Question

What is the formula to calculate power of resistor? Can we measure power of resistor
without the value of voltage? What is power rating used for?​

Answer 1

Answer:

What is the formula to calculate power of resistor

ANSWER: First, we use Ohm’s law ( V = I × R ), to find the current through the resistor.

• The voltage across the resistor is V = 9 V.

• The resistance of the resistor is R = 100 ?.

Therefore, the current through the resistor is:

I = V / R = 9 V / 100 ? = 90 mA

Then, we can use the power rule ( P = I × V ), to find the power dissipated by the resistor.

• The current through the resistor is I = 90 mA.

• The voltage across the resistor is V = 9 V.

Therefore, the power dissipated in the resistor is:

P = I × V = 90 mA × 9 V = 0.81 W

Can we measure power of resistor

ANSWER :The Resistor Power Triangle

The above power triangle is great for calculating the power dissipated in a resistor if we know the values of the voltage across it and the current flowing through it. But we can also calculate the power dissipated by a resistance by using Ohm's Law.

What is power rating used for?​

ANSWER: Power converting equipment

In devices that primarily convert between different forms of electric power, such as transformers, or transport it from one location to another, such as transmission lines, the power rating almost always refers to the maximum power flow through the device, not dissipation within it.