# How to calculate the ampere

## Calculate electrical power

The more power is dropped across a resistor, the warmer it becomes. At a certain point it even breaks, i.e. it burns through. Here you can learn to calculate how much power is implemented. This article belongs to the field of electrical engineering or physics.

The electrical power "P" - for example at a resistor - is the product of current times voltage. The electrical power is given in watts. Before we take the formula apart, let us first refer to the articles that are required to understand electrical power. If the following things don't mean anything to you, you should read them first.

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### Calculate electrical power

As already mentioned, the electrical power is calculated from current · voltage and is specified in watts - W for short. Example: We have 20 volts of voltage applied and 10 amperes of current flowing. This means that the power is: P = U · I = 20 volts · 10 amps and thus P = 200 watts, or 200 W. Using Ohm's law, other formulas can also be used. Here are some formulas that can be used to calculate the electrical power.

Electric power Formula 1:

• Formula: P = U * I
• "P" is the power in watts
• "U" is the voltage in volts
• "I" is the current in amps

Electric power formula 2:

• Formula: P = I2 · R
• "P" is the power in watts
• "I" is the current in amps
• "R" is the resistance in ohms

Electric power formula 3:

• Formula: P = U2 : R
• "P" is the power in watts
• "U" is the voltage in volts
• "R" is the resistance in ohms

You can now insert the relevant information in the three formulas. Sometimes you also need Ohm's law (U = R · I) to determine further quantities.

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