Coil Definition and 864 Threads

I need to calculate how much voltage is created as a magnet passes over a coil. However I don't know a formula to calculate this. Could anyone help me, I just need a formula PS: sorry, spell check does not work

The idea is as it follows: We have an homogeneus magnetic field that was increased from 0 to Bf. It induced a certain current (that accumulated to a charge Q) in a circular coil of radius a and resistivity \rho constant. The question is, what would be the charge Q' when the coil is twisted...

See attached problem: http://img72.imageshack.us/img72/4791/65321158jp4.th.jpg The answer is 6.9 × 10−4 Wb - by multiplying the Area by the magentic flux density. Mq is, why does one not multiply this by 850 (number of turns) in order to find the answer. Thanks

Consider a toroidal coil of rectangular section of N turns, for every one of which circulates a stream I. The inner radius of the coil is a and b is the exterior and the height is h. The core of this coil is a material inhomogeneous in such a way that their magnetic permeability just depends on...

I would like to know..what is the concept of rotating a magnet above a coil of wires to produce electricity.. what is the factor affects the power of electricity produce.. 1)Is it the number of coil? 2)is it the power of magnet? 3)is it the distance between magnet and coil 4)or anything...

Homework Statement A solenoid of cross-sectional area 2*10^-4 m^2 and length 0.5m having 500 turns is to be used to produce a uniform magnetic field some distance close to the center of the solenoid. Find the current that must flow in the solenoid to produce a magnetic flux density of 3*10^-3...

Hi.. I have a question about AC magnetic field, wondering if you can help me understand this. For a DC solenoid coil, We can say Magnetic field H=N*i/L (simplest form) For an AC input, H=N*isin(wt)/L ; H(rms) = N*i/L (i is RMS value) As long as the current i-rms is kept constant...

I want to calculate the electrical parameters of solenoid coil of a valve for a given spring force. I know the force required to pull the solenoid plunger through a given distance against a spring, is there any formula to find out the required voltage, number of turns of coil winding & current .

Homework Statement How will a coil's self inductance change if you unwind it and then re-wind half of the length of wire into a coil with the same diameter but with half of the number of turns? The answer is that it will decrease by 1/4, but I don't understand why it isn't 1/2 instead...

Tesla Coils! How many here have built Tesla Coils? I am wondering becouse i am currently building my seconed Tesla Coil. (My first one barly worked, pretty much made out of hot-glue) And I'd like some group to dump all my questions on, only other forums I know of to post questions...

I am a student at Colorado State. Can someone in this forum help me with building an AC coil either an air core coil or C-frame iron or steel with so many turns of copper wire that has a maximum magnetic field of 0.2 T and its frequency range is 100KHZ to 100MHZ. I am searching on the internet...

Homework Statement This is part of a lab I did, I am working on the writeup now. We placed a coil of wire inside of a Helmholtz pair, with 20V of 60Hz AC through the Helmholtz pair. The coil inside was connected to an oscilloscope and the induced voltages were recorded. I now need to...

Hi I am working on a project to do a coil simulation using COMSOL to determine inductance and resistance variations with frequency. I have a CAD file for the geometry but I need help because I am having serious difficulties with the rest. Can anyone help pls? thanks alot

Homework Statement A coil with 170 turns, a radius of 5.0 cm, and a resistance of 12 ohms surrounds a solenoid with 230 turns/cm and a radius of 4.7 cm; see the figure. The current in the solenoid changes at a constant rate from 0 to 1.8 A in 0.11 s. Calculate the magnitude and direction of...

Hi, i am working in a motion capture project one of its parts is a sensor i need a formula of the voltage generated in the coil due to moving in electromagnetic Field from an inducer i think it depends on ( B , cosθ , µ , N , L , r ) i post this thread in another forum but no one answer...

Homework Statement A 32 turn circular coil of radius 4.60 cm and resistance 1.00 is placed in a magnetic field directed perpendicular to the plane of the coil. The magnitude of the magnetic field varies in time according to the expression B = 0.0100t + 0.0400t2, where t is in seconds and B is...

induced emf in secondary coil - help ASAP Please Homework Statement A very long, straight solenoid with a cross-sectional area of 6.00 cm2 is wound with 40.0 turns of wire per centimeter, and the windings carry a current of 0.250 A. A secondary winding of 2.00 turns encircles the solenoid...

Homework Statement A solenoid has 235 turns of wire wrapped along its length of 27 cm. The diameter of the solenoid is 1.5 cm. In the middle of the solenoid is a smaller coil of diameter 1.0 cm with 50 turns of wire along its 2.0 cm length. The two coils are coaxial. A current of 15 A is in...

Homework Statement A 1.88 m long wire carrying 3.1 A is wound into a tight, loop shaped coil 0.05 cm in diameter. What is the magnetic field at its center? Homework Equations The Attempt at a Solution I use Ampere's law but i get the wrong answer. I think i did not set up the...

First of all, this is not homework (before anyone suspects). I'm just doing this out of hobby and expanding my education. I've been trying to come up with distilled expressions for force on a magnetic dipole , anywhere in space around a simple coil. I started out with these expressions...

Homework Statement A 20 turn circular coil of length 5.9 cm produces a magnetic field of magnitude 1.9 mT at its center. Find the current in the loop Homework Equations B=(moconstant)nI where n is the number of turns per unit length and I is current. magnetic field is B The...

how to not short circuit an induction heating coil Just wondering about induction heating coils and how to not short circuit one. basically, if i hook up one end of the coil to the positive and one end to the negative (DC) i assume that i will be short circuiting the connection and also...

Torque on a soleniod / coil in magnetic field Homework Statement A solenoid having 180 turns and a cross-sectional area of 6.68 cm2 carries a current of 1.12 A 1) If it is placed in a uniform 1.12 T magnetic field, find the torque this field exerts on the solenoid if its axis is...

Homework Statement You have a 1.2-m-long copper wire. You want to make an N-turn current loop that generates a 0.60 mT magnetic field at the center when the current is 1.5 A. You must use the entire wire.Homework Equations What will be the diameter of your coil? The Attempt at a Solution...

I'm just wondering about what benefits there are to building / using an induction coil as opposed to other devices to create devices for spark gap experiments. I am referring to the induction coils with a primary winding and secondary windings with enormous numbers of turns - similar to...

When a DC coil (relay) is denergized, shouldn't the collapsing field cause a current that would oppose the change in current? Wouldn't that induced current be in the same direction as when the coil was enegized? Not seeing how a freewheeling doide gets forward biased. If I apply Lenz Law...

My situation is this. I have 6,560 ft (4 lb) of polyurethane-nylon coated #27 gauge round wire wound in a coil with an air core of 1 1/8 in. wide x 4 in. long x 4 in deep. I don't want to destroy my precious electromagnet so I'm afraid to give it some current. What would happen if I attached a...

Using a PMs' field and inducing a primary coil which is coupled with an independent coil of equal configuration to the primary. Would this secondary flux field be opposite and of equal EMForce? If so, Equal to the PMs' strength or the primarys' EMForce? Thanks Robin07

Hey fellas, I blundered onto this forum trying to figure out the value of a coil. I'm building a hydrogen generator and the plans call out for hand winding a toroid coil. I'd like to buy one instead but it doesn't give the value of the finished coil, just how to make it. It tells you to use...

Homework Statement A rotating coil is a common device for measuring magnetic fields. Consider a coil of area A and N turns that is rotated at angular frequency w in a magnetic field. The position of the coil is adjusted so as to produce a maximum induced current Imax which can be measured by...

Homework Statement A circular coil, with radius of 10 cm, and 25 turns, rotates in a constant magnetic field of strength 2.4 T, with the axis of rotation perpendicular to the direction of the magnetic field. (a question about finding the induced voltage- 5.92 V) part C. If the...

Homework Statement The picture shows (there's supposed to be a pic) a Helmholtz coil consisting of two circular coaxial coils, each of 200 turns and radius R = 25.0 cm, separated by a distance s = R. The two coils carry equal currents i = 12.2 mA in the same direction. Find the magnitude...

Hi everybody, I need to indirectly measure the high voltage across a wire, which is one of the leads to a spark gap. I ran the wire through a coil inductor(air core) and measured the voltage across the coil leads with an oscilloscope when i get the spark. I also connected a resistor in series...

hi i ned a little help with this problem please. An object is connectedto a 100 coil spring, that is hanging from the ceiling. The spring stretches by 0,160m. What is the spring constant? Im not sure how to go about with this...is the force 100? please help. Thanks

Homework Statement A 21.8 cm diameter coil consists of 18 turns of circular copper wire 1.70 mm in diameter. A uniform magnetic field, perpendicular to the plane of the coil, changes at a rate of 8.15E-3 T/s. Determine the current in the loop. Homework Equations V=IR V=B/T * A * N...

Homework Statement The sketches below show a circular coil and a permanent magnet; the arrows indicate both the magnitude and the direction of the velocities of the magnet and coil. In which situations will the induced voltage (and hence the current) in the loop be zero? (Enter your answer...

Homework Statement A rectangular coil of 150 turns has dimensions of 23 x 70 cm and is located in a uniform 3 T magnetic field. In 1.2 s, the plane of the coil is rotated from a position where it makes an angle of 15° with the magnetic field to a position where it makes an angle of 72°...

What is the magnetic field at the center of a 60-turn coil carrying a current of 4 A, if it has a radius of 0.2 m? I was thinking of using the equation B=(mu0)(N/l)(current) But I was wondering do I use the radius for l or do I use the diameter?

Homework Statement A narrow flat coil wound on a square frame has 160 turns and sides of 34.0 cm. It carries a current of 5.30 A and is positioned in a 0.260- T magnetic field. What is the maximum torque that can be exerted by the field on the coil? Homework Equations Torque = (Number...

Homework Statement A coil with magnetic moment 1.40 Am^2 is oriented initially with its magnetic moment antiparallel to a uniform magnetic field of magnitude 0.830 T. What is the change in potential energy of the coil when it is rotated 180 degrees, so that its magnetic moment is parallel...

hi everyone, I have a problem, if U see the photo I have coil which carries current of rectified ac waveform through it. I have sludge(Steel rod of weight 20#) which has to be moved till the centre of the coil. If the current in coil induces magnetic field to sludge to move upward, then...

Im trying to find out the difference. It seems that an ignition coil converts the cars battery voltage from 12V to several thousand volts; whereas, a magneto creates several thousand volts without any input from the aircrafts battery.

Hello peoples. Im attempting to build a van der graaf generator and a small tesla coil. Hopefully I have come to the right place for help. Firstly I'll start with van der graaf generator. I am going to use pvc lower roller (negative charge) and nylon upper roller (positive). any suggestions...

Homework Statement The photograph shows a transformer which has been cut in half. The transformer consists of primary and secondary coils wound around the same laminated iron core. The diagram shows a cross-section of the iron core and the two coils. One coil consists of a few turns of thick...

[SOLVED] A Multirange Coil Ammeter Galvonmeter (?) resistance question Homework Statement A Multirange Ammeter. The resistance of the moving coil of the galvanometer G in the figure (See Below) is 48 Ohms, and the galvanometer deflects full scale with a current of 0.0200 A. When the meter...

MMC for Tesla coil, inquery... Hello all, Every project of mine starts like this... I first need to consider my budget. So, I am wanting to build a Tesla coil. I can get everything needed for this, but I have concerns about the primary capacitor. As I have looked all about the internet...

Homework Statement 1.) Problem (exam question that I got wrong and want to figure it out) A circluar coil of radius a=.35m rotates at a frequency of 120 hz in a constant magnetic filed of B=.8T. The axis of rotation is perpendicular to the field the coil has N =340 turns it has a resistance...

I have a very limited budget right now. How much do you think it would cost to build a small Tesla Coil? This would include buying the components of a Tesla coil.

A coil with 240 turns enclosing an area of 13.7 cm^2 is rotated in a time interval of 3.70×10^-2 s from a position where its plane is perpendicular to the Earth's magnetic field to one where its plane is parallel to the field. The Earth's magnetic field at the lab location is 5.9×10−5 T ...

Hi everyone, (nb: I posted this in the introductory physics section, but maybe it should be here? I'm not exactly sure how to divide physics into introductory and advanced. I hope this isn't against the rules - it's only my second post!) I am trying to understand my EM course again, and I...