IET
 Topic Title: SI definition of the unit of AMP current Topic Summary: Created On: 24 October 2016 01:18 PM Status: Read Only Linear : Threading : Single : Branch
Search Topic
Topic Tools
 View similar topics Print this topic.
 24 October 2016 01:18 PM acsinuk Posts: 210 Joined: 30 June 2007 The international unit of CURRENT is as defined below [The ampere is that constant current which, if maintained in two straight parallel conductors of cu rrent infinite length, of negligible circular cross-section, and placed one metre apart in vacuum would produce . between these conductors a force equal to 2 x 10-7 newton per metre of length. [CIPM (1946), Resolution 2, approved by the 9th CGPM (1948).] This definition is totally inadequate as it limits current to a single direction unit of force. It should be redefined as an area of spinning flux/current per square metre which when placed one metre apart in vacuum would produce . between these conductors a force equal to 2 x 10-7 newton per metre of length. 24 October 2016 02:52 PM ToniSM Posts: 336 Joined: 21 November 2006 Yet more drivel from the OP. ------------------------- Could there be a better way?In theory yes, but in practice? 25 October 2016 05:40 PM acsinuk Posts: 210 Joined: 30 June 2007 Sorry you are sceptical but If you look at Maxwells equations in Wikipedia then you will see the following definitions "Key to the notation Symbols in bold represent vector quantities, and symbols in italics represent scalar quantities, unless otherwise indicated. The equations introduce the electric field, E, a vector field, and the magnetic field, B, a pseudovector field, each generally having a time and location dependence. The sources are the electric charge density (charge per unit volume), ?, and the electric current density (current per unit area), J. The universal constants appearing in the equations are the permittivity of free space, ?0, and the permeability of free space, ?0." So current density is current per unit area of flux/current and voltage [E] will be volt per length at right angles. Result a volume of 3D magnetic flux energy. No where in Maxwells equations are electron particles mentioned as magnoflux energy can be a massless volume of electromagnetic light energy=hf. 29 October 2016 08:18 PM ectophile Posts: 754 Joined: 17 September 2001 Given that it's been around since 1948, I think somebody would have noticed by now if the existing definition of an ampere didn't work. That said, according to Wikipedia (so it must be true, obviously), the latest plan is simply to redefine the ampere as 1 coulomb per second, where 1 coulomb is approximately 6.2415093 x 10^18 electrons. ------------------------- S P Barker BSc PhD IEng MIET 04 November 2016 09:56 AM acsinuk Posts: 210 Joined: 30 June 2007 If an electron is a charged particle then it can't move at speed of light as a radio wave magnetic vibration or AC electric current does. We should resist this attempt to redefine electrical energy as a matter vibration and get current defined as a 2 dimension area of flux-current 06 November 2016 01:09 AM mapj1 Posts: 9691 Joined: 22 July 2004 The electrons don't need to move at speed c. When you add one electron at one end of a wire and L/c seconds later one drops out the other end, its not actually the same one, just the nearest one from great the pool of electrons dancing about the nuclei in the metal. About the only time you need to count electrons in and out is if you are designing for vacuum, like cathode ray tubes or particle accelerators, when you need to consider the ballistic velocity. I fail to see what problem you think you would be solving - Maxwell's equations are neither necessary nor desirable to define a unit of charge flux. If you are worrying about the magnetic field that surrounds a displacement current, say so, but then please also explain why you think its a problem. Also Voltage is a measure of scalar potential energy, not "E", which is the associated vector field.. ------------------------- regards Mike 12 November 2016 12:39 PM acsinuk Posts: 210 Joined: 30 June 2007 Currently energy is force times distance times time which is dimensionally ML/T^2*L*T=ML^2/T. same as kinetic energy. How can we have magnetic energy vibrations that travel at speed of light requiring to rely on mass M. Energy should be the fundamental unit that must be conserved whereas matter M is not.
 IET » Other and general engineering discussions » SI definition of the unit of AMP current Topic Tools
Statistics