What is Solenoid: Definition and 743 Discussions

A solenoid (, from the Greek σωληνοειδής sōlēnoeidḗs, "pipe-shaped") is a type of electromagnet, the purpose of which is to generate a controlled magnetic field through a coil wound into a tightly packed helix. The coil can be arranged to produce a uniform magnetic field in a volume of space when an electric current is passed through it. The term solenoid was coined in 1823 by André-Marie Ampère to designate a helical coil.In the study of electromagnetism, a solenoid is a coil whose length is substantially greater than its diameter. The helical coil of a solenoid does not necessarily need to revolve around a straight-line axis; for example, William Sturgeon's electromagnet of 1824 consisted of a solenoid bent into a horseshoe shape.
In engineering, the term may also refer to a variety of transducer devices that convert energy into linear motion. In simple terms, a solenoid converts electrical energy into mechanical work. The term is also often used to refer to a solenoid valve, an integrated device containing an electromechanical solenoid which actuates either a pneumatic or hydraulic valve, or a solenoid switch, which is a specific type of relay that internally uses an electromechanical solenoid to operate an electrical switch; for example, an automobile starter solenoid or linear solenoid. Solenoid bolts, a type of electromechanical locking mechanism, also exist. In electromagnetic technology, a solenoid is an actuator assembly with a sliding ferromagnetic plunger inside the coil. Without power, the plunger extends for part of its length outside the coil; applying power pulls the plunger into the coil. Electromagnets with fixed cores are not considered solenoids.
The term solenoid also refers to any device that converts electrical energy to mechanical energy using a solenoid. The device creates a magnetic field from electric current, and uses the magnetic field to create linear motion.

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  1. A

    Find Magnetic Field of an Elliptical Solenoid | Biot-Savart Law

    Homework Statement I have to find an expression for the magnetic field of an elliptical solenoid. This is an actual solenoid sitting on the desk next to me, but even an infinite/very long solenoid approximation would be a wonderful start. Homework Equations Biot-Savart law The Attempt at a...
  2. N

    Regarding Solenoid and Magnets

    Hello, I was doing some questions and I thought I was understanding solenoids and magnets in incorrect way.. The question was, what would you feel if you bring a magnet close to a solenoid. I've wrote 2 possibilities, first is that they will repel and the second is that the solenoid would...
  3. S

    Magnetic Field inside a Solenoid (Please explain this answer to me)

    Homework Statement Q5. A solenoid is 3.0 cm long and has a radius of 0.50 cm. It is wrapped with 500 turns of wire carrying a current of 2.0 A. T Homework Equations Magnetic field of an ideal solenoid = permeability constant (1.257E-6) * current * number of turns The Attempt at a...
  4. M

    Calculate the solenoid dimension

    Hi to all, I have a problem to share with you guys. How can I calculate the thickness of my solenoid if I have these values; Solenoid long : 20cm magnetic field, B : 5Tesla Current, I : 20A Thanks a lot for your help. I appreciate that
  5. A

    Do most solenoid valves work for high acceleration loads?

    hey guys, i'm currently designing a fuel system for a ramjet to be tested onbaord a sounding rocket but it's going to pull around 100g's of acceleration. i can't get a hold of the manufacturer (still waiting for an email) and the supplier here in aus hasn't got a clue if it will survive the...
  6. S

    How Does Changing Current in an Outer Loop Induce Current in an Inner Loop?

    Homework Statement A small 2.0-mm-diameter circular loop with R = 0.020 Ohms is at the center of a large 100-mm-diameter circular loop. Both loops lie in the same plane. The current in the outer loop changes from +1.0 A to -1.0 A in 0.10 s. What is the induced current in the inner loop...
  7. Nabeshin

    Magnetic field produced by a solenoid

    Ok, so anyone who has studied magnetism knows that the magnetic field due to a solenoid is given by the equation B=\mu_oNI Where N is the number of turns in a given length. Well, in thinking about these, I tend not to make measurements and would rather like to predict the magnetic field of the...
  8. H

    Testing the Magnetism of a Solenoid & Galvanometer

    suppose you have a solenoid with hollow core connected to a galvanometer. On one side you have a S-N magnet (ie. the N pole is nearer to the solenoid). On the other side you have a N-S magnet( ie. S pole is nearer to solenoid). ie. [S - N] [Solenoid] [N - S] Both magnets are...
  9. S

    Find I(coil): Solenoid & Coil Setup

    Homework Statement A 44.0 -turn, 3.90-cm-diameter coil with R(resistance) = 0.510 surrounds a 2.40-cm-diameter solenoid. The solenoid is 16.0 long and has 240 turns. The 60 Hz current through the solenoid is I(solenoid)= 0.530Asin2\pift. Homework Equations Find the value of I(coil)...
  10. G

    Current in wire loop inside a solenoid

    Homework Statement A 2.1m -long solenoid is 13.0cm in diameter and consists of 2200 turns of wire. The current in the solenoid is increasing at the rate of 1.0 kA/s . The Attempt at a Solution Any help to point me in the right direction would be great. I'm thinking that i need to...
  11. H

    Electric-field strength inside a solenoid

    guys, here's my question: A long solenoid has circular cross section of radius R. The solenoid current is increasing, and as a result so is the magnetic field in the solenoid. The field strength is given by B = bt, where b is a constant...
  12. F

    Magnetic field of uniform strength at all points inside a solenoid?

    simple question: is the magnetic field of uniform strength at all points inside a solenoid?
  13. R

    Quick question about the flux density through a solenoid.

    Homework Statement the flux density through a solenoid is given by B=\mu_o n I Where n is the number of turns per unit length. The number of field lines per unit area is proportional to B. I am assuming that at or near the centre of the solenoid the number of field lines per unit area...
  14. T

    Magnetic field with solenoid, have work;

    Homework Statement A solenoid 10.0 cm in diameter and 77.2 cm long is made from copper wire of diameter 0.100 cm, with very thin insulation. The wire is wound onto a cardboard tube in a single layer, with adjacent turns touching each other. What power must be delivered to the solenoid if it is...
  15. T

    Analyzing Angular Momentum of Solenoid & Charge

    Homework Statement Given a long thin solenoid with a point charge of e. Initial conditions, e is at rest, the solenoid is on, i.e., there is current running through it, and the magnetic field outside is essientally 0 due to the length of the solenoid. Final conditions: the solenoid is...
  16. A

    Magnetic field outside a solenoid in 3D in terms of position

    Magnetic field outside a solenoid in 3D(off axis) Hey all, I am modeling an inductive proximity sensor and require the formula for the magnetic field just outside a solenoid off axis. In terms of a particle's position.i.e.(x,y,z). I have searched a lot of places. But most of the results show...
  17. P

    Solenoid Design: Achieving Optimal Ball Movement at High Velocity

    I know this isn't a homework related question but I felt these were simple enough questions where as I didnt need to flood the other forums. My situation is as such...I need to create a solenoid that can push a metal slug hard enough to move a very small ball. I know that solenoids are...
  18. P

    Solenoid produces a magnetic field help

    1. A solenoid is 0.20 m long and consists of 100 turns of wire. At its center, the solenoid produces a magnetic field with a strength of 1.5 mT. Find the current in the coil. 2. L be the length of the solenoid = 0.2m N be the number of turns = 100 B be the magnetic field = 1.5 mT...
  19. A

    Potential difference across a solenoid

    Hi, I have just started studying EM induction and I got stuck with the derivation of potential difference across a solenoid when the current in it is changing. My textbook (Physics for Scientists and Engineers by Tipler) derives it in very mathematical way just by saying that because the...
  20. A

    Induced electric field outside a solenoid

    Hi there. On my electromagnetism test there was the following question: A long solenoid with radius R has N turns per unit length and carries a current I = I_0*cos(ωt) Find the electric field inside and outside the solenoid. I got the following solutions: \vec{E} = \frac{\mu}{2} N...
  21. C

    Find Field and Direction in Coaxial Coils

    Homework Statement Find the field and direction inside a pair of coaxial coils. The inner coil carries 3.0A, has 500 loops and is 10cm long. The outer coil carries 10A, has 5000 loops and is 10cm long. Find the field at the center Thats the questions, now I don't have trouble working out the...
  22. R

    Release Type Solenoid Feasibility

    Hi All, I have a project and was hoping for some help here. I need to build a type of solenoid that will move a 3/4 inch diameter rod vertically about four inches and hold it there for a minute plus. This will have to be powered by a battery so energy use is a concern. I have an idea on how...
  23. T

    Induced EMF: Solenoid in Square Loop

    Homework Statement The solenoid has N turns of wire around a cylinder. The radius of the cylinder is "a" and length is "b." THe current of the solenoid varies as I(t)= I_{0}(1 - e^-\alphat) . I_{0} and \alpha are positive constants. Around the solenoid is a square loop of wire with side...
  24. C

    What is the magnetic flux through the solenoid

    [b]1. Magnetic field inside a long solenoid with cross-sectional area A is given by B=(mu)nI where n is the number of turns per unit length and I is the current. Suppose that the current is given by I(t) = I(0)e^(a*t) where t is the time and a and I(0) are constants. What is the magnetic flux...
  25. H

    Solenoid Valve? Area Adjustment?

    Hi all. I am now looking for a valve whose opening can be quite accurately controlled. The size of the opening shall be quite small, around 3mm - 1cm? I am wondering if you know any valve that may suit my usage? Can the opening of a solenoid valve be adjusted using electric signal?
  26. J

    What is the Inductance per Unit Length of a Solenoid?

    Homework Statement A solenoid is wound with a single layer of copper wire of radius 0.38 cm. The solenoid is 4.5 cm in diameter and 3 m long. What is the inductance of the solenoid per unit length? Assume that adjacent wires touch each other and that insulation thickness is negligible. radius...
  27. S

    Need Help With Pressure Downstream of Solenoid.

    I have an air cannon, which launches a ping pong ball. The setup for this includes the reservoir, solenoid and barrel. I have to find a function for the range of the launcher. I am currently stuck at working out the downstream pressure for the solenoid. At the moment I have the mass flow rate...
  28. W

    Magnetic Field outside a solenoid

    I am a physicist, a young physicist. I can't find information that agrees on how to determine the magnetic field at a distance from a solenoid. We use a ferrite rod of 7.5" long wound with wire over 6.5" of it. The frequency it oscillates at is 73 kHz. If I know the current how can I...
  29. M

    MATLAB Finite Solenoid On-Axis Field in MATLAB

    Does anybody know how the quadv function works in matlab? I am trying to get a plot of the on axis field of a finite solenoid, so the formula (given I didn't make some stupid mistake deriving it, which is beside the point) should be: H(z) = \int_{-L/2}^{L/2} \mu_0 \frac{NI}{2L}...
  30. K

    Find the maximum induced emf in the large coil solenoid

    Homework Statement Given: u_0 = 1.25664e-6 A 2 m long large coil with a radius of 14.6 cm and 320 turns surrounds a 4.2 m long solenoid with a radius of 4.6 cm and 7700 turns. The current in the solenoid changes as I = I_0 sin (2pi*f*t) where I_0= 30 A and f=60 Hz.Inside solenoid has...
  31. I

    Jackson 5.2b - realistic solenoid

    Homework Statement There is a realistic circular solenoid of infinite length. Current I flows in it, and there are N turns per unit length. The problem asks to show that just outside the solenoid there exists a magnetic field identical in magnitude and direction as that of a single wire on the...
  32. R

    Solenoid Electromagnet with strong core, low residual magnetism

    Hello, this is my first post here. I'm building an electromagnet as part of a larger experiment in my lab. My magnet needs to move a magnetic thread made with a paramagnetic substance. This string just barely responds to strong magnetic fields (tested it with standard speaker magnets). The...
  33. S

    Emf of coil outside a solenoid

    Homework Statement A coil of 120 turns and radius of1.8 cm and resistance of 5.3 ohm is placed outside a solenoid. If the current in the solenoid is changed, what current appears in the coil while the solenoid is being changed? Homework Equations emf= -dflux/dt = A*dB/dt emf=iR...
  34. W

    Have you ever heard Electric Field of one turn Solenoid?

    Have you ever heard "Electric Field of one turn Solenoid? hi, guys: Have you ever heard "Electric Field of one turn Solenoid"? Here is a example from MIT. Click on the weblink: http://web.mit.edu/6.013_book/www/book.html Click on the Chapter 10 in the left part of the screen...
  35. W

    Electric Stress between wires of a solenoid

    hi, guys: I am reading some notes of Electromagnetism. It claims that for a helix solenoid with N turns of wire, the distance between the successive coil is \Delta a, the total vertical length of the solenoid is d. The artical claims that if we apply a voltage v to this solenoid...
  36. M

    What exactly is the solenoid shape? Is it just the coil?

    What exactly is the solenoid shape? Is it just the shape of the coil with the core inside or do they refer to the shape of the magnetic field surrounding the coil?? Is this the solenoid, just the coil? Or are they talking about the magnetic field that surrounds the coil?
  37. G

    Induced E by a solenoid with time-varying current

    Imagine a solenoid with n turns per length. Now, for an instant, in which everything looks static, the magnetic field inside the solenoid will be n \mu_0 I \mathbf e_z (choosing solenoid alinged with z-axis), and zero field outside. Now, what would happen if we change the current in time? To...
  38. S

    Troubleshooting Solenoid Control for Pneumatic Slides

    :uhh: hey guys, I'm new in the field and I'm running into this basic problem that's giving a headache. I got a pneumatic slide that's supposed to go up and down. It's controlled by a double sol, 2 position (I'm pretty sure that's the type of valve on the machine now). The valve power is tied to...
  39. Alpha Russ Omega

    Magnetic Field, copper wire, and solenoid problem.

    Hello: I am having trouble starting this problem. "20.0 m long copper wire, 2.30 mm in diameter including insulation, is tightly wrapped in a single layer with adjacent coils touching, to form a solenoid of diameter 2.50 cm. What is the field at the center when the current in the wire is 26.0...
  40. S

    Magnetic fields of infinite solenoid and infinite current carrying plane

    I am following the book 'Introduction to Electrodynamics' by Griffith. In that book,the magnetic field outside an infinite solenoid has been found as follows: First of all,it is proved that the magnetic field is along the axis. (I have no problems with that proof). Then,a rectangular loop is...
  41. V

    Compact Muon Solenoid experiment simulations

    Hallo everybody! Is there anybody dealing with CMS stuff? Let's share infos here, and let's discuss the stuff related to Compact Muon Solenoid experiment simulations. I am a student, and have to work on H-->2mu ee- (Higgs to muon+ muon- electron positron) Plz, leave here any related...
  42. S

    Current of a coil surrounding a solenoid

    A 40-turn, 4.0-cm-diameter coil with resistance R=.40 ohms surrounds a 3.0-cm-diameter solenoid. The solenoid is 20 cm long and has 200 turns. The 60 Hz current through the solenoid is I = I_0 * sin(2pi*f*t). What is I_0 if the maximum current in the coil is 0.20 A? Basically, there is a coil...
  43. A

    Choosing the Best Valve: Ball vs Solenoid for Reliable Flow Control

    Hi, I want to know the difference between an actuated ball valve and a solenoid valve. Which one is more reliable? I want to program the valve so that it allows flow for 10 seconds to one outlet and after that direct the flow to the second outlet. I know I'll probably need a 3-way valve...
  44. G

    An Air-Filled Toroidal Solenoid

    Homework Statement An air-filled toroidal solenoid has a mean radius of 14.5 cm and a cross-sectional area of 4.99 cm^2 (see the figure). The current flowing through it is 11.7 A, and it is desired that the energy stored within the solenoid be at least 0.388 J. What is the least number of...
  45. A

    Power supply for solenoid valve

    what's the difference between AC and DC power source for solenoid valve?and what is mainly the power consumed for? for mature products available, what should be taken into consideration for power design? thanks
  46. M

    Creating a Solenoid Gun: Overcoming Midway Stoppage

    hi Guys, i am creating a solenoid gun, but my problem is that when i put my magnetized needle in the solenoid , it just stops in the midway , is there any way that my needle pass through the solenoid without stoping ( with a good speed ) i really need your help
  47. N

    How to tell the magnetic flux a certian distance from a solenoid?

    How to tell the magnetic flux a certian distance from a solenoid?? This is about a coursework problem that I've been trying to figure out for the past few weeks. This is my context, for those wanting to know i'm trying to predict the high of the ring, in the jumping ring experiment. For...
  48. Amith2006

    Magnetic flux through a solenoid problem

    Homework Statement In one of the problems dealing with solenoid, they gave the value of flux through the cross-section of the solenoid(say 1.6x10^(-3)Weber). Do they mean that this is the flux through a single turn of the solenoid? I get the answer if i take it this way. Homework...
  49. I

    Reducing Solenoid Valve On-Time with 24V Supply

    Hello, I am trying to decrease the time it takes for a 24V solenoid valve to open. This can be accomplished by increasing the voltage on the coil, but I only have a 24V supply to work with, and cannot replace the coils with lower wattage versions. Is it possible to somehow boost the...
  50. S

    Solving an Ideal Solenoid: Calculating Magnetic Field, Self-Inductance, and RMS Current

    Homework Statement A wire of length \ell, radius r_1, and resistivity \rho is tightly wound in a single layer into the shape of a solenoid with circular cross section of radius r_2. Assume it is an ideal solenoid. A DC voltage V is placed across the ends of the solenoid. a. What is the...
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