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DC Theory: negative voltage (lemmy.world)

submitted 9 months ago by [email protected] to c/[email protected]

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I'm trying to understand what's happening in this circuit:

I------------------T1 (+333V)
I                 I
I                 R1(10K)
(pos)             I
1000V             I------------gnd (0V)
(neg)             I
I                 R2(10K)
I                 I
I                 IT2(-333V)
I                 I
I                 R3(10K)
I                 I
I-----------------IT3 (-666.7V)

I am learning basic DC theory from reading and sometimes I come across something I'd like to ask a question about, so:

In the above circuit, without the ground, the voltage across all components would begin at 10V and finish at 0V. By adding a ground, I'm basically saying "here is 0V" and everything gets redefined in reference to that point and I end up with a 10 volt circuit with +3.33 as it's highest voltage and -6.667 as it's lowest.
The electrons could care less, they still flow from the anode to the cathode of the battery under normal conditions, going from the highest potential to the lowest.
This example was only used to demonstrate voltage dividers. It revolved around worker protection present in aluminum processing. Each machine is in series and mobile grounds are used nearest the machine a worker is using. I assume that this allows the worker to have the least exposure to electrical shock as they are also at ground potential?

I actually think working though these questions has cleared everything up, but please, comment on anything I got wrong.

Also, sorry about the crappy drawing, the autowrap in this editor really made things tough to format

Thanks!

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[–] [email protected] 2 points 9 months ago (1 children)

And a quick followup:

If the ground was moved to the T3 junction than the battery's negative terminal would be common to ground and the voltages values across all loads would go back to being positive in regards to the battery's negative terminal (T1 = 1000V, T2 = 333V, T3 = 0V) ?

[–] [email protected] 4 points 9 months ago

Funny thing - regardless of where you put ground, all the voltages are positive relative to the negative battery terminal. Because voltages are always in reference to something (usually our reference is ground or the negative terminal). If you ever have to measure voltage, you'll notice the device has two probes - you can only measure voltage between two points.