Current through resistor, with heat. What happens to the current?

In summary: But for real resistors, the resistance does change with temperature, so the current does change. Therefore, in summary, the current through a resistor will decrease if it heats up due to the increase in resistance. This is assuming the resistor is made of a material that has a positive temperature coefficient of resistance.
  • #1
rcmango
234
0

Homework Statement



Suppose a current of 1 A is flowing through a resistor. If this makes the resistor heat up, will the current through the resistor increase, decrease, or remain constant? Assume the voltage applied to the resistor is constant.

Homework Equations





The Attempt at a Solution



Please help me with this, I'm not sure, but I believe the current will decrease slightly because of the heat dissipated?
 
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  • #2
rcmango said:

Homework Statement



Suppose a current of 1 A is flowing through a resistor. If this makes the resistor heat up, will the current through the resistor increase, decrease, or remain constant? Assume the voltage applied to the resistor is constant.

Homework Equations





The Attempt at a Solution



Please help me with this, I'm not sure, but I believe the current will decrease slightly because of the heat dissipated?

The resistance of many electrical components changes with temperature. Certainly the resistance of a wire increases when it gets hotter, so if the resistor is actually made up of a length of wire you can expect that change in resistance - with an effect on the current I am sure you can predict.
 
  • #3
Okay, so as the wire heats up the resistance of the wire increases, this causes the current to decrease. Is that correct?
 
  • #4
rcmango said:
Okay, so as the wire heats up the resistance of the wire increases, this causes the current to decrease. Is that correct?

That sounds good.

EDIT: provided the resistor is made using wire.
 
Last edited:
  • #5
The current decrease is NOT because of the heat dissipated. For an ideal resistor that does not change resistance even if it heats up, the current doesn't change.
 

1. What is the relationship between current and heat in a resistor?

In a resistor, as the current increases, the heat generated also increases. This is due to the resistance of the material in the resistor, which causes a conversion of electrical energy into heat energy.

2. How does heat affect the flow of current in a resistor?

As heat increases, the resistance of the material in the resistor also increases. This leads to a decrease in the flow of current, as described by Ohm's law (V=IR). This means that a higher temperature can cause a decrease in the current flowing through a resistor.

3. Can the current through a resistor change due to heat?

Yes, the current through a resistor can change due to heat. As mentioned before, an increase in temperature can cause an increase in resistance, leading to a decrease in current. However, if the heat causes the resistor to melt or break, the flow of current will be interrupted or stop entirely.

4. What happens if the current through a resistor is too high?

If the current through a resistor is too high, it can cause the resistor to overheat and potentially damage or destroy it. This is why resistors have a maximum current rating, and it is important to use resistors with the appropriate ratings for a given circuit.

5. Is there a way to control the heat generated in a resistor?

Yes, there are several ways to control the heat generated in a resistor. One way is to use a larger resistor with a higher power rating to handle the heat. Another method is to use multiple resistors in parallel, which can distribute the heat among them. Additionally, using a heat sink or cooling fan can also help dissipate the heat generated by a resistor.

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