Batteryless current clamps?
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From: Fester Bestertester on 17 Nov 2009 03:18 I'm curious how the Fluke i200s current clamp probe can give mV output without the use of batteries. How is this done? If one is measuring 200A I can see how the magnetic field could generate enough current in the probe to support some high-impedance, low-draw circuitry. But when measuring on the low scale, say, 2 or 3 amps, how could the probe output a few hundred mV? (The clamp is spec'd to output 100mV / amp on the 20A low scale, 10mV on the 200A high scale.) Can someone explain this to me? I'm fascinated to see it's possible & curious to know how. Thanks.
From: Proteus IIV on 17 Nov 2009 05:46 On Nov 17, 3:18 am, Fester Bestertester <f...(a)fbt.net> wrote: > I'm curious how the Fluke i200s current clamp probe can give mV output > without the use of batteries. > > How is this done? If one is measuring 200A I can see how the magnetic field > could generate enough current in the probe to support some high-impedance, > low-draw circuitry. > > But when measuring on the low scale, say, 2 or 3 amps, how could the probe > output a few hundred mV? (The clamp is spec'd to output 100mV / amp on the > 20A low scale, 10mV on the 200A high scale.) > > Can someone explain this to me? I'm fascinated to see it's possible & curious > to know how. > > Thanks. CURIOUSITY KILLED THE CAT GO TO SCHOOL AND HEAR IT FROM THE HORSES NOUTH OR GO TO YOUR NEAREST TECHINAL BOOK STORE AND PURCHASE TEST METERS FOR DUMMIES I AM PROTEUS
From: Bill Sloman on 17 Nov 2009 08:39 On Nov 17, 11:46 am, Proteus IIV <proteus...(a)gmail.com> wrote: > On Nov 17, 3:18 am, Fester Bestertester <f...(a)fbt.net> wrote: > > > I'm curious how the Fluke i200s current clamp probe can give mV output > > without the use of batteries. > > > How is this done? If one is measuring 200A I can see how the magnetic field > > could generate enough current in the probe to support some high-impedance, > > low-draw circuitry. > > > But when measuring on the low scale, say, 2 or 3 amps, how could the probe > > output a few hundred mV? (The clamp is spec'd to output 100mV / amp on the > > 20A low scale, 10mV on the 200A high scale.) > > > Can someone explain this to me? I'm fascinated to see it's possible & curious > > to know how. > > > Thanks. > > CURIOUSITY KILLED THE CAT > GO TO SCHOOL AND HEAR IT FROM THE HORSES NOUTH > > OR GO TO YOUR NEAREST TECHINAL BOOK STORE AND PURCHASE TEST METERS > FOR DUMMIES > > I AM PROTEUS Try to find out where the caps lock is, and unlock it. At the moment you like more like Prostheticus. For future reference, if you don't know the answer to a question, it is not helpful to tell people that it is in some unspecified technical book somewhere. If you can identify a specific book that has a specific reference to the problem - with the ISBN for the book and the page or chapter reference for the helpful bit - you can earn brownie points without providing a direct answer. Unhelpful abuse counts as a waste of bandwidth. Raise you game or expect to be plonked. But don't worry if Jim Thompson plonks you - he plonks everybody who disagrees with him, which is probably one of the reasons he believes so many things that don't happn to be true. -- Bill Sloman, Nijmegen
From: Jim Yanik on 17 Nov 2009 09:06 Fester Bestertester <fbt(a)fbt.net> wrote in news:0001HW.C7279C6F0007F514B08A39AF(a)news.eternal-september.org: > I'm curious how the Fluke i200s current clamp probe can give mV output > without the use of batteries. > > How is this done? If one is measuring 200A I can see how the magnetic > field could generate enough current in the probe to support some > high-impedance, low-draw circuitry. > > But when measuring on the low scale, say, 2 or 3 amps, how could the > probe output a few hundred mV? (The clamp is spec'd to output 100mV / > amp on the 20A low scale, 10mV on the 200A high scale.) > > Can someone explain this to me? I'm fascinated to see it's possible & > curious to know how. > > Thanks. > > more turns on the pickup coil. -- Jim Yanik jyanik at localnet dot com
From: Jeroen Belleman on 17 Nov 2009 09:10
Bill Sloman wrote: > [...] > Try to find out where the caps lock is, and unlock it. At the moment > you like more like Prostheticus. > > For future reference, if you don't know the answer to a question, it > is not helpful to tell people that it is in some unspecified technical > book somewhere. > [...] You could have added a line for the OP, saying that a passive current clamp is a transformer, or some such. Jeroen Belleman |