How to apply Faraday's Law of Induction

In summary, the conversation discusses how to measure ambient magnetic field strength using Faraday's Law of Induction. The speaker is having trouble understanding how to apply the law to their problem and is seeking a working example. They also mention using the Hall Effect for measuring DC currents and mention the importance of knowing the units in the equation n * dphi/dt. The other speaker suggests using a book called "The magnetic measurements handbook" and mentions building a fluxgate magnetometer.
  • #1
HyTronix
2
0
Greetings,

I have read the explanation on this forum here: https://www.physicsforums.com/showthread.php?t=441637 which discusses Faraday's Law of Induction, but I'm having a hard time understanding how to extrapolate that to my problem.

My goal:

Construct a circuit that measures ambient magnetic field strength, i.e., for finding wires, or determining if the ambient field strength is above a recommended (and likely arbitrary) background level of .5 Gauss.

I have a great deal of electronics experience, but, frankly, I'm terrible with math. Construction of the circuit is quite simple (I have a working spice model at any rate) but where Faraday's Law enters the picture is this:

-Assume the "probe" I've placed in this device is a 1mH inductor
-I'm expecting this probe to produce a voltage I can measure, likely in micro or millivolts

So, can anyone give me a working example that would help me understand this? For instance, if my 1mH inductor was placed into a field of .5G strength coming from a 60Hz power line, what voltage would be induced on the probe?

Thanks,

-John
 
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  • #2
Google for Hall Effect. That effect is essence for measuring ambient magnetic fields, Concept is quite simple. Although that is for DC currents, I think it should apply somehow to AC.
 
  • #3
aha magnetics is not well taught IMHO. n * dphi/dt is fine but what are the units?

i used ten turns on 14 inch diameter to give 0.1 square meter coil
so the voltage induced was direct indication of omega * (d phi/dt), flux in webers/m^2 which is 10,000 gauss.. at 60 hz w is 377 so next time i might make the coil 1/3.77 square meters.

i hope i have units right...

if your 1mh inductor is air core it might work but i wouldn't trust an iron core for fear it'll concentrate flux.

you need this book
http://books.google.com/books/about/The_magnetic_measurements_handbook.html?id=byy_GwAACAAJ

it's great. i built his fluxgate magnetometer.
 
  • #4
Thanks to both of you. I'll definitely grab a copy of that book.

-John
 

FAQ: How to apply Faraday's Law of Induction

How does Faraday's Law of Induction work?

Faraday's Law of Induction states that a changing magnetic field will induce an electromotive force (EMF) in a closed conducting loop. This EMF will cause a current to flow in the loop, which can then be used to power electrical devices. Essentially, the law describes the relationship between a changing magnetic field and the resulting electric current.

What is the equation for Faraday's Law of Induction?

The equation for Faraday's Law of Induction is:
EMF = -N * (ΔΦ/Δt)
where EMF is the electromotive force, N is the number of turns in the conducting loop, and ΔΦ/Δt is the rate of change of the magnetic flux through the loop. This equation quantifies the relationship between the induced EMF and the factors that affect it.

How is Faraday's Law of Induction applied in real life?

Faraday's Law of Induction has numerous applications in everyday life, such as in generators, transformers, and induction cooktops. It is also used in power plants to generate electricity and in electronic devices like microphones and speakers. Additionally, electromagnetic induction is the basis for wireless charging technology.

What factors affect the magnitude of the induced EMF?

The magnitude of the induced EMF is affected by several factors, including the strength of the magnetic field, the speed at which the field changes, and the number of turns in the conducting loop. Additionally, the size and shape of the loop, as well as the material it is made of, can also influence the induced EMF.

How can Faraday's Law of Induction be used to generate electricity?

Faraday's Law of Induction is the basis for electricity generation in power plants. A rotating turbine is used to spin a magnet inside a coil of wire, creating a changing magnetic field. This changing field induces an EMF in the coil, which then produces a current that can be used to power homes and businesses. This process is known as electromagnetic induction and is the principle behind most forms of electricity generation.

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