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### Topic: Measuring capacitance of a dual cable with arduino (Read 182 times)previous topic - next topic

#### brkblbn

##### Mar 14, 2019, 10:08 pm
Can anyone help me???

How can I measure capacitance of a dual cable or any cable with arduino. I found this
https://circuits4you.com/2016/05/13/capacitance-measurement-arduino/ but this is just measuring the unknown capacitor.

Thanks

#### jremington

#1
##### Mar 14, 2019, 10:15 pmLast Edit: Mar 14, 2019, 10:19 pm by jremington
If the cable has two leads, or an inner and outer conductor, use those two in the same circuit. Makle sure the wires are not connected at the far end.

You may have to change the resistor values, as the cable capacitance will usually be in the pF to nF range (unless it is quite long).

Hint: you can look up the capacitance per unit length for most cables and wiring. For example, 12 AWG "zip" cable for household lamps and audio speakers has capacitance of about 60 pF/meter.

#### brkblbn

#2
##### Mar 14, 2019, 10:49 pm
First, Thank you for your message.

So, you say I keep the same circuit and source code but change capacitor with dual cables. Does it work

like that? I don't think that the measuring will be accurate.

#### jremington

#3
##### Mar 15, 2019, 12:01 amLast Edit: Mar 15, 2019, 12:02 am by jremington
Quote
I don't think that the measuring will be accurate.
Obviously, you have no basis for thinking that, until you have actually tried the experiment. Use a known capacitance for tests.

#### brkblbn

#4
##### Mar 16, 2019, 02:10 pmLast Edit: Mar 16, 2019, 02:14 pm by brkblbn
I tried to do the experiment but I do not understand how to implement the cables to the circuit. Connections may be wrong.

#### jremington

#5
##### Mar 16, 2019, 11:41 pmLast Edit: Mar 16, 2019, 11:43 pm by jremington
Quote
If the cable has two leads, or an inner and outer conductor, use two AT THE SAME END in the same circuit.
Make sure the wires are not connected at the far end.
https://learn.sparkfun.com/tutorials/capacitors/all

#### brkblbn

#6
##### Mar 17, 2019, 10:25 pm
Thank you for your helpful advice but I already know how capacitor works. I just do not know implementing

the design using arduino

#### jremington

#7
##### Mar 17, 2019, 11:06 pmLast Edit: Mar 18, 2019, 12:25 am by jremington
Quote
I already know how capacitor works
No, you don't, because you don't understand that a cable with two or more leads IS a capacitor.

What is so difficult to understand about connecting two leads of a two wire cable to a circuit?

Maybe this picture will help:

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