On Fri, Nov 28, 2008 at 05:26:49PM -0600, John Hasler wrote: > lee writes: > > But how do know that there is voltage when you cannot measure it or > > otherwise make evident that there is? As far as I understand it, you > > cannot do that without current flowing. You can do it for water pressure > > without water flowing, but I don't see how you could do it for voltage > > without flow. > > You could use a potentiometer (not the kind you are used to: > <http://en.wikipedia.org/wiki/Potentiometer_(measuring_instrument)>) or
A wheatstone bridge? > you could measure the force exerted on a capacitor plate. Both these > methods are used in standards work. Usually, though, you would just use a > voltmeter with an input impedence larger that the leakage-resistance of ^^^^^^^^^ impedance > the wires connecting it to the source. Sensitivity? -- Chris. ====== I contend that we are both atheists. I just believe in one fewer god than you do. When you understand why you dismiss all the other possible gods, you will understand why I dismiss yours. -- Stephen F Roberts -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]