Why not use The Scientific Method - try it! See what happens, then report back with your results. My first thought was "no way!", but if you can figure out how to "aim" it, you might be able to probe current in PC board traces.
But someone has to try it to find out if it's worth the bother. :-)
Good Luck! Rich
Oh, the WRITE heads are inductive; that's the wire pair you want to connect to. If you can see it. And, if you can weld really small wires.
You can do that, but the MR gives you (iirc) about 60 dB more signal.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
I'd be interested to see how it copes with multilayer PCBs.
A lot of the time, the current I'm interested in is in an inner layer.
--
"For a successful technology, reality must take precedence
over public relations, for nature cannot be fooled."
(Richard Feynman)
"Tom Del Rosso" wrote in news:j6o8kd$91t$1 @dont-email.me:
I would advise to use read/write heads from an old floppy, they have a handy size, and wont break so easely. Also you dont need a magnifier glass to see them......
[...]
Why don't you just build one as in Figure E1? Does not look difficult. I doubt a HDD head is suitable for this at all.
Arno
-- Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno@wagner.name GnuPG: ID: 1E25338F FP: 0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F
But MR effect is proportional to |B|, not to a component of B-vector, so you'll get odd effects (frequency doubling). I'm more comfortable with a search coil type probe. Heck, it doesn't even need any ferrite. I've made several for o'scope use, somehow they keep getting borrowed; like when I was in college, and my seasoned castiron frypans always wandered off when a roommate left...
I asked first if it was theoretically feasible, so it doesn't make sense to tell me that it isn't but I should try it anyway, but next time I have a scrap drive I'll give it a shot.
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Very good point indeed! I will ask the suppliers.
JB
Aehm, Figure E1 does not use a HDD head, i.e. I did not tell you to try anyways? Still, trying does nor hurt. But the comment that modern heads are magneto-resistive and hence do not use coils would at least require an adapted amplifier.
Arno
-- Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno@wagner.name GnuPG: ID: 1E25338F FP: 0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F
=20
I just scrapped a drive last month. Would you like the head stack?
?-)
Oh sorry. I Misread. Anyway it's interesting even when you learn you can't do something and why.
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On 10 Oct 2011 19:31:25 GMT, Arno put finger to keyboard and composed:
Here is a collection of HDD preamp datasheets:
The VTC and Philips datasheets are the more informative ones.
Here are HDD Read Channel datasheets:
- Franc Zabkar
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