[Prev][Next][Index][Thread]
What is proximity effect? (was:litz)
I need help to understand the nature of the proximity effect.
Proximity effect has been mentioned before, as a reason not to use thich
wire in secondary coils. I have come to understand it as that the HF
will not flow in the parts of the wire, that is close to each other. (As
if it was repelled, like magnetic lines of equal polarity)
If the wires are divided into 4 quadrants, this would mean that there
would be little current flowing in quadrants 1 and 3, like indicated in
ASCI below.
Please view in a fixed-width font such as Courier.
+++++++++++ +++++++++++
.++++ ++++ .++++ ++++
++.. +.. ++.. +..
++ .. 2 .. ++ ++ .. 2 .. ++
+ . ... + + . ... +
+ .. .. + + .. .. +
+ .. .. + + .. .. +
+ 1 ... + + 1 ... +
+ .. . 3 + + .. . 3 +
+ .. .. + + .. .. +
+ ... .. + + ... .. +
+ .. . + + .. . +
+.. 4 .. ++ +.. 4 .. ++
++ .. ++ ..
++++ ++++ ++++ ++++
+++++++++++ +++++++++++
If we now take the skin effect into consideration, there is not much
conductor left!, and perhaps quadrant 4 doesn`t conduct either?
But if this is true for a litz wire too, and the litz is twisted, then
the current will have to jump from wire to wire along the turns, making
the litz wire an undesirable choise on a level with braided shield.
Is this true, or false?
Cheers, Finn Hammer