ferrite magnet as toroid transformer


by ramonegumpert
Tags: ferrite, magnet, toroid, transformer
ramonegumpert
ramonegumpert is offline
#1
Apr30-12, 10:23 PM
P: 182
Dear Experts

I have a 1.5 cm ring magnet, you know, the black color type of common low magnetic power magnet.

I wrapped 5 turns of copper wire around it on one side and then wrapped 10 rounds of another copper wire around it . I connected 5v battery to the 2 ends of the primary coil which is the 5 turn winding.

I then measured with volt meter the secondary coil. I did not see the output voltage at the secondary coil increase.

This is my noobie attempt. Please comment what could be wrong.

Can a ferrite magnet be used to step up voltage?

I want to step up the voltage by around 2 volts.

Many Thanks.

regards
Ramone
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vk6kro
vk6kro is offline
#2
Apr30-12, 10:34 PM
Sci Advisor
P: 4,003
Transformers only work on AC signals, so you would have to switch your battery current on and off through the primary winding to see anything on the secondary.

However, a ferrite magnet would be a poor choice for a transformer core. Better options would be normal ferrite or soft iron laminations from a transformer.
Bob S
Bob S is offline
#3
Apr30-12, 11:21 PM
P: 4,664
Are you talking about a toroidal "refrigerator" permanent magnet made of "hard" ferrite? You will need up to 300,000 amp-turns per meter. See attached table from http://www.what-are-magnets.com/10STRONTIUMCERAMIC.HTM
Attached Thumbnails
Hard_ferrite.jpg  

ramonegumpert
ramonegumpert is offline
#4
May2-12, 08:45 AM
P: 182

ferrite magnet as toroid transformer


Dear Experts
So , what is the recommended way to stepup a 5v dc battery pack to 8volts, occupying minimal space? Kindly please offer me an idea.

I have sen videos demonstrating how a joule thief can light up a 3v led using just 1.5v. I wonder can this toroid be modified/ used as-is to function as transformer ?

Yes, i am using a toroidal fridge magnet.
its ferrite but permanently magnetised, i think. Is the effect different than a non-magnetised ferrite?

Cheers
Bob S
Bob S is offline
#5
May2-12, 12:42 PM
P: 4,664
Quote Quote by ramonegumpert View Post
Dear Experts
So , what is the recommended way to stepup a 5v dc battery pack to 8volts, occupying minimal space? Kindly please offer me an idea.
Use a boost converter, which are transformerless:http://www.linear.com/products/step-...st)_regulators
Other mfgrs also make similar chips.
I have sen videos demonstrating how a joule thief can light up a 3v led using just 1.5v. I wonder can this toroid be modified/ used as-is to function as transformer ?

Yes, i am using a toroidal fridge magnet.
its ferrite but permanently magnetised, i think. Is the effect different than a non-magnetised ferrite?
Magnets are not suitable for transformers.
ramonegumpert
ramonegumpert is offline
#6
May5-12, 12:31 PM
P: 182
Thanks so much Bob S. I will get a ferrite toroid and try again.

Cheers :)
Bob S
Bob S is offline
#7
May5-12, 12:57 PM
P: 4,664
Quote Quote by ramonegumpert View Post
Thanks so much Bob S. I will get a ferrite toroid and try again.
If you need to make a toroid transformer circuit, be sure to use a soft ferrite. I personally would search for a boost regulator circuit from Linear.com, using a DIP package. How many milliamps do you need? I have built ferrite transformer circuits before, and the boost regulators are easier.
ramonegumpert
ramonegumpert is offline
#8
May7-12, 09:03 AM
P: 182
Dear Bob

Thanks for your reply.

I am looking at output of as high as 500 milliamps, input voltage of any between 9v to 12 v and output of 5.5 to 6v.

Is it possible to get free samples of 1 or 2 units for testing?

Thanks.

Regards
Ramone
vk6kro
vk6kro is offline
#9
May7-12, 10:59 AM
Sci Advisor
P: 4,003
You get free samples if someone thinks you might buy $500 worth of something. So, they ask who you work for and what your position is.

So, unless you are likely to buy a lot of something, you shouldn't ask for free samples.

Almost free, though, are these on Ebay:
http://www.ebay.com.au/itm/DC-DC-Con...item3f154a0adc

Synchronous rectification, Max efficiency up to 98%.
Input: 4.75-24V.
Output: 0.93V-18V ( Buck Mode, the input must be 2V higher than output ).
Output Current: continuous 2.5A ( Peak 4A).
Price about $3.50 US.

Which country are you in?


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