A resistor is a two-terminal electronic component

1. Jul 10, 2008

Jin S Zhang

This is definition of resistor from Wikipedia.

1. " A resistor is a two-terminal electronic component that opposes an electric current by producing a voltage drop between its terminals in proportion to the current"

And this is another mention about Ohm's Law from a diagram of Wikipedia.

2. "A voltage source, V, drives an electric current, I , through resistor, R, the three quantities obeying Ohm's law: V = IR."

After reading these two statements, I got confused. From 1, I can assume that a resistor produces a voltage V to oppose an electric current. But, when I read 2, Voltage send current through resistor not produced by resistor. Could you please explain me about that. I just started learning Electricity. Thanks.

2. Jul 10, 2008

BryanP

Re: Resistor

The statements just tells you that since R is fixed, the voltage has to drop in proportion to the current passing through it.

You're basically driving a current with a certain voltage. Once you pass that current through resistor element R, it's going to oppose the current (the IR part), but because I is directly proportional to V (Ohm's Law V = IR), if you cause a drop in current using resistor R, then the voltage has to drop. Therefore, that is why you have a voltage drop after you pass through R.