Where to look for Magnetic Cores On-Line to buy?

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Enrique15

Joined: 08 Jan 2005
Posts: 57
Helped: 1
Location: Panama

02 Jul 2005 11:19 Where to look for Magnetic Cores On-Line to buy?

Hello, folks!

I'll appreciate if you can advice me of some website (or websites) that sell magnetic cores.

It's just that I want to make my own designs of "transformers", to apply the theory I've learned in college. And for doing so I need magnetic cores that have their specifications (for example, the "B-H curve"), so I can "calculate" the design.

Because I don't like very much the idea of being "guessing" in the calculations by using magnetic elements got from a repair shop or electronic store, where all the parts they have are taken from TVs or radios, and the person doesn't know nothing about "reluctance" or "flux" (for example).

Thanks for anything you can suggest me.

P.S. :
If I want to make a "Impedance-Coupling Transformer" to amplify an audio signal, so I'll need just a little current from my power supply because the transformer will amplify the current to feed my speaker...
The question is: Can I get SMALL magnetic cores to do such a transformer (because it won't need to be as big as the ones used for Power Supply transformers). Let's say, 3 cm (or 1 inch) of length. Are there in the Internet-market "little" magnetic cores for buying ??? Where can I get them ??

Regards.

funster

Joined: 30 Jun 2005
Posts: 234
Helped: 12

03 Jul 2005 7:13 Re: Where to look for Magnetic Cores On-Line to buy?

actually , you can buy ferrite core from those electronic store,

because your objective is studying ferrite core, you can measure

ferrite core's parameter by yourself.

for AL value, you can wrap ten turns of isolated conductor

onto ferrite core and measure the resulting inductance, then

you can calculation inductance per turn square.

for BS, you can apply a rectangle wave drive signal

to drive the coil with a little resistor in series,

you can increase the drive signal's amplitude gradually

and measure the voltage drop in the resistor,

if the voltage shape of this resistor suddenly increase,

then the point that ferrite core begin to satuarate

is find.

best regards

Enrique15 wrote:

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Enrique15

Joined: 08 Jan 2005
Posts: 57
Helped: 1
Location: Panama

06 Jul 2005 1:32 Re: Where to look for Magnetic Cores On-Line to buy?

Thanks a lot, Funster, for your reply.
It'll help me very much when studying and searching for inductance.

But besides that, if I wanted to buy an already measured Magnetic Core to build a Transformer (120V to 12V for example), where can I find tested cores with their measures in DATASHEETS (as if I'd be buying a transistor or a capacitor, they all have their tested values, and I can do calculations over the rest of the circuit using those measures, without doing them myself).

Of course it'll be interesting to search for induction, saturation, etc, of a core...

But if I want to get a core already measured, is there an On Line store where I could buy those ?

Thanks for your time and help, fellows.

Regards. Smile