Solenoid Definition and 752 Threads

  1. A

    My made solenoid doesnt induce magnetic field. What did I miss?

    Hey, I have a school project and I need a solenoid to induce a magnetic field. http://www.yourpicbox.com/images/orhBIhKZq6426.jpg I made a solenoid by winding a wire (I'm not sure what to call this wire. It's thin and brown.) to a pen case. I made 3 layers, 100-200 turns each. When I tested it...
  2. P

    Self Resonant Frequency in a Solenoid

    Hey guys, As a hobby I've decided to pick up EE and I've been reading quite a bit and I'm interested in building some basic circuits and determining the SRF in some coils that I've wound. I have found that you can calculate SRF using this formula: ......(1/5) ...29.85 x (H/D) F =...
  3. X

    Energy Stored in Magnetic Field of Solenoid

    Homework Statement The magnetic field inside an air-filled solenoid 39.9cm long and 2.00cm in diameter is 0.800T. Approximately how much energy is stored in this field? Homework Equations U=(1/2)LI^2 => U = (1/2)(B^2)(area*length)/(u) The Attempt at a Solution I discovered how to...
  4. eberg

    Help me read this solenoid diagram please

    Can someone help me understand what this solenoid is doing? It's somehow integrated into a switched shutoff system. I'm trying to figure out if I can jump two wires or ultimately add an on-off switch in line somewhere between the switch and this solenoid. Thanks for any help. click to...
  5. J

    What Equation Calculates Magnetic Field Strength in a Solenoid?

    Homework Statement During a lab we used a 570turn solenoid powered by a current of 5amp. For the last part of the experiment we were to take several measurements of the field strength across the cross-section of the solenoid. So we moved the field sensor around inside the solenoid and made...
  6. I

    Magnetic Flux through a solenoid

    Homework Statement The magnetic field inside a cylindrical solenoid of area 4 cm^2 is 0.15 T along the axis of the solenoid. What is the magnetic flux through a disk of radius 3 cm placed perpendicular to the solenoid axis? Homework Equations \phi = \zeta B * dA The Attempt at a...
  7. B

    GHz AC Frequency - Max "Practical" Generation: Solenoid Q&A for Experts

    GHz ac frequency- Maximum "Practical" generation - Solenoid question for the experts. It's me again. Big ideas, big questions. (A quick special thanks to everyone who has ever taken a moment to answer my questions: (Bob S, bipolar, Phrak, f95toli, jambaugh, waht, Pumblechook, ZapperZ...
  8. A

    Magnetic Flux Density at different points about a solenoid

    Homework Statement For my physics investigation I am required to first find the theoretical magnetic flux denisty at different points about a solenoid. The points are outside the solenoid: along the axis but past the ends and; perpendicular to the centre of the solenoid but outside. So far...
  9. J

    Solenoid Field Error: Why Highest at Center?

    Homework Statement I ran an experiment to find the magnetic field inside a solenoid at different points using a magnetic sensor, attached to a computer and interface. Starting at the center of the solenoid and moving outwards to the end, I collected points at 1cm increments (starting at the...
  10. D

    Field outside a solenoid on its axis

    Homework Statement A tightly wound solenoid of length L and radius a that has n turns of wire per unit length carries a current I. Calculate the the magnitude of the magnetic field at a point P on the axis of the solenoid, outside it and a distance y from one end, as shown in the figure...
  11. W

    The current and magnetic field of an ideal solenoid.

    This is not a homework question, it's just to help my conceptual understanding of two quick things: Suppose you have an ideal solenoid placed horizontally in front of you. The current is traveling (spiralling) from your left to your right. What direction is the magnetic field inside the...
  12. N

    Finding induced emf of solenoid

    Homework Statement A 800-turn solenoid, 18 cm long, has a diameter of 2.9 cm. A 15-turn coil is wound tightly around the center of the solenoid. If the current in the solenoid increases uniformly from 0 to 3.1 A in 0.28 s, what will be the induced emf in the short coil during this time...
  13. K

    The rate of current through a solenoid - clarification needed.

    Homework Statement http://www.aijaa.com/img/b/00106/3735947.jpg Homework Equations \epsilon =- \frac {d \Phi}{dt}=- \frac {d BA}{dt}= \oint \vec{E} \cdot d \vec{l} B= \mu _0nIA , where n is solenoid's turns per meter. The Attempt at a Solution I was able to solve this through trial and...
  14. S

    Trying to achieve at least 1 Tesla for a solenoid

    I am trying to produce a magnetic field with a flux density of 1 Tesla through a solenoid with an iron core and I am having trouble crunching the numbers. I may also be doing the wrong computations. I am not too sure of the permeability of the iron core, I've seen different values, one being the...
  15. Y

    Current induced in loop - treat like a solenoid?

    Homework Statement A long straight wire lies below to a circuluar loop of wire. The straight wire is carrying a constant 10A current to the right. What is the magnitude and direction of the current in the circular loop, if its diameter is 1 m and its center is 0.75m away from the wire...
  16. H

    Mutual Inductance of solenoid and coil

    Find the mutual inductance (H) of the solenoid and coil shown below. The solenoid has 5263 turns per meter and an area 112 cm^2, and the coil has 230 turns and an area 19 cm^2. I know that mutual inductance = (N1 Φ1)/ I2 but I have no idea where to begin since they don't provide the...
  17. G

    Magnetic Field of an Infinite Solenoid

    The question is basically asking you to find an expression for the magnetic field of an infinite soleniod, through the center of the solenoid(lengthways), and around the coils of the soleniod. I know, with help from te textbook, that the magnetic field of a loop is 2(pi)b^2I/cr^3. Where b is...
  18. L

    Can Symmetry Arguments Simplify Ampere's Law for Solenoids?

    I need to use Ampere's Law and Gauss' Law to show that inside a solenoid B_r=0,B_\theta=0,B_z=0 i tried using cylindrical polars on ampere's law but the expression just got really long and i couldn't see any way out of it.
  19. J

    How Do You Choose Wire Type and Calculate Potential Difference for a Solenoid?

    Homework Statement You want to construct a solenoid 20cm long that has an interior magnetic field Strength B (Bc) of about 1.5MN/C. The coil has to be wound as a single layer of wire around a form whose diameter is 3.0 cm. You have two spools of wire handy. #18 wire has a diameter of about...
  20. R

    How Does Material Permeability Affect Force in a Solenoid's Magnetic Field?

    Force Inside a Solenoind ? Hello I'm working on a personal project which involves a solenoid. I'm trying derive an equation for the Force(N) that an object would experience due to the flux density inside the coil. The flux density can be calculated relatively easily by the fallowing...
  21. T

    Magnetism - Quick solenoid question

    Homework Statement A 200-turn solenoid having a length of 25cm and a diameter of 10cm carries a current of 0.29A. Calculate the magnitude of the magnetic field B inside the solenoid. Homework Equations B = \mu0ni The Attempt at a Solution Well, I plugged the numbers into the...
  22. A

    Simple Solenoid Problem Solution Using Ampere's Law

    Homework Statement the question can be found here: http://www.mailfreeonline.com/uploader/CED0D65C.jpg Homework Equations ampere's law The Attempt at a Solution a. (is B the magnetic field?) B = uI/L; u = 4pi x 10^-7, I = 1, L = 2pi x 0.1 so B = 2 x 10^-6 ^ can anyone...
  23. J

    Questions about movement of a permanent magnet inside of solenoid.

    I have been doing some experimenting with a relatively short cylindrical permanent magnet and a solenoid with DC current applied. I would like an explanation as to why these two things happen. The OD of the cylindrical magnet is just a little bit smaller then the ID of the solenoid. Placing...
  24. B

    What Is the Magnetic Field Inside a Long Solenoid?

    hi, My homework is : Qualitative description of field due to long solenoid. I think I post in wrong box, that box is about the calculus problem, right? But I'm a new member and I don't know where to post my question. So if I'm wrong, I'm sorry, please answer me once and tell me the right box...
  25. I

    Non uniformly wound solenoid (no Mag. field?)

    I made two solenoids using the same amount of wire (1000ft of 24 AWG) around 2 identical bobbins. One of them I painstakingly wound the wire uniformly and tightly. This solenoid is strong enough to pull a steel rod into the middle of the core. The other I haphazardly wound as fast and...
  26. E

    Designing a Solenoid: Equations and Force Calculations

    I have to design a solenoid. It should be wound on some soft metal of certain permeability. It should have hollow inner dia that will be used to operate a gas valve. The problem is which equations should I use to design the solenoid. I also have to calculate the force that will be required for...
  27. E

    How can I calculate the inductance of a solenoid for my device?

    I have to make a solenoid to operate some device. Can anybody let me know what formula to use to calculate number of turns for a solenoid wound on some metal. I also want to calculate the force. Does this formula works B = uourNI/L & F = ILB
  28. B

    Flux Linkage with a coil in a solenoid

    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...
  29. T

    Compass in a solenoid, oscillating

    Homework Statement A compass, consisting of a small bar magnet resting on a frictionless pivot through its centre, is placed in the middle of a long solenoid, which in turn is aligned with its axis pointing North-South. With a current of 1 Amp passing through the solenoid, a small...
  30. S

    Designing a battery operated solenoid

    I want to develop a solenoid for push application. the required push is around 5kg by electromagnet. We can use a combination of permenant magnet and electromagnet to optimize the design with respect to area and power consumption. For eg. the solenoid can push a permenant magnet also...
  31. C

    Magnetic field in an AC Solenoid Coil

    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...
  32. S

    Calculating Electrical Parameters of Solenoid Coil for Spring Force

    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 .
  33. P

    How Does a Silicon Steel Core Affect a Solenoid's Magnetic Field?

    1. Homework Statement A long solenoid with 70.0 turns of wire per centimeter carries a current of 0.100 A. The wire that makes up the solenoid is wrapped around a solid core of silicon steel (Km=5200). (The wire of the solenoid is jacketed with an insulator so that none of the current flows...
  34. P

    Solenoid with a magnetic core problem

    Homework Statement A long solenoid with 70.0 turns of wire per centimeter carries a current of 0.100 A. The wire that makes up the solenoid is wrapped around a solid core of silicon steel (Km=5200). (The wire of the solenoid is jacketed with an insulator so that none of the current flows...
  35. M

    The Magnetic Flux through a Solenoid

    Homework Statement Find the magnetic flux through a solenoid of length 31.2 cm, radius 1.5 cm, and 610 turns that carries a current of 3.8 A. (in Wb) Homework Equations B_solenoid=u0*N*I/L Flux= B *A The Attempt at a Solution So to find the magnetic field, I plugged the...
  36. R

    Finding turns per meter in a solenoid

    Homework Statement The magnetic field produced by the solenoid in a magnetic resonance imaging (MRI) system designed for measurements on whole human bodies has a field strength of 4.0 T, and the current in the solenoid is 300 A. What is the number of turns per meter of length of the...
  37. J

    Induced current of a coil surrounding a solenoid

    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...
  38. G

    What is the Motional EMF in a Solenoid with a Square Loop Inside?

    Homework Statement A square, single-turn wire loop 1.00 cm on a side is placed inside a solenoid that has a circular cross section of radius 3.00 cm, as shown in the figure below. The solenoid is 16.0 cm long and wound with 95 turns of wire. (a) If the current in the solenoid is 3.00 A...
  39. A

    Primary solenoid with secondary coil effect? if any?

    primary solenoid with secondary coil...effect?? if any?? A primary solenoid of 1200 evenly spaced turns is wound on a cylindrical former 800mm long and 30mm in diameter. A secondary coil of 10 000 turns is wound around the central portion of the solenoid. A steady current of 2A is flowing in...
  40. J

    Magnetic flux through smaller coil within 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...
  41. A

    Magnetic flux through loop inside of solenoid

    Homework Statement A solenoid has 1800 turns of wire and is 125 cm long and 10.0 cm in diameter; see Figure P.14 (attached). A circular wire loop of diameter 5.0 cm lies along the axis of the solenoid near the middle of its length as shown. (a) If the current in the solenoid initially is...
  42. A

    Elec & mag, current wire in solenoid

    Homework Statement I took pictures of the problem with my camera, along with my solution. I couldn't get the picture to show on here, so I uploaded them to my myspace. please look at the pics in the links! the problem...
  43. N

    How Do You Calculate the Magnetic Field and Energy in a Solenoid?

    Homework Statement Consider a solenoid of length L, transverse area A, total number of loops N Compute the magnetic field B inside the solenoid, assuming that it is uniform and vanishes outside the solenoid, neglect any boundary effects. Working under the same assumptions, calculate...
  44. K

    Is There a More Accurate Equation for the Magnetic Moment of a Solenoid?

    Does anyone have an equation that describes the magnetic moment of a solenoid that does not actually use number of turns as an input? I'm trying to validate a solenoid I have made with something like 11000 turns, but I'm not sure how accurate my number of turns in, so I need a second input...
  45. B

    What Path Does a Charge Take in an AC Solenoid?

    Hi, I was wondering about the path a charge placed in a solenoid that was flown through by alternating current would take. Would it move on a circularly? Thanks!
  46. C

    Solenoid flux-emf-current problem

    Homework Statement A solenoid inductor has an emf of 0.20 V when the current through it changes at the rate 10.0 A/s. A steady current of 0.10 A produces a flux of 5.0 microWb per turn. The number of loops in the solenoid is the value which needs to be found. Homework Equations...
  47. U

    How Can Current Influence Magnetic Field Strength in a Solenoid?

    Hey guys, I'm really having problems with this. Normally I get pretty good grades but this just has me completely stuck. It's hard because I have to design something, yet it doesn't seem like there's a lot of easily understanable information out there to draw from. Any help would be greatly...
  48. J

    Why Does Steady State Current in a Solenoid Exceed Initial Pull-in Current?

    Why is the steady state current through a solenoid greater than than the current when the plunger is first fully pulled in? I would expect it to be identical to the low peak in the current profile when the plunger hits the stop when fully engaged. Thank you, Jorge
  49. K

    Solenoid length of wire problem

    Hey so I have been trying this problem and just cannot get it. thanks for the help. To construct a solenoid, you wrap insulated wire uniformly around a plastic tube 12cm in diameter and 55cm in length. You would like a 2.0A current to produce 2.5kG magnetic field inside your solenoid. What...
  50. S

    B-field of ideal cylindrical solenoid, using Biot-Savart.

    Homework Statement Consider an ideal cylindrical solenoid of length L and radius a=L/2 on which a thin wire has been wrapped a total of N turns. A steady current I flows through the wire. Assume the wires are wound so tightly that the solenoid can be thought of as a collection of N parallel...
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