Science Buddies: "Ask an Expert"

OK so I'm assembling a wire recorder project but I haven't got the record head it working as of yet

I have read all the posts regarding it on the forums here and not found a direct answer

my question is, can someone give me the exact measurements of a known 'good' ferrite bead that they have working in their project ?

My ferrite bead is about 16mm diameter(measured across it looking down through the hole)
6mm tall (i cut it from a longer tube)
the center of the ring measures just under 8mm
and the cut gap is about 1mm

thanks for your time

Chris

Hi Chris,

There was an earlier message thread on this topic on sciencebuddies. Please consult:

http://www.sciencebuddies.com/science-f ... =29&t=3834

Does it help getting your ferrite bead to work? (or was it information you knew about already, something you tried, and it didn't work?)

Thanks.

Hi thanks for the reply

as I stated above I read all the posts that came up in the search engine on the site (that thread was one)

It didn't really answer any of the questions I asked above

by the photos on the project page my ferrite bead seems slightly bigger (it doesn't bunch up the magnet wire so much after 220 turns) and I wanted to ascertain what other people had found when carrying out this project

for instance the cut in my bead is about dead on 1mm is this to large?

the photo on the project page is slightly to small and has no frame of reference to work out dimensions of the bead used in the original

thanks again

I haven't had any luck getting a direct answer to this question, but I have a suggestion: there's a picture on the experiment page of a wound bead next to the recording wire. From the fact that the experiment calls for 34 gauge winding wire, you should be able to get a pretty good guess as to the size of the bead by scaling the picture. It's pretty small. Sorry not to be more help.

Thanks I figured as much

I would have been nice to get something more concrete
I can't quite fathom why the information isn't included in the project page it would have been simple to include some measurements

Hi Chris,

Judging from the links and comments in the third post in this topic (below), it sounds like your bead size falls in the range of those listed as "too big":
http://www.sciencebuddies.com/science-f ... =26&t=2604

You might have already seen this, but for others who follow in your footsteps, I'll mention that there is additional discussion about the issue of the size of the ferrite bead here (ninth post).
http://www.sciencebuddies.com/science-f ... 34&p=15792

I hope that helps.

Chris

hi thanks Chris I didn't twig I could use the part numbers to find there dimensions on the product page of the website

Ill try and convert those archaic Imperial measurements in to easy to use metric


anyway thanks form the UK

You're welcome. Good luck with the project (and archaic units of measurement), and please check back if you have any other problems, questions, or suggestions.
Chris

Hi Everyone - The "Recording on a Wire" project (https://www.sciencebuddies.org/science- ... p015.shtml) on the Science Buddies site has been updated to include information about the size of the ferrite beads that can be used for the project.

The materials list now includes this updated information:

"at least 5 ferrite bead cores, more if you want to experiment with the number of turns on the coil. For example, part # 495-3847-ND from Digi-Key. Other ferrite beads with similar dimensions (10.00mm O.D. x 6.00mm I.D. x 4.00mm L) should work too; "

Amy
Science Buddies