Thanks for a quick response, it's now clear. Device I'm thinking of does not need big precision, I just want to measure kind of average current per period, to switch off some load before circuit breaker trips. On Sat, Jan 19, 2013 at 9:20 PM, Sean Breheny wrote: > Hi, > > No, it would not make a difference (or at least a very tiny one - it > might change the coupling between the primary _leads_ and secondary > _leads_ but it would not change the coupling between the primary and > the secondary coils, and the coupling between the coils will be far, > far larger and more dominant than the lead to lead coupling). > > For a toroidal transformer all that matters is the number of times > that a wire passes through the middle (hole). > > The situation which is less clear is when you have a core that has > more than one opening in it, like an E-I core in a transformer. In > that case, fractional turns counts are possible depending on how the > wire passes through the two openings. > > Sean > > > On Sat, Jan 19, 2013 at 2:01 PM, KPL wrote: >> Hi, >> >> I have ordered some current transformers, to measure average current >> in AC line. >> http://docs-europe.origin.electrocomponents.com/webdocs/0f47/0900766b80f= 47965.pdf >> >> I know usually power wire is just run through the core, but would it >> make any difference, if that wire made actually a full turn around the >> core, with ends crossing outside, not running through it twice? >> >> -- >> KPL >> -- >> http://www.piclist.com PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist --=20 KPL --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .