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Current through a coil in a DC circuit

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 Author Topic: Current through a coil in a DC circuit  (Read 372 times)
UneXisted
Newbie

Posts: 3

 « on: April 03, 2012, 03:33:51 AM »

I would like to measure the current through a coil in a DC circuit, but I'm not sure how to accomplish this. I cannot put a sense resistor in between and the coil is my only option to indicate for the current. I was thinking about measuring the voltage over the coil, but I'm not sure how the voltage relates to the current for this coil.

Do you have any ideas?
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Hero999
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Electronics God

Posts: 2472

 « Reply #1 on: April 03, 2012, 04:58:49 AM »

You need to know both the current and voltage,in order to calculate the resistance, for more information look up Ohm's law.
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UneXisted
Newbie

Posts: 3

 « Reply #2 on: April 03, 2012, 06:08:18 AM »

In this case we are talking about DC current. I want to design a circuit that enables me to log the DC current that flows through the coil.

Therefore I need a measurement method to measure the current.
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UneXisted
Newbie

Posts: 3

 « Reply #3 on: April 04, 2012, 05:01:04 AM »

Another way would be to derive the current by the number of turns of the coil. Deriving the current by the resistance is not possible you guys say? due to the AC current. I have a spare motherboar with the same coil that i can unsolder. I can use it to measure the characteristics if needed.

The only option I have is to use a Hall Effect sensor I think, but thats my last solution because i have to place it inside a computer. THere is a great chance that interference will occur.
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Hero999
Global Moderator
Electronics God

Posts: 2472

 « Reply #4 on: April 04, 2012, 05:11:17 AM »

Another way would be to derive the current by the number of turns of the coil. Deriving the current by the resistance is not possible you guys say? due to the AC current. I have a spare motherboar with the same coil that i can unsolder. I can use it to measure the characteristics if needed.
But I thought you were talking about DC current?

Deriving the DC current is easy: you need to know the resistance and voltage and use Ohm's law.

Calculating the AC current is also not difficult but you need to know the inductance too.

Quote
The only option I have is to use a Hall Effect sensor I think, but thats my last solution because i have to place it inside a computer. THere is a great chance that interference will occur.
A Hall effect sensor will work but for AC it'll need to work up to the frequency being measured.

But why do it the hard way? It's DC so measure the resistance of the coil, the voltage across it and calculate the current.
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I also post at:
http://www.silicontronics.com

I do not answer private messages asking for help because no one else can: benefit from advice I may give or correct me if I'm wrong.

Please ask on the open forum if you have a question: if I know the answer, I'll be happy to help.

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