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Current and voltage directions.

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alphacat

New Member
Hey, I wanted to ask you something please.
In university you learn that in resistor, the voltage's direction is opposite to the current's direction, but when you measure it with scope, they dont have 180 celsius deg. phase between them but 0.

How do you settle it?
Thanks.

 

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Sceadwian

Banned
Conventional current 'flows' from the + to the - lead. The actual electrons flow from the - to the + leads. Any help?
 
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smanches

New Member
I'm not the one to ask for theory, but how do they explain voltage having a direction? Voltage is just a difference in potential; a scalar value, no direction involved.

Current is the one that is often times misunderstood. I think most people think of current as the flow of holes through a circuit. That is opposite to the flow of electrons, from positive to negative. Again though, it's another scalar value, but together with Voltage can give the vector which we call electricity.

Again, just my un-theorized understanding of it all.

EDIT. I think they must be teaching electrons as voltage and holes as current. I guess that kind of makes sense from a physics point of view.
 
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Sceadwian

Banned
Smaches direction comes when you pick one as a reference, just like a ground in a circuit.. Physics and electronics chose differently. It doesn't matter because both flows occur simultaneously anyways they're just inverse.
 

alphacat

New Member
Thank you very much.
In a voltage source, the direction is going like this:

So if we relate to the current as electrons' flow, then the current flows in oppsite direction to the voltage's direction.
Does it mean than that the power factor of the voltage source is negative, and therefore the active power of the voltage source is negative?
 
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smanches

New Member
I guess I was just thinking of direction and thinking them meaning that voltage flows in a direction. Electricity flows; voltage and current are just the two parts of that equation. Neither of them flow by themselves.

Just me thinking too much again. :p
 

smanches

New Member
Thank you very much.
In a voltage source, the direction is going like this:

So if we relate to the current as electrons' flow, then the current flows in oppsite direction to the voltage's direction.
Does it mean than that the power factor of the voltage source is negative, and therefore the active power of the voltage source is negative?
First define what your current is. In electronics, current usually flows from positive to negative. In physics, they are usually discussing the flow of electrons, which means negative to positive.

This is the second time I've heard 'active power' in terms of a power source. Still don't know what they mean by it. Not sure what they mean by 'power factor' in this context either.
 

alphacat

New Member
Hey,
Active Power = RMS_Current * RMS_Voltage * Power_Factor.
Power_Factor is cos(phase), where 'phase' is the phase between current and voltage.
 

Sceadwian

Banned
Alphacat I thought this question was answered in the other thread. The ONLY way to have a negative active power source is to attach to something that is generating electricity.
 
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Sceadwian

Banned
We'll see you in the over unity threads here inside a few months =)
 

alphacat

New Member
Unless i'll be banned :
forever
for:
posting rubbish
and then will be banned for:
two days
for:
posting more rubbish.
 
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