (I assume no...
I posted this question a few months ago, but got no responses, especially after it got moved to the homework help forum. Since then, I have asked several professors, many of whom I expected to be experts in this area, and I've been given several different shaky sounding responses. So, I'd like...
Consider two solenoids, an often familiar formula for the induced emf from 1 solonoid in the 2nd solenoid is [PLAIN]http://http://www.mediafire.com/?ymfmhzjgqkgenjz. My question is.
Doesn't this only account for the emf induced in solenoid # 2 from solenoid #1, and not the emf induced in...
Can anyone explain the concept behind changing of inductance of a solenoid (when AC current is passing through solenoid) on moving a metal sleeve (hollow metallic pipe) over the solenoid enclosing the solenoid.
I've been working my way through an old scientific paper on inductance calculation, and there's a fundamental principle I'm having a problem with.
Suppose there are two filamentary conductors of any arbitrary shape. Now consider an infinitesimal element dl1 somewhere on the first conductor...
I have a very basic question regarding mutual inductance.
Consider a basic square loop with two coils wound on opposite sides from each other, with coil one excited while coil two si left open circuited. The total flux linking coil 1 is
Φ11 = Φl1+Φ21
where
Φ11 is the total flux...
I was recently given a problem I can't quite wrap my head around. Here's the situation:
shttp://pics.bbzzdd.com/users/theman/inductorbulbs.gif
(you'll have to copy the link, - the s, into your address bar)
Oh-- and i just realized a mistake with the drawing, the dots should be x's to...
I've got the probem with determination the formula of inductance in the toroidal coil.
This coil has a shape of toroidal shell (like one torus inside the second).
1 torus: (x-R0)^2-y^2=r1^2
2 torus: (x-R0)^2-y^2=r2^2
The shell is a magnetic material with given permeability "ur".
The...
i am having trouble with finding inductance and capacitance of a cylindrical shell with gap.
say inner radius is a, outer radius is b, and filling dielectric between a and b,
and its not a exact circle which have a small gap say d. its like a split ring but only one shell.
How can i...
Hi,
Hope this is the right forum to ask this question.
I have an electric fence running parallell to an electrified railway (25kV@50Hz, varying current). I'm trying to figure out how to calculate the induced voltage on the fence to figure out how long the fence can be before it becomes...
I have to figure out the two inductance values for a transformer; L2 and L1 where L1 is the inductance that sees the primary voltage and L2 is the secondary.
i'm working with the formulas;
n^2 = Z2/Z1 (8/1000)
roeL2>>Z2 (roe= angular freq= 1kHz)
n^2= L2/L1
basically i use this...
Homework Statement
ok, i have one loop that has a current source (given as a phasor), a resistor R1, and an inductor L1. in the other loop there is an inductor L2 and resistor R2. something like this:
src resistor dot + (V1) (V2)+
*loop1*...
Homework Statement
So, I have a problem where I have two concentric current loops. The final statement in the problem is: "estimate the mutual inductance between loops if the positive direction of current is the same for both loops."
If the currents of the loops are the same direction, how...
While working on a project I noticed something wonky and I don't understand how or why it is happening.
Typically if I have an inductor, the presence of a permanent magnet will reduce the inductance according to its distance - however I have started using a type of nanocrystalline core that...
Homework Statement
One solenoid is centered inside another, The outer one has a length of 50cm and has 6750 coils, while the coaxial inner solenoid is 3cm long and 0.12cm in diameter and contains 15 coils. What is the mutual inductance of these solenoids?
Homework Equations
M=N1\phi1/I2...
Hi all,
The situation is this: I need to calculate the self inductance of two solenoids wired in series, of equal radius and a given separation d. They are coaxial. The length h of each is known.
Most double-solenoid references I found looked at the mutual inductance, and not the...
Homework Statement
Hello,
I am currently doing an investigation to study the factors affecting inductance. The three variables i am using are the number of turns on the coil, the material of the core of the coil and putting 2 cores in series/parallel to see how this affects the inductance...
Homework Statement
A typical "light dimmer" used to dim the stage lights in a theater consists of a variable inductor L (whose inductance is adjustable between zero and Lmax) connected in series with a lightbulb. The electrical supply is 120 V (rms) at 60.0 Hz; the lightbulb is rated as 120...
ok, let's say we have a battery connected to a resistor and an inductance in series
-|battery|+______ 00000(inductor)______resistance(R)
if the rate of change of current is decreasing , then the induced EMF in the inductor would be towards the right? because they would want to strengthened and...
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...