Toroid Definition and 67 Threads

In mathematics, a toroid is a surface of revolution with a hole in the middle, like a doughnut, forming a solid body. The axis of revolution passes through the hole and so does not intersect the surface. For example, when a rectangle is rotated around an axis parallel to one of its edges, then a hollow rectangle-section ring is produced. If the revolved figure is a circle, then the object is called a torus.
The term toroid is also used to describe a toroidal polyhedron. In this context a toroid need not be circular and may have any number of holes. A g-holed toroid can be seen as approximating the surface of a torus having a topological genus, g, of 1 or greater. The Euler characteristic χ of a g holed toroid is 2(1-g).

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  1. E

    Calculating Inductance of Toroid Core - Tips & Formula

    Hello, I need help with calculating inductance of a toroid core. I tried googling and came up with 3 results, but they don't really help. Links are: http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/indtor.html http://www.nessengr.com/techdata/toroid/toroid.html...
  2. S

    Toroid Air Gap: MMF, B-H Curve, Flux Density & More

    Homework Statement (I have done parts i) through v) correctly. It is the remaining two I'm stuck on. A toroid of rectangular cross-section has a height of 10mm, an inner diameter of 68mm and an outer diameter of 82mm. It is made of iron and is wound with 118 closely-spaced turns. When a...
  3. N

    Induction Experiment - Magnetic Field through a Toroid

    I want to build a simple induction apparatus like the one displayed at this web page: http://micro.magnet.fsu.edu/electromag/java/faraday/" My first attempt didn't work, and I'm trying to troubleshoot it. I am wondering how much magnetic field degradation there is around the toroid. As the...
  4. N

    Ampere's Law: Find |H| at (6cm, 9cm, 0) in Toroid

    1. Homework Statement A toroid of a circular cross section whose center is at the origin and the axis the same as the z-axis has 1000 turns with po=10cm, a=1cm. If the toroid carries a 100mA current, find |H| at (6cm, 9cm, 0). 2. Homework Equations How do I calculate |H| at...
  5. M

    Why is the b field inside a thick toroid largest along inner edge

    Why is the b field inside a thick toroid largest along inner edge and smallest along outer edge?
  6. S

    Magnetic toroid - coupling to a power line

    I need to obtain a toroid for inductive coupling to medium voltage power lines. The frequencies to be coupled are between 10 kHz and 900 kHz. Bear in mind that at power frequency (50 Hz), the current will be high (up to 100 Amps). Anyone have any idea on a magnetic material that can achieve...
  7. H

    How Strong is the Magnetic Field Inside a Toroid?

    You are going to wrap a toroid with 273 m of copper wire that can carry a current of I = 1.7 A. The toroid has radius R = 16 cm and cross sectional diameter D = 1.2 cm. How large a magnetic field (T) can you make at the average toroidal radius? I have been using the formula B =...
  8. S

    Calculating Magnetic Field of a Toroid Using Ampere's Law

    Use ampere's law to determine the magnetic field (a) inside and (b) outside a toroid, which is like a solenoid bent into the shape of a circle. Here is my work.. IS MY WORK CORRECT? a.) B(2PIr)=MoIenc and I found that B=MoNI/2pir b.) the magnetic field is 0 outside the loop
  9. J

    Magnetic field in the center of the toroid

    Can't this be calculated from B = mu*N*I/2*pi*r? Book explanation says that this can't be done because there is "no path through the center along which the field is constant" So I guess I must use the Biot-Savart Law. How should I go about doing that?
  10. J

    Direction of Magnetic Field in a Toroid with Clockwise Current Loop?

    Inside the toroid, in which direction does the magnetic field point, if the current is going clockwise around the loop? So I tried to consider the fields due to two points on opposite sides of the toroid. Then I got stuck becuase I don't know what direction their fields added up. What do I do?
  11. S

    How to Calculate Magnetic Field in a Toroid Using Ampere's Law?

    Homework Statement Use Ampere’s law to calculate the magnetic field inside of a toroid with 850 turns. The inner radius of the rectangular coils is 3.00 cm, the outer radius is 7.00 cm. Homework Equations ampere's law: path integral(B*ds) over a closed path is equal to the enclosed...
  12. B

    Magnetized Toroid Problem 6.10 - Griffiths EM

    Hello, I needed some help with a problem from the Griffiths Book on EM. It's problem number 6.10 if anyone has the book. Here is the problem and I have attached a crude drawing using MSPaint. An iron rod of length L and square cross section (side a), is given a uniform longitudinal...
  13. Reshma

    Calculating Energy Stored in a Toroidal Coil

    Calculate the energy stored in a toroidal coil. The magnetic field in a toroid is give by: B = \frac{\mu_0 n I}{2\pi r} Energy stored is given by: W = {1\over 2\mu_0}\int B^2 d\tau W = {1\over 2\mu_0} \frac{\mu_0^2 n^2 I^2}{4\pi^2}\int {1\over r^2}d\tau How do I determine the volume element...
  14. S

    Toroid shape Electro-Mag question

    I have a difficult probelm to solve: There is a dougnut shape (toroidal coil) with N turns of wire wrapped around it. Current I flows in the wire. THe cross section of the 'doughnut' is square with height h. I am meant to use ampere's law to prove that the magnetic field at a radius r from...
  15. M

    What is the magnitude of the magnetic field inside the toroid

    A toroid having a square cross section, 5.00 cm on a side, and an inner radius of 16.0 cm has 600 turns and carries a current of 0.700 A. (It is made up of a square solenoid bent into a doughnut shape.) (a) What is the magnitude of the magnetic field inside the toroid at the inner radius...
  16. E

    Hydrogen-Boron Plasma Toroid Fusion

    Dear Folks: I have posted this Question all over the web, physics forums, science magazines, academics in plasma physics and condensed matter, I have received little response. Can you be of assistance? I thought this might interest you. I have been researching Hydrogen-boron...
  17. E

    Hydrogen-boron High Density Plasma Toroid Fusion

    Dear Sirs: I have posted this Question all over the web, physics forums, science magazines, academics in plasma physics and condensed matter, I have received little response. Can you be of assistance? I thought this might interest you. I have been researching Hydrogen-boron Fusion...
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