On Jan 22, 19:16, Hans Franke wrote:
> Subject: Re: OT: Alien Media (was Disasters and Recovery)
> Excuse me if I interupt, but you are talking about measuring
> a specific voltage. But thats completly independant from the
> definition. Only if you want to define Volt based on some
> specific reproduceable effect - but thats not necesaty. To
> get all electrical units you just need the 7 basic SI units
> (Length, Weight, Time, Current, Temperature, Brightnes (?)
> and Mol (sorry, no idea how to translate Stoffmasse)) and
length metre m
mass kilogram kg
time second s
electric current ampere A
thermodynamic temperature kelvin K
luminous intensity candela cd
amount of substance mole mol
> only one is an electric unit (the Ampere). And only these
> 7 units have to be defined on specific, reproducable effects.
> 1V is defined as 1 kg m^2 / A s^2.
As Hans implies, all other units are derived from these seven (and the two
angular measures). But the volt is defined as kg m^2 / (A s^3) -- Hans
lost a "per second" (Hertzlos, I suppose ;-).
--
Pete Peter Turnbull
Dept. of Computer Science
University of York
Received on Fri Jan 22 1999 - 16:51:17 GMT