I've always been fairly sceptical they do anything!, but the idea is they form a lowpass filter on the cable, preventing very high frequencies travelling up the cable (it's just a ferrite core).
I've always been fairly sceptical they do anything!, but the idea is they form a lowpass filter on the cable, preventing very high frequencies travelling up the cable (it's just a ferrite core).
It presents an impedance to an AC signal. The impedance is a function of frequency and satisfies the following
Code:
Xl = 2 * π * f * L
where Xl is the Inductive Reactance
f is the frquency
and L is the inductance of the wire going through the core, one time only
As you can see whatever the inductance is it attenuates high frequencies better than low frequencies. As monitors use more and more pixels the vertical amplifiers need to cover a wider bandwidth. Do a back of the envelope calculation for your screen resolution times 30 frames per second to get some idea of the bitrate that may be present on the cable. As Nigel said however, I've never seen any actual data on what those slugs do for you. It's probably the Chicken Soup theory. Can't possibly hurt, and it might help.
In case you missed Bob Scott's succinct description, I take the liberty of repeating it again in hopes that repetition will make it through the thicker skulls.
Bob Scott said:
It is a one turn coil. Every pass through the core counts as one turn.