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| ScopeMeter 199C Current Measurement |
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| gerp124:
Hello and thanks in advance for any advice you can offer- I'm definitely feeling like an idiot. I dabble in electronics, so there's a lot I don't know, but this one is driving me nuts: How do you measure current with a Fluke 199C ScopeMeter via direct connection- without a clamping probe? 1) Since I've already tried, I hope it's possible, and if not, I hope I haven't damaged anything. 2) If it _is_ possible, then I think all I need to know is what sensitivity I should select. Should this be obvious? I did read the manual- it simply states that I should choose the correct sensitivity for my current probe. Again, thanks for any reads/responses :-) |
| noidea:
Any oscilloscope (scopemeter or not) can only measure voltage, when you connect a clamp probe to a scope input it still is measuring the voltage output from the clamp probe and depending on the setup scaling the mV output from the clamp to display the result it in Amps or milliamps. The scopemeters have the benefit of the isolated input channels making this a lot easier and safer if this relates to mains/line voltage, If you don't have a current clamp probe then it is still possible to measure current using a resistor in the circuit as a current shunt and using a channel of the scope to measure the volt drop across the shunt. Have a read of this Fluke scopemeter application note on power measurement for a bit more of an understanding, however the setup and scaling is going to depend on the resistance of the shunt and that is going to depend on what current you are trying to measure. https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahUKEwjz6Pfqo9PfAhXEc94KHSmSD2UQFjAAegQIBxAC&url=https%3A%2F%2Fdam-assets.fluke.com%2Fs3fs-public%2F2140127_a_w.pdf&usg=AOvVaw3OdaRyNVUw51vNoBxP9bgQ |
| mahi:
--- Quote from: gerp124 on January 04, 2019, 01:15:53 am ---How do you measure current with a Fluke 199C ScopeMeter via direct connection- without a clamping probe? 1) Since I've already tried, I hope it's possible, and if not, I hope I haven't damaged anything. --- End quote --- See noidea's reply for more information how to measure current with an oscilloscope but to answer your question, no, you did not damage the ScopeMeter. Toggling between V(olt) and A(mpere) on the ScopeMeter only affects the displayed units and scale. Internally it's always measuring voltage. So the "current" you measured with the ScopeMeter was just the voltage multiplied by the set current clamp sensitivity. |
| jeroen79:
--- Quote from: noidea on January 04, 2019, 04:38:52 am ---The scopemeters have the benefit of the isolated input channels --- End quote --- They are isolated from the rest of the world but not from eachother. Keep that in mind if you want to measure with 2 channels. |
| SG-1:
You can make your own shunts using various lengths & gauge wire for low frequency work. Look through the scope menu to get the various values it can use directly. Be careful to use a gauge size that will not change appreciably with temperature due to the electric current & keep them straight, no coiling, that will add inductance. |
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