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Re: You're so quick in calculations...

They're fun...:-)

Now, take that 500 w amp, and go a bit more:

EMF = -N δΦ/δt N is turns..

Φ = BA = magnetic flux...A is area in meters.

At 10 cm from the wire, BA per cm2 is:

.316 gauss times 10-4 T/gauss = 3.1610-5 Tesla

As a 1 Khz signal 10 cm away, B = 3.16 * 10-5sin(ωt) Tesla

Rate of change of B is it's derivative.

ω = 2 pi f, or 6.283 103

so B = 6.283 103 * 3.16 * 10-5sin(ωt) Tesla

= 19.84 * 10-2sin(ωt)

If the feedback loop encompasses 1 cm2, 10 cm away from a current lead, then..1cm = 10-2 meters, 1 cm2 = 10-4 meters 2
EMF = - 1 * 19.84 * 10-2sin(ωt) * 10-4

= 19.84 * 10-6sin(ωt) volts....20 μvolts per square cm area.

Now, keep in mind star grounding techniques. They do not consider a time varying magnetic flux environment..It is not inconceivable to imagine 10 square centimeters of loop in a poweramp chassis in the grounding system. So, perhaps 200 μvolts??

And god forbid, some kind of inductor in the output..what, 10 turns? 2 millivolts?

Is that a worry??

Cheers, John




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  • Re: You're so quick in calculations... - jneutron 08:09:19 08/22/06 (1)


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