Coils and magnetic fields

So, HHC oils will driven at 1 Hz ( s> =A0 =A0This is magnetic flux measurements other wise know as a single

So, magnetic flux will be measured > =A0 =A0 Now I suppose you could apply a DC current to your coils that wou=

ld

Did not understand it ? I want to measure the field created by HHC coils.

jess

You can do that but it won't help. In the end the efficiency will boil down to coil diameter and number of turns. If you reduce that -> less signal. No matter what the contruction of the coil. Since you mentioned weight a circuit board might not be so great because that adds the weight of the FR4 which contains a resin that weighs something.

If you just want to measure the field, how about a very small coil with few turns and a little amp right at that coil?

It does not matter if you pass a secondary loop of wire through a stationary field once/sec or, you place that loop of wire in a field that is not stationary.. The results are the same. what does matter however, is where that detection loop (secondary) is which determines the Flux (WB) or that area.

The fact that you are not using 1 Hz, which is obvious, means you must take your 100 kHz or what ever you're using and scale it.

Jamie

Seems to me you would want this loop untuned, i.e. no parallel capacitor, for this application. Can you explain why you made a resonant circuit?

Note in real life, the loop will be resonant due to the stray capacitance interacting with the inductance.

...and you call THAT a magnetic personality?

Did you use semirigid coax for E field shielding?

You seem to be jumping through a lot of hoops, just to inductively charge a cellphone.

-- "For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." (Richard Feynman)

In my personal opinion, just do it both ways. That is both good engineering and good science. The ability to cross check is a MAJOR = plus. ?-)

Jessica Shaw a écrit :

There's no way you can _measure_ your field that way. You have to use an untuned loop if you want any accuracy, otherwise your "measurement" will depend on:

Your 12uH inductor has 7.54 ohm impedance at 100kHz. If you have say 28Vpk_pk (10Vrms) @ 100kHz on your inductor that's about

At a resistivity tempco about 0.4%/K for copper, which will almost be you Q tempco, I bet you'll easily exceed the accuracy you want to measure your field (at least its uniformity).

More, your 18 turns (=1.58m) of AWG36 will have a 535mR DC resistance, meaning that your best quality factor will be Q=7.54/0.535=14

That means that your open loop (untuned) voltage will be at least

Some pages missing, notably page 20, which has some of the Matlab code.

As I found when I tried to get it into Octave, runs as far as it goes.

Apparently scanned by the janitor.

I am not trying to measure the magnetic field with the LC resonant circuit. I am trying to measure it with one turn 1" inch untuned ( with out any inductor and capacitor ) diameter loop just like the ARL paper suggested. Please read the PAPER!

I am sending this loop to a company for calibration. They will put this loop in a know magnetic field of 10 guass and will let me know how much voltage they see at the output of the loop. My question is that Is this a good approach or not?

Thanks

jess

Why not simply buy or rent a fluxmeter?

I will buy one for less than 300 dollars if it can meaure magentic field in the range between 75 to 100KHz.

jess .

Jessica Shaw a écrit :

Oh, no need to shout, I was just trying to help. Good luck.

I decided to take a peek at the HMC1043 on Honeywell's site:

Is my version of Acrobat reader broken (V 7.0 on Linux) or is Honeywell suffering from fontitis?

Opens just fine with Acrobat v7.1 (on XP) ...Jim Thompson

Looks peachy-keen with the Foxit and PDF-Xchange viewers (current versions, WinXP). Very vanilla embedded font sets (Arial, Time New Roman, and Marlett).

Displays fine with Ghostscript 8.54: Loading NimbusSanL-Regu font from /usr/share/ghostscript/fonts/n019003l.pfb...

Acrobat is often broken. I use Foxit under XP, and they have a free Linux version. Foxit is a zillion times faster and more stable than Acrobat.