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Alright, I am experimenting with some cable design and got to the part of measuring parallel capacitance (Cp) and realized I am missing some information.
When we read the shared information from cable manufacturers, Ls, Cp & DCR is often shared.
My question is this: I understand that Cp is measured between 2 leads with one of the ends open, but that is not what I am wondering about. Say you have more than 2 conductors (typical), each conductor pair has Cp.
Am I suppose to only look at the Cp between one pair or am I suppose to add all the pairs together ?
Ex): There are 5 conductors, which amounts to 4 pairs, so: Cptot = C1+C2+C3+C4
Many thanks in advanced.
Oneminde
Alright, I am experimenting with some cable design and got to the part of measuring parallel capacitance (Cp) and realized I am missing some information.
When we read the shared information from cable manufacturers, Ls, Cp & DCR is often shared.
My question is this: I understand that Cp is measured between 2 leads with one of the ends open, but that is not what I am wondering about. Say you have more than 2 conductors (typical), each conductor pair has Cp.
Am I suppose to only look at the Cp between one pair or am I suppose to add all the pairs together ?
Ex): There are 5 conductors, which amounts to 4 pairs, so: Cptot = C1+C2+C3+C4
Many thanks in advanced.
Oneminde
it depends. Considering crosstalk you must measure between the pair of conducters. To estimate capacitive loading of a single strand you should parallel all other strands.
Right and I understand that. What I am wondering about is which of does are most common when we look at the Cp from a cable manufacturer ?
You do not say what type of cable you are measuring so if I understand this correctly you had a multi strand cable and are looking at Cp of the pairs in the cable.
So if this is the case then measure each pair (+ & -) that will carry the signal. Capacitance to any other wire in the group will cause cross talk from the C coupling.
So if this is the case then measure each pair (+ & -) that will carry the signal. Capacitance to any other wire in the group will cause cross talk from the C coupling.
Better yet, I can show you 🙂 - and I measured between a pair. Its an experiment, a way for me to learn. This is single conductor measurements. Measurements between a +/- is not done.
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OK I see.
What are you using to measure? Really need a 4 wire bridge for accurate measurements and you need allow thermal stabilization.
If you move the conductors further apart the C will drop.
What are you using to measure? Really need a 4 wire bridge for accurate measurements and you need allow thermal stabilization.
If you move the conductors further apart the C will drop.
Its a simple but okayish DMM - DEER EE DE-5000.
Yes I know about the determining factor for C, I locked the position when Lp = NaN 🙂
4 wire bridge - explain ? - I think I know what you mean, energies both conductors and measure Cp between a + & - conductor ... 🙂
Yes I know about the determining factor for C, I locked the position when Lp = NaN 🙂
4 wire bridge - explain ? - I think I know what you mean, energies both conductors and measure Cp between a + & - conductor ... 🙂
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Btw, I did move the foil further apart after Lp=NaN but the Cp changed marginally so didn't see the point in gaining only a few percentage lower Cp but a doubling in distance.
The trend is fairly clear, lower gauge wire makes a larger impact on Cp as well as RDC/Rs... kinda neat discovery for me 🙂
The trend is fairly clear, lower gauge wire makes a larger impact on Cp as well as RDC/Rs... kinda neat discovery for me 🙂
I was wrong... Bridge LCR
Auto LCR Digital Electric Bridge Resistance Capacitance Inductance + ESR Meter 913544170279 | eBay
Auto LCR Digital Electric Bridge Resistance Capacitance Inductance + ESR Meter 913544170279 | eBay
I have the same bridge. It is exceptionally good for the price. Before I retired I worked in a Calibration Lab and I check this against our standards and it measures within 0.3% and repeatability is within 2 counts.
This bridge does 4 wire measurements with Kelvin clips. This is a far more accurate method of direct measuring.
This bridge does 4 wire measurements with Kelvin clips. This is a far more accurate method of direct measuring.