How Does a Resistor Affect Voltage Drop in a Circuit?

In summary, the voltage across a resistor is determined by the power going into the resistor and the maximum voltage allowed in the circuit. Using the equations V=IR and P=IV, the voltage can be calculated by substituting the values for current and resistance. In a circuit with multiple resistors, voltage division is used to determine the voltage across a specific resistor. More information is needed to provide a complete answer.
  • #1
bhsmith
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I'm curious the amount the voltage would drop across a resisitor.
If you know the power going into the resistor and the maximum voltage allowed is say, 50V. How would that resistor effect the voltage? I understand the voltage would decrease, and when substituting and solving equations the new voltage would be sqrt(Power*Resistance). Is there anything else someone could add so I can better understand this? Thank you.
 
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  • #2
Odd wording of a question...but I'll try.

KVL = Kirchoffs Voltage Law states that the sum of the voltages across the loads in a loop must equal the source.

If you are saying you have a 50 volt source and one resistor, then all 50 volts drops across that resistor.
The current is then simply V=IR.

Power is based off of V=IR...not the other way around.
P=IV, so once the I and V are established from V=IR...there you go. Or you can use P=I^2*R or P= V^2/R

If there is more than one resistor, say two...then voltage division is used.
The voltage across the resistor you are interested is R1/(R1 + R2) * the voltage source.
 
  • #3
bhsmith said:
I'm curious the amount the voltage would drop across a resisitor.
If you know the power going into the resistor and the maximum voltage allowed is say, 50V. How would that resistor effect the voltage? I understand the voltage would decrease, and when substituting and solving equations the new voltage would be sqrt(Power*Resistance). Is there anything else someone could add so I can better understand this? Thank you.

For a proper answer, you would need to define the circuit (a diagram?). It's not clear what your actual question is.

But, if you apply 50V from an ideal power supply across a resistor then that defines the volts and the power. If the supply is not ideal then you'd have to give more details (as above)
 

FAQ: How Does a Resistor Affect Voltage Drop in a Circuit?

1. What is voltage drop across a resistor?

When current flows through a resistor, some of the electrical energy is converted into heat and the remaining energy is used to push the current through the resistor. This results in a decrease in voltage between the two ends of the resistor, known as the voltage drop across the resistor.

2. How is voltage drop across a resistor calculated?

The voltage drop across a resistor can be calculated using Ohm's Law, which states that voltage (V) is equal to current (I) multiplied by resistance (R). In other words, V = IR. This means that the voltage drop across a resistor is directly proportional to the current flowing through it and the resistance of the resistor.

3. Why is voltage drop across a resistor important?

Voltage drop across a resistor is important because it affects the performance and efficiency of an electrical circuit. If the voltage drop is too high, it can cause a decrease in the amount of current flowing through the circuit, which can lead to a decrease in the overall performance of the circuit. Additionally, excessive voltage drop can also cause overheating and damage to the resistor.

4. What factors affect the voltage drop across a resistor?

The voltage drop across a resistor is affected by the current flowing through the resistor, the resistance of the resistor, and the type of material the resistor is made of. Other factors that can also affect voltage drop include temperature, the length and thickness of the resistor, and the type of circuit the resistor is being used in.

5. How can voltage drop across a resistor be reduced?

There are several ways to reduce voltage drop across a resistor. One way is to decrease the current flowing through the resistor by using a higher resistance value. Another way is to use a thicker and shorter resistor, as this can decrease the resistance and therefore the voltage drop. Additionally, using materials with higher conductivity can also help reduce voltage drop.

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