- #36
sophiecentaur
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UltrafastPED said:I'm not clear what you are saying here. How would making a measurement change the nature of a device?
But if I were to use a voltmeter to measure the voltage drop across a resistor - then I need to make two connections, one on each end. If I were to use an ammeter to measure the current flowing through the resistor I would also need to make a connection at each end.
The connections can be shared if you don't require great precision; to get more accurate readings use the Kelvin technique.
But in either case you have four physical connections. The consolidation of wires into nodes implicitly assumes no resistance in the wires.
Is this your point? Nodes on a diagram are logical; connections are physical. The map is not the territory, but it is good enough for an initial analysis.
I learned the basics of Resistance measurement at School; nothing has changed about that, since, afaik. NAspook's two diagrams say all that's needed.
My "point" is that you introduced this "transresistance" as if it somehow distinguishes a 'resistor' resistor (Ohmic?) from any other conducting device (the electrons in a vacuum tube, for instance). For some reason, you introduced the 'four terminal' measurement to justify the 'transresistor' term to justify it. But the term is a complete red herring and refers to a four terminal device. It would surely have helped if you had just admitted that the term is not relevant to this thread.
My initial point was that Ohm's Law is not synonymous with the expression R = V/I and that people who know better should really be using the right terminology, in the interests of those who are trying to find out about it.