Coil Definition and 864 Threads

When this guy gets inside the Faraday cage and they hit it with like 200,000 volts from a Tesla coil , when he is inside the cage he can touch the inside and not get shocked , so basically the charge flows on the outside , is this because the electric field from all around the circle pushes...

Hello everyone: I am trying to find a program or formula that will help me figure out how many windings, turns of coil, are needed per coil on a 6 coil steel stator ring powered by 3-phase AC power to get a certain magnetic field strength, about 1.3T. Is there any way that you could help me...

Homework Statement What is the induction in the centre of a spherical coil with N turns, the current I and the radius R? Homework Equations Biot-Savart law \mathbf{B} = \int\frac{\mu_0}{4\pi} \frac{I d\mathbf{l} \times \mathbf{\hat r}}{|r|^2} The Attempt at a Solution I know what...

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...

We determined the constants R and L of a coil by placing it in series with a standard resistor of 10 ohms and reading the voltages on the terminals of Rs, the coil and the series circuit complete. What are the values of R and L for the following voltage readings at 60 Hz: Vrs = 20; Vcoil =...

Hello ! I am using Comsol Multiphysics in order to simulate the eddy currents in a damaged/cracked steel circular rod, with a helix coil surrounded it and thus creating the alternativ magnetic field. Actually, I am having a lot of problem in modelling it, mainly because I am new in using...

0. Bit o' background + greeting Hello everyone. I am a third-year math/physics/CS/AI major and I've never used this forum before, as can be seen from my impressive post count. I enjoy leafing through it though and find myself perpetually impressed by the activity and commitment of the community...

Homework Statement A problem from a translated Sears-Zemansky, 1965, 14-10: A conduction coil with inductance of 15 miliHenrys and resistance of 10 Ohms, is connected in line with a capacitor of 200 microFarads and a resistor of 12 Ohms. The circuit is supplied with an alternating current of...

A square loop of wire of side a is rotating with frequency \omega in a magnetic field. I understand that at time t, a magnetic field B=B_{0}sin\omega t passes through the loop. But why does the current induced in the loop vary twice with the frequency of rotation? What is the expression of...

Hi all. I'm just wondering if it is possible to calculate the resistance in a coil without the amperage value? I've got voltage,coil-diametre, amount of turns, coils material type. The only way i think it is possible if i set a ampmetre into the circuit. is there any way? Thank you.

Homework Statement 200-turn,coil of 8.0cm length is made of 0.50mm-diameter copper wire. Magnetic field is perpendicular to coil. At what rate B should increase to induce a 2.0 A current in the coil? Homework Equations The Attempt at a Solution i am not getting anthing

Homework Statement A flat square coil of N turrns and area A is rotated at an angular velocity w in a uniform magnetic field of strength B. The rotation axis is perpendicular to the magnetic field direction. The coil is connected to a Galvonometer using suitable slip ring connectors and the...

Homework Statement a conduction coil with 2 resistors are connected, according to the drawing. write the expression for the potential difference Vac over the coil after t seconds after the switch is closed. Homework Equations The current at any time: (a) i=I(1-e-Rt/L) The electro motive...

Homework Statement Hooking up voltage to a solenoid (coil of wire) creates an electromagnet. Moving the electromagnet in and out of a larger coil hooked up to a galvanometer creates an emf (voltage) in the larger current. Does an emf get created for a *stationary* electromagnet inside a...

Hi, I am not so good with magnetic equations and I am needing some advice in how to start to calculate the magnetic flux generated by a motor coil. Finally I want to be able to calculate the magnetic flux generated with and without the iron core of each coil in the motor. I will...

This is not a homework. I am just pretty confused about a problem (with solution!) I saw in the internet found here: http://www.transtutors.com/physics-homework-help/electromagnetism/Electromagnetic-induction.aspx The part I am confused is the mutual inductance part. Here I repeat the question...

Homework Statement The diagram illustrates a Helmholtz coil, consisting of two identical circular coils of wire, each one having N loops and carrying the same current I. The radius of each coil is R, and the two coils are R meters apart. (a) What are the direction and strength of the...

I am just an electrician doing experimental work with a Stubblefield coil. From what I've read the most common steel is 1018. If Stubblefield used a common bolt I assume this would fall into the 1018 realm. Would the 1018 iron core be better cold rolled or hot rolled for the magnetic collapse as...

Homework Statement The question is Jackson's 5.35. Insulated coil on a sphere (radius a) to generate uniform field B0 in the z-direction inside the sphere and dipole field outside the sphere. Conductivity is \sigma and permeability is \mu. 1st question is to find the surface current K and...

When placed in series a coil and capacitor resonate at a frequency of 2251Hz and when placed in parallel they resonate at a frequency of 2228Hz. At parallel resonance it is also found that a current of 5mA flows from the supply when the supply voltage is 25V r.m.s. Determine the value of the...

1. A 100-turn, 2.0-cm-diameter coil is at rest in a horizontal plane. A uniform magnetic field 60 degrees away from vertical increases from 0.50 T to 1.50 T in 0.60 s. 2. EMF = N*d(phi)/dt phi = flux = ABcos(theta) 3. dB/dt = 1/0.6 EMF = 1000*(1/0.6)*pi*r2*0.5 = 0.262 V Is...

Homework Statement A solenoid with a length of 25.0 cm, radius 1.60 cm and 5500 turns carries a current of 1.50 A. A small coil of radius 1.05 cm and 130 turns is placed at the center of the solenoid with its axis in the same direction as that of the solenoid. A 470 ohms resistor is connected...

Homework Statement A generator consists of a circular coil of radius 0.2 meters wrapped 10 times and is spun in a uniform magnetic field of 0.38 Tesla. It is connected (on the primary side) to a transformer with 7 turns on the primary side and 20 turns on the secondary side. If the secondary...

hiii guys im doing my FYP on amplify the voltage from a rogowski coil just to make it short i have already design the coil which can detect a 50k frequency and gives pick-to-pick = 10mV Ac now, i have to design an amplifier that can give an actual value. so, i have already got a...

Hello everybody! :D Im building a tesla coil for a science fair and needed some help with it. For the toroid, I got a rubber pipe which I intend to bend to a toroid and wrap with aluminum tape. Will this work? How will it be different if I use a metallic sphere? Also, for the spark gap...

If anyone can advise that would be great. 1. The plane of a 5 turn coil of 5mm² cross sectional area is rotating a 1200 r.p.m in a magnetic field of 10mT. Q. Calculate the amplitude of the induced voltage across the coil Data: 5 turns c = 1200 rpm A = 5cm² B = 10 mT 2. φ =...

Homework Statement A current of 22 amperes flows in a heater coil whose resistance is 5 ohms. What E M F in volts is required? Homework Equations The Attempt at a Solution Not quite sure where to begin. I'm thinking the internal resistance, R, is inherent w/the circuit so EMF...

Homework Statement A uniform rectangular coil of total mass 270 g and dimensions 1m x 5m is oriented perpendicular to a uniform 4.00-T magnetic field (the figure ). A current of 2.90 A is suddenly started in the coil. Homework Equations angular acceleration = torgue / moment of inertia...

Homework Statement A rectangular loop with length of l = 0.30 m and width w = 0.12 m and a mass of 25-grams falls (from rest) a distance of .28 m before entering a constant magnetic field that points out of the page. The internal resistance of the wire is 5.5 \Omega. (i) What is the speed of...

Homework Statement A coil is wrapped with 247 turns of wire on the perimeter of a square frame of sides 27.3 cm. Each turn has the same area, equal to that of the frame, and the total resistance of the coil is 2.53. A uniform magnetic field is turnedon perpendicular to the plane of the coil...

Homework Statement For a metal coil, if a magnetic field is being applied parallel to each circular loop, why is there torque being exerted on the coil? Homework Equations torque=(magnetic field)(area)(current) The Attempt at a Solution When I cross the current with the...

Homework Statement A circular coil having 20 turns and a radius of R = 12.8 cm carries a current of 2.70 A. It is placed in a uniform magnetic field of 60.0 mT. The initial angle between the magnetic moment of the coil μ and the magnetic field B is 26.0o. 1)Calculate the magnetic dipole...

ok, i recently acquired a 25mm spark gap induction coil. the input voltage is 6v dc. how can i know what the output voltage is? also, i want to use this as a substitue in place of a nst to power a 6'' tesla coil. will it work? i mean the basic idea is ot the a high voltage input and the...

Homework Statement You move a bar magnet through a coil at a constant speed. Graph the flux through the loop as a function of time. Graph the induced current in the loop as a function of time. Homework Equations The Attempt at a Solution Graph of flux vs time: I'm thinking is...

Homework Statement The primary coil of an ideal transformer is connected to a 120-V source and draws 1.0 A. The secondary coil has 600 turns and supplies an output current of 5.0 A to run an electrical device. A) What is the voltage across the secondary coil? B) How many turns are in the...

P type semiconductor coil... The magnetic field orientation in a P type semiconductor wire, in which a DC current is flowing will be caused by the direction of movement of the electrons or the positive holes?

Hello all, I'm currently working on a project and I have a question in regards to creating an efficient induction coil for our circuit. Without going into the specific details of the circuit(We aren't given the details anyways, just the circuit itself), it basically imitates a transformer...

Homework Statement If the rotation rate of a generator coil is doubled, what happens to the peak emf? Homework Equations The Attempt at a Solution I think it stays the same. Am i right?

A bar magnet is dropped from rest through the centre of a coil of wire which is connected to a resistor and datalogger. The resistor and datalogger are to the left in the diagram, and the coil on the right side. Add an arrow to the wire to show the direction of the induced current as the...

I got this formula for the magnetic field of a square-shaped coil: B = m0*2*sqrt(2)*I*N/(a*pi), where m0 is the permeability, and a is the side of the square... I can't really get why it is so, and my best tries resulted in approximation of the 'diameter' of the coil, for example by taking the...

I have seen the potential coil go across two phases to measure voltage. But there is no neutral attached to the potential coil. If the two lines were 120v ea. the potential coil will have 240v of potential going across it. How is it that this coil can measure the voltage in both...

Homework Statement A 10/1 stepdown tranformer has a full load secondary current of 50A and is rated 30kVA. The copper loss at full load is 280W. The primary winding has a resistance of 0.25ohms. The core losses are 120W. Find the resiatance of the secondary coil and the power loss in the...

Looked at Maxwell's eqns after quite some time,and was wondering, what happens if we apply an alternating flux to a superconducting coil? An emf should be produced, but there's actually no emf in a superconductor!

Homework Statement As shown in this picture: a 18 cm long solenoid with 1500 loops (N = 1500) and radius 2 cm is located at the center of wire frame (coil) that is 5(width) by 8(height) cm. There is a current inside of solenoid that is growing from 0 to 2.5 A in 7.5 seconds that rotates...

Dear Sirs, I was asked to design a Helmholtz coil. Being an electronic engineer, I can design electronic circuits but I have no idea about designing Helmholtz coils. Can you help me by suggesting a paper or article that describes a straightforward, step-by-step method for designing these...

Homework Statement http://img697.imageshack.us/img697/2317/img11l.jpg (a = 0.10 m and b = 0.16 m) i=3t^3 - 5t (i - ampéres t - seconds) Determine the voltage induced in the coil to the instant t = 3 sec. well as the current direction. Homework Equations Hall efect The...

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...

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...

Homework Statement A coil spring of mass m rests upright on a table. If you compress the spring by pressing down with your hand and then release it, can the spring actually leave the table? Explain, using the law of conservation of energy.

I'm building pairs of coils with standard core heights and diameters and linking each pair with a yoke. The magnets all run at 6V DC with windings of 24 AWG magnet wire in 6/8/10 layers. Is there a ratio of coil core mass to yoke mass for maximum efficiency? (shown below)