How Does Resistance Distribute Along the Length of a Resistor?

[Physicslearner500039]

Hi All,

I have this clarification, if I have a resistor element of any value and if the physical length of the resistor is say L. Does the resistance of the element increases from 0 at the beginning to R at the end of the resistive element that is L, or it is the average, or it is located at one point, could somebody please explain me this? Similarly if a current I is flowing through the resistive element the voltage drop say Vr keeps increasing from 0 to the Vr at the end of the element or how it is?

Thanks in advance,
regards,
Satya

 

[vk6kro]

It depends on the resistor, but if the resistance material is uniform, then this is true:

if I have a resistor element of any value and if the physical length of the resistor is say L. Does the resistance of the element increases from 0 at the beginning to R at the end of the resistive element that is L,

Wire wound resistors are similar, but the resistance increases in steps as you go from turn to turn. If you followed the wire all the way around the resistor, then the resistance increases as you go from one end to the other.

There are potentiometers of both types which allow you to connect to various ponts on a resistor and gradually change the resistance or the ratio of resistances..

 

[Physicslearner500039]

So can I say that a voltage drop across a resistor (by passing a current) is the sum of the small voltage drops within the resistor ?

Thanks in advance,
Regards,
Satya

 

[vk6kro]

Yes, you could say that.

The small parts of a resistor are just like having a lot of small resistors in series, so you could regard each of them as producing a small voltage due to the current flowing in it.

 

[alphysicist]

Hello Satya,

The resistance of an element is a measure of its ability to resist the flow of current. It is typically represented by the letter R and is measured in ohms (Ω). The resistance of an element is determined by its physical characteristics, such as length, cross-sectional area, and material composition.

In the case of a resistor element, the resistance does not increase from 0 at the beginning to R at the end. Rather, the resistance is constant throughout the entire length of the element. This means that the voltage drop across the element is also constant, regardless of where it is measured along the element's length. Therefore, the voltage drop Vr at the end of the element is the same as the voltage drop at any other point along the element.

To understand this concept, it may be helpful to think of a resistor element as a pipe through which water (current) flows. The resistance is like the diameter of the pipe - a wider pipe will allow more water to flow through at a given pressure (voltage). However, the resistance remains the same throughout the entire length of the pipe.

I hope this helps clarify your question. Please let me know if you have any further questions.

Best,