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Another curious question  Why is current proportional to voltage? 
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#1
Aug2214, 02:18 PM

P: 20

Hi guys I just want to know why is the current directly proportional to the voltage is that because voltage increase the speed of electrons?? or ,just increase the number of electrons?????
Thanks in advance 


#2
Aug2214, 02:50 PM

P: 20

And what does it mean when we say high or low potential



#3
Aug2214, 04:47 PM

P: 535

Current is only directly proportional to voltage in materials that obey Ohm's law.
You can look at it from a few standpoints. charge/time is the definition of a current. V = IR in an Ohmic material so you could say V is the required pressure to push I electrons/time through a resistor of resistance R. Potential is another word for voltage. So high potential is high voltage. You can think of it as kind of an analogy to high pressure or high potential energy. If you put a large potential across a small resistor you'll get a large current. ( I = V/R) 


#4
Aug2514, 02:07 AM

P: 13

Another curious question  Why is current proportional to voltage?
In each type of conductor there is an certain amount of free electrons. These electrons are permanently moving due to thermal energy. This happens also without electric field applied and it is random movement so overall current is zero. But when you apply some amount of external electric field then this movement of electrons begins to predominate in the direction of this field so the current starts to flow. So the number of electrons is always the same. The voltage only makes their random movement less random. And for beter conception thermal velocity is the order of 100000 meters/sec but the velocity caused by electric field is something like centimeters per hour.



#5
Aug2514, 03:32 AM

P: 20

So you mean when the voltage is high it creates stronger electric field and more electrons predominate in the direction of the field and more electrons mean more current right !??!!



#6
Aug2514, 04:50 AM

PF Gold
P: 161




#7
Aug2514, 05:31 AM

Sci Advisor
Thanks
PF Gold
P: 12,256

*Volts per metre 


#8
Aug2514, 04:53 PM

P: 535




#9
Aug2514, 05:28 PM

Sci Advisor
Thanks
PF Gold
P: 12,256

At least there is PF; available for nearly everyone in the World, these days. A bit fussy and pedantic at times, perhaps, but a good rock to anchor your EE learning to. 


#10
Aug2514, 06:57 PM

P: 535




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