Why does resistance increase with current

What happens to power when resistance increases? Does higher resistance mean less voltage? Why does the resistance increase as the voltage increases? What would cause high resistance in a closed electrical circuit? How resistance is directly proportional to length? What happens to current when area increases? Does more electrons mean more current? What happens to current when the length of conducting wire is doubled? Does resistance increase with length? Previous Article What year did Karl Marx die?

However, the electron is also slowed down when interacting with the resistor which heats up the resistor. The higher the resistance, the more intensively do the electrons interact with the resistor and the slower they are. Since electrons are repelling each other, this cannot be counteracted by more electrons going through the resistor. You can compare this situation to two basins of water at different levels voltages connected by a thin tube with a sponge inside the resistor.

The less porous the sponge, the slower the water flow the current. Note that there also exist current sources , which produce a constant current.

If a resistor is connected to such a current source, the voltage will increase such that the target current is reached. The higher the resistance, the higher the voltage and the more heat is disposed into the resistor. In the water analogy, such a current source corresponds to a pump working at a fixed rate, no matter how much pressure is needed to pump the water.

Sign up to join this community. The best answers are voted up and rise to the top. Raising the resistance is equivalent to making the passage harder to go through. So the difference of concentrations also increases — the voltage. If I add in a resistor to a circuit, the voltage decreases. The circuit with the higher resistance will allow less charge to flow, meaning the circuit with higher resistance has less current flowing through it. The current is directly proportional to the voltage and inversely proportional to the resistance.

This means that increasing the voltage will cause the current to increase, while increasing the resistance will cause the current to decrease. What happens to resistance when length is doubled? From the equation, we understand that resistance is directly proportional to the length of the conductor and inversely proportional to the crossectional area of the conductor.

Doubling the length doubles the resistance. Resistance measurements are normally taken to indicate the condition of a component or a circuit. The higher the resistance, the lower the current flow. All conductors give off some degree of heat, so overheating is an issue often associated with resistance.

The lower the resistance, the higher the current flow. The moving electrons can collide with the ions in the metal. For example, a high resistance design would require a long copper wire and the resistor would be large.

The same resistor could be made with a short length of nickel alloy wire, resulting in a much smaller device. However, when a high precision resistor is required, it is easier to trim resistance by removing a few inches of a low resistance wire, than by trimming millimeters of high resistance wire.

We measure electrical power in Watts. In a resistive circuit, power is calculated by squaring the current and multiplying that value by the resistance. Because resistors impede the flow of current, they generate heat. If the resistor operates within its power rating, the heat is harmlessly dissipated into the surrounding environment.

But, if we exceed the wattage rating, the resistor cannot dissipate the excess heat, and its temperature rises. The resistor will fail, usually by acting as a fuse and breaking the circuit. If the resistor is used in a high temperature environment, its power rating must be lowered, or "derated. The resistance of all materials changes as their temperature changes. If the temperature is lowered, resistance typically declines. In fact, if cooled sufficiently, the material becomes a "superconductor" with no significant resistance.

Increasing the temperature typically increases resistance. The temperature coefficient of resistance TCR of wire or a resistor relates the change in resistance to the change in temperature. The temperature coefficient of resistance, then, tells you how much the resistance changes ppm if the temperature changes one degree Centigrade. Sometimes, we measure temperature in degrees Fahrenheit. But today, degrees Centigrade is more common and acceptable.

Special wire alloys are formulated to have special temperature coefficients. These, and other alloys allow us to "tailor" the resistor to desired characteristics in applications where temperatures change. In the same application, a resistor made with Evenohm wire would increase to only ohms.