KVR Audio

xoxos · Post by **xoxos** » Tue Jun 14, 2011 3:51 am

if one is winding a coil, the first layer is easy. beginning, wind, end.

however, people often mention using multiple layers to increase the effect of a coil. what they omit is how this is accomplished.

given my appalling knowledge of electronics (it's not my fault really) i _assume_ that if you wind the second layer back over the first layer but in the opposite direction, you are reducing the field effect of the first layer. i also _assume_ this would be true if you ran the wire in a straight line back to the beginning and wound subsequent layers over it.. by crossing the direction of turning, aren't you screwing it up??

so.. i can only presume that the only effective way of actualising a multiple layer winding is to cut a separate length for each layer, solder them all at the beginning, wind them, then solder them all at the end, eg. creating 'nested coils in parallel,' which seems like a lot of work, ie. something people would mention if it were actually necessary.. soooo i am presuming my idea that winding a 2nd layer against the direction of the first must somehow be wrong.

i'd test it but i've had terrible luck with electronics so i end up reading it over and over because eg. my capacitor doesn't work so i can't actually make any practical observations..

tia,

noizetronic · Post by **noizetronic** » Tue Jun 14, 2011 6:50 am

xoxos wrote:i also _assume_ this would be true if you ran the wire in a straight line back to the beginning and wound subsequent layers over it.. by crossing the direction of turning, aren't you screwing it up??

Nope; no U-turn of the wire, no change of direction for the magnetic field.
So every industrial coil just is layer over layer, all wound the same direction.

egbert · Post by **egbert** » Tue Jun 14, 2011 7:02 am

Are you simply making a hand wound inductor or is it for a guitar pickup?

Layering is no problem. There were some copper coils used in high end hi-fi crossovers that used a thin copper sheet which spanned the full width of the coil. They were wound layer on layer like a roll of gaffer tape.

trimph1 · Post by **trimph1** » Tue Jun 14, 2011 12:59 pm

Hand coiled or machine coiled...just layer over layer..no turning back or U turning,,continue same direction as you were on first layer...

Some good information on coils and such...

http://www.mikroe.com/old/books/keu/03.htm

xoxos · Post by **xoxos** » Tue Jun 14, 2011 5:33 pm

i got this from another source.. the turns go in the same direction (clockwise/anti-) the wrapping doesn't need to (eg. from beginning to end) so once you get to the end you can continue wrapping in the other direction exactly as a spool of cotton is wound..

it's for a small emp gun to disarm rfids

folderol · Post by **folderol** » Thu Jun 16, 2011 6:29 pm

Hmmm. Are you intending to hit it with a fairly high amplitude pulses? If so wrap a thin sheet of tissue over each layer - leading the wire through the overlap. Provides extra insulation, and stops the layers getting mixed up - also gives you the chance to take a break from time to time

P.S.
As you are unlikely to have vacuum facilites, varnish the finished coil with shellac (French Polish). This, being very thin and light penetrates far better than conventional electrical varnishes.

P.P.S.
I'm one of the idiots who used to wind valve amplifier transformers by hand

xoxos · Post by **xoxos** » Thu Jun 16, 2011 6:42 pm

i'm going to be using big wire for this.

hot to wind a coil?