Find direction of charge/current/electricity


Old 01-17-16, 03:38 AM
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Find direction of charge/current/electricity

2 scenarios ac and dc.

Given there is a DC 12 volt battery in a locked box with a positive and a negative wire powering an appliance using 1 amp in another locked box roughly 5 ft away from each other. How are you able to identify the direction of current, more specifically to identify which locked box the battery is in without cutting the power to the appliance, or without breaking open the boxes.

I am guessing there may be more magnetism in the line closer to the source of power but Im hoping there is a simple way to test it by the means of something like a diode. I guessed that there would be more temperature in the line closer to the source, but that is not posing reliable results.

The second scenario is exactly the same but the battery is a 120v ac single phase. Let me know your thoughts or solution. Preferrably cheap electro/mechanical solution.

Attached are 2 basic images describing the situation.


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Old 01-17-16, 09:15 AM
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Welcome to the forums. These are DIY help forums. If you are doing DIY we will be glad to help. We are not really for help with school questions or theoretical.
Old 01-17-16, 10:47 AM
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But to add, AC has no "direction". Look it up.
Old 01-17-16, 10:54 AM
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In this application.... AC or DC makes no difference. There will be a measurable voltage and a measurable current flow.

You can determine polarity if it's DC and you can measure the current flow of AC or DC but neither will tell you which device is in which enclosure.
Old 01-17-16, 03:13 PM
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Found a simple and effective solution by another member here who is a Genius. He stated for DC to create a solenoid or add and iron nail to it by wrapping one of the wires around it to measure the magnetic strength from the electromagnet. Did this at both ends just short of the enclosure and was able to correctly identify the location of the battery!
Old 01-17-16, 03:28 PM
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There will also be a measurable voltage drop across the wire, assuming you can probe those wires. If so, then the box with the very slightly greater voltage is the source, ac or dc.


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