Solenoid Definition and 752 Threads

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.

View More On Wikipedia.org
  1. F

    Induced emf as a magnet passes through a solenoid

    I'm doing a lab write-up for physics 2. The experiment is about the title, a bar magnet being dropped through a solenoid. I have to explain four graphs that plot the change in emf (y axis) vs. time (x) axis. There are incoming and outgoing peaks on these graphs. I have to tie these results...
  2. A

    Solenoid variable voltage/position problem

    I am attempting to build a device that pulls against a spring at variable tensions, based on how much electricity is passed to it. I have read that solenoids don't "like" being charged for long without going to a closed position. That they burn out. The specific problem is that the spring...
  3. S

    Magnetic Field Strength Calculation for a Solenoid with Given Parameters

    Homework Statement A 10 cm long solenoid with 241 turns and radius R = 3.00 cm has a current flowing through it of Io = 200 mA. What is the magnetic field strength inside the solenoid (in T)? The Attempt at a Solution So i know i have to use the formula B = (uo)(n)(Io) uo = a constant 1.257 x...
  4. ?

    EM attraction between a solenoid and interstellar hydrogen

    Okay I have a really odd question that might be difficult to answer. I have searched for an answer in several physics books and websites and don't think I have come across a specific answer for this question. Suppose I were to send a negative electromagnetic charge through a solenoid and want...
  5. R

    Constant Field Throughout Entire Solenoid Axis

    Along the center of a very long solenoid tube the field strength is constant. At the ends of the tube, however, the field decays and drops off. Is there a simple way (mathematical solution or simple trick) to make the field perfectly constant (or to a fraction of a percent tolerance)...
  6. W

    Exploring the Use of Solenoids in Railgun Technology: Pros and Cons Revealed

    I haven't seen any discussion or any mention what so ever of this before so excuse me if it's that's because it's a crazy idea. What would be the pros and cons of using solenoids as the rails and projectile of a railgun? Would the stronger magnetic field of the solenoids allow a stronger force...
  7. H

    Problem in determinig Poles of a Solenoid

    Hi Everyone, I have made a solenoid of 100 turns. When i bring a small permanent magnet near the solenoid, it attracts the North pole of permanent magnet while it should attract the South pole according to right hand thumb rule... now i got confused. Kindly help me. Regards, hsn
  8. H

    Calculating Initial Speed of 2.7g Ball Launched at 45° with 50V Solenoid Input

    Homework Statement A ball ( 2.7 g ) is launched at a 45 degree angle with a solenoid input of 50V. What is the initial speed of the ball? Homework Equations KE = 0.5mv^2 PE = mgh dy = vy(0)t + 0.5at^2 dx = vx(0)t The Attempt at a Solution Voltage is potential energy and I...
  9. K

    Electromagnetic Induction: Solenoid & Magnet

    I have just learned electromagnetic induction and it states that if you move a magnet through a solenoid, you would get an induced current. Say, if you have a copper solenoid, and if you want to move a magnet through it, there will be something (maybe, a force) that would prevent the magnet...
  10. ¡

    Magnetic Field Outside of Finite Solenoid Greater for Air-Core or Ferrite-Core?

    These are finite solenoids/inductors and I only care about the field outside of the solenoids. Assuming identical coils and the distance on axis from the coil and the current through the coil is the same, will an air-core or ferrite-core inductor/solenoid create a greater magnetic flux...
  11. E

    Inductance of Solenoid w/ Rod Inside: R, L, N, I, μ

    A solenoid has a radius R, length L, with N turns and carrying a current I. If a cylindrical rod with permeability μ and radius R/2 is inserted inside the solenoid, what is the inductance of solenoid?
  12. P

    Solenoid and toroid inductance puzzle

    Im working with building a reluctance motor and I've posed a problem to myself that i cannot answer without questioning some long accepted facts about the inductance of a solenoid. The simple solenoid and toroidal solenoid are two shapes that seem to have simple equations for calculating the...
  13. Q

    What is the magnetic field of a solenoid and how does it change along the axis?

    Homework Statement Consider a solenoid of length L and radius R, containing N closely spaced turns and carrying a steady current I. (a) In terms of these parameters, find the magnetic field at a point along the axis as a function of distance a from the end of the solenoid. (b) Show that as L...
  14. F

    What is the Magnetic Field of a Toroidal Solenoid?

    Homework Statement A toroidal solenoid has inner radius r1=15.0 cm and outer radius r2=18.0 cm. the solenoid has 250 turns and carries a current of 8.50 A. what is the magnitude of the magnetic field at the following distances from the center of the torus (a) 12.0 cm; (b) 16.0 cm; (c) 20.0...
  15. A

    Elctromagnetic induction by a solenoid moving with the speed of light?

    Elctromagnetic induction by a solenoid moving with the speed of light?? The moment the magnetic field is generated, it should take some time to reach some distance. It cannot reach infinity instantly, it should have some speed, and that speed cannot be more than that of light. So let’s say that...
  16. ElijahRockers

    Electric field at perpendicular distance R due to a Solenoid

    Homework Statement A solenoid as viewed from the left has a current carrying wire wrapping around it counter clockwise. The current travels from left to right. The current varies as: I=I_0sin(wt) According to Faraday's law, this will result in electric field. From symmetry, the electric...
  17. F

    How Many Turns Are Needed for a Solenoid with Given Parameters?

    Homework Statement It is desired to construct a solenoid that has a resistance of 9.94 Ω (at 20◦C) and produces a magnetic field at its center of 0.0224 T when it carries a current of 5.17 A. The solenoid is to be constructed from copper wire having a diameter of 0.517 mm. Find the number of...
  18. X

    Solenoid magnetic flux and emf

    Homework Statement A wire of resistance 11 ohms and length 2.3 m is bent into a circle and is concentric with a solenoid in which the magnetic flux changes from 8 T·m2 to 6 T·m2 in 0.2 seconds. a) What is the emf in the wire? b) What is the non-Coulomb electric field in the wire? c)...
  19. I

    Emf of a single loop wire around a solenoid

    Sorry, the title is wrong. Should be "magnetic flux" of a single loop wire around a solenoid. Homework Statement A solenoid 4 cm in diameter and 20 cm in length has 250 turns and carries a current of 15 A. It is surrounded by a loop of wire 10 cm in diameter. The loop is positioned...
  20. O

    On-axis field degradation of solenoid

    Homework Statement I have to calculate the induced current in a coil a known distance from a solenoid (the secondary coil is on the axis of the solenoid). As the magnetic flux from the solenoid weakens with distance, I have applied biort-savart law to determine the stength of the magnetic...
  21. B

    Solenoid Induction Homework: Bz & Flux Calculation

    Homework Statement A solenoid has length L = 20 cm, radius 6 cm, and N1 = 4500 turns; its axis coincides with the z-axis. A circular conducting loop containing N2 = 11 turns of radius a = 1 cm is centered inside the solenoid; the plane of the loop makes a 30° angle with respect to the z-axis...
  22. L

    Calculating Capacitance to Limit Voltage in Solenoid

    Homework Statement A solenoid with self-inductance L=2H and carrying a steady current of 1 A has the current source suddenly turned off. What is the minimum capacitance that should be connected across the terminals of the solenoid in order to prevent the potential difference generated by...
  23. T

    Is my solenoid's resistance too low?

    I've just calculated the resistance of a solenoid I'm making, but it seems far too low. 240 turns of 1.6mm wire, 30 turns per row, 8 rows deep. total length of wire (L) = 21.96m area of wire (A) = pi * (0.0008)^2 m^2 resistivity of copper (rho) = 1.6*10^-8 ohms m^-1 R = (rho * L) / A...
  24. S

    Force of a solenoid on a magnet?

    I'm trying to calculate the force between a solenoid and a magnet inside that solenoid. Would someone be able to explain how I would be able to calculate the force a solenoid of n number of turns and l length with a current I running through it would put on a magnet whose center is a distance d...
  25. F

    Calculate the energy associated with the magnetic field of a solenoid

    Homework Statement Calculate the energy associated with the magnetic field of a 191-turn solenoid in which a current of 1.37 A produces a magnetic flux of 3.52 10-4 T · m2 in each turn. mJ uo=4pie x10^-7 Homework Equations ub=B^2/2uo(the constant) U=1/2LI^2 The Attempt at a...
  26. U

    Magnitude of induced voltage in conductor within AC solenoid

    Please note, I'm not in school anymore -- just a basic physics question! Homework Statement A conductor is placed inside the coil of an induction heater. Imagine that the inductor coil has radius R, number of turns N, operating frequency f [Hz], drawing current I = I0 * sin(2*pi*f*t). The...
  27. A

    Formula for the magnetic field inside a solenoid

    A 29.8 mA current is carried by a uniformly wound air-core solenoid with 390 turns. the length of the coil is 13.1 cm, with a diameter of 20.8mm. The permeability of free space is 1.25664 X 10^(-6) N/A^2 compute the magnetic field inside the solenoid. answer in units of T Relevant...
  28. C

    EMI - Current in solenoid due to magnet

    Homework Statement The Attempt at a Solution Suppose that N pole of magnet is facing the solenoid considering view from magnet when the magnet moves close ... current is anticlockwise and increase from 0 to max till magnet reach starting of solenoid when it enters the solenoid ...
  29. F

    Long solenoid, calculating electric field.

    Homework Statement A long solenoid with 5.00x10^2 turns per meter and radius 2.00 cm carries an oscillating current I = 6.00 sin 90πt, where I is in amperes and t is in seconds. (a) What is the electric field induced at a radius r = 1.00 cm from the axis of the solenoid? (Use the following as...
  30. S

    Force on a conducting ring due to solenoid with AC current

    Homework Statement A long circular solenoid of radius a and N turns per unit length has its axis in the z direction. A small highly conducting ring, or area A, resistance zero but self inductance L, is place with its plane horizontal and its centre on the axis and near the top of the...
  31. M

    Magnetic field produced by coil and solenoid

    Can someone please tell me why the formula for B at the center of a coil and the formula for B inside a solenoid give widely different answers in this problem? From Serway and Vuille, College Physics: "A solenoid with 500 turns, 0.10 m long, carrying a current of 4.0 A and with a radius of...
  32. K

    Mutual Inductance of a conducting loop and a solenoid

    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...
  33. K

    What Is the Magnetic Field at the Center of a Solenoid?

    This is driving me insane. This is all I can think of to do, and my teacher said it was wrong. A solenoid of length 0.25m and radius 0.025m is comprised of 440 turns of wire. Determine the magnitude of the magnetic field at the center of the solenoid when it carries a current of 12 A...
  34. J

    Can a Loop of Wire Be a Solenoid?

    Can a loop of wire be considered a solenoid, which has been turned once? -Thanks.
  35. M

    Magnetic field due to a solenoid

    Homework Statement A 5-turn coil 1.0 cm in diameter is rotated at 10 rev/s about an axis perpendicular to a uniform magnetic field. A voltmeter connected to the coil through rotating contacts reads a peak value of 360 uV. What is the magnetic field strength? The Attempt at a Solution...
  36. Z

    Induced current due to a Solenoid

    Homework Statement Two metallic rings A and B, identical in shape and size but of different resistivities Pa and Pb are kept of the top of two identical vertical solenoids. When current I is switched on in both the solenoids in an identical manner, the rings A and B jump to heights ha and hb...
  37. B

    Calculate electromagnetic momentum given a solenoid and point charge

    Homework Statement A point charge q is a distance a > R from the axis of an infinite solenoid (radius R, n turns per unit length, current I). Find the linear momentum and the angular momentum in the fields. (Put q on the x axis, with the solenoid along z; treat the solenoid as a nonconductor...
  38. M

    Why Is B°dl Zero at Sections b and d Inside a Solenoid?

    Homework Statement Explain why the contribution of B°dl of the magnetic field at sections b and d of the enclosure length must be zero, even inside the solenoid. Homework Equations Ampere's Law: ∮ B dl= U_0 I_enclosed NThe Attempt at a Solution The right and left sides of the loop have a...
  39. T

    Solenoid in open circuit and with glavanometer attached

    1.A student performs an expierment on a soenoid. The solenoid is open circuit in the first instance, the studet then pushes a magnet into one end with a constant force. the second instance, the solenoid is connected to a galvanometer. Using the concept of energy conversion, relate and explain...
  40. A

    DC Linear Solenoid: Generating 60 Amp Current for Robotics Project

    I am using a DC push-type solenoid as the mechanism for shooting in my robotics project. I have to use 12V DC supply and have to shoot TT balls for distances upto 3-7 feet. The solenoid specifications suggest that it requires 60 amp current. How do i generate this?? Thanks in advance
  41. G

    How Can I Conduct a Solenoid Experiment Without Equipment?

    Hello, I am doing a solenoid experiment, where I will be examining e.m.f, flux density, Flux, Magnetic field strength, electric field strength, etc... but I have no apparatus or the equipment with me. I was wondering whether someone who has got the equipment could correct all the data for me...
  42. D

    Activation of a solenoid via induction

    First and foremost, I admit that this was not my strong point in physics. I am trying to construct a realistic model in excel or maple which could be used to predict induced voltage in a solenoid based on it's distance to a virtually infinite extremely high voltage, power source. The source...
  43. Y

    Help in TEM wave propagation for a solenoid or magnetic dipole.

    I am trying to figure out how the TEM wave looks like and how it propagate outward. Attached is a pdf of a drawing with only the solenoid and show the winding that the current is flowing in CCW and a reference. Also I draw a loop with one resistor and show the induced current and the polarity of...
  44. A

    Understanding Voltage Rating for Electro-Mechanical Solenoids in Robotics

    I m designing an electro-mechanical solenoid as the shooting mechanism in a robot. Its input is DC current. But, my guide asks me to mention its voltage rating. What is this and how to find it out?
  45. G

    Exploring the Electric Field in a Solenoid

    Can we find an electric field in a solenoid? Just a little confused
  46. G

    Where is magnetic field strongest in a solenoid?

    Where is magnetic field strongest in a solenoid?
  47. T

    What is the acceleration of a charge near a solenoid?

    Homework Statement Hi! Yesterday was the deadline of a monthly competition, and I couldn't solve one problem. Please take a look at it: http://www.komal.hu/verseny/feladat.cgi?a=honap&h=201011&t=fiz&l=en" It's the last problem, worth 6 points with the image of a solenoid Homework...
  48. L

    Efficiency & Leakage in non-circular solenoid cores

    Part of a new product we're designing needs a small iron-core D.C. electromagnet for an actuator. I designed the electromagnet's core to be circular: about 4.5mm in diameter with 200 Ampere-Turns in the coil. An axis-symmetric FEA showed the iron core to be near saturation, and producing a...
  49. R

    Torque on a loop within a solenoid?

    Homework Statement Question: A solenoid has of radius 100mm and turns density of 5 turns/mm has a current of 10 Amps flowing in it. There is a loop of radius 15mm and 25 turns within the solenoid. The loop is free to rotate about an axis which is normal to the axis of the solenoid...
  50. Z

    Magnetic Field at a point outside a solenoid

    Someone please explain me why is the magnetic field at a point outside a current carrying solenoid 0? I read many books but can't understand what they mean. I understood that the magnetic field at a point in between to adjacent coils is 0 as the 2 fields oppose each other. Why and how is it 0...
Back
Top