EMF and computers

[sysD]

I'm learning about electromagnetic fields.

 

My question is this:

 

If a current running through a wire produces a magnetic field, why does current in computer hardware not strip data from the HDD?

Is the magnetic field produced simply not strong enough? I'm not too sure of standard amperage in computer parts.

[lesolee]

My question is this:

 

If a current running through a wire produces a magnetic field, why does current in computer hardware not strip data from the HDD?

Is the magnetic field produced simply not strong enough? I'm not too sure of standard amperage in computer parts.

 

This is a very good question. The answer is that the computer is designed so that doesn't happen!

In the first place what you do in a good design is to run the "go" and "return" wires next to each other. In a DC circuit the positive and negative conductors are run next to each other. The magnetic field at a distance from this pair is very small. The field would be even less if the two conductors are twisted together, a "twisted pair".

 

I would expect the hard drive itself to have magnetic shielding. An iron, mu-metal or radiometal cover would give good magnetic shielding. (I don't know the specifics of what is actually done.)

[Enthalpy]

Single wires without an iron core produce an induction too small for a hard disk drive. Or it needs >10kA at 10mm of the magnet - this is how magnets are made. The biggest current in a PC feeds the CPU core, it's slightly over 100A.

 

Hard disk drives are not shielded. Aluminium foundry and sheet.