Hi snapdiode,
You probably know the density of the media that your drive reads and writes already but it is worth noting that the read/write head gap depends on the magnetic coercivity of the coating on the diskette, and that depends on the capacity of the diskette (360KB, 720KB, 1.44MB, 2.88MB, etc.).
The greater the storage capacity of the diskette the narrower the tracks have to be. Narrower tracks require magnetic material with higher coercivity to be coated on the diskette. In order to read and write these narrower tracks the magnetic field in the gap had to be higher which meant a thinner gap and the width of the gap had to be reduced to squeeze more tracks in.
In summary, the gap width depends on the data density of the floppy so your measurement and the reference may be referring to two different density heads.
Dennis Tillman W7PF
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-----Original Message-----
From: snapdiode via Groups.Io
Sent: Monday, December 23, 2019 7:51 PM
To:
[email protected]Subject: [TekScopes] OT: measuring tiny distances
Dear massed wisdom of this group, how would you measure the head gap of a floppy disk r/w head?
By counting pixels on a microscope pic I've arrived at the more or less believable 0.35 mils, or 0.009mm . One thing's for sure, it's tiny.
But that number is ten times smaller than the one reference I found that says it is 80 microns, or 0.08mm.
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Dennis Tillman W7PF
TekScopes Moderator
