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The Power Formula is used to compute the Power, Resistance, Voltage or current in an electrical circuit. The standard metric unit of power is the Watt. Solved Examples. Problem 1: An electric machine makes use of 300 J of energy to do work in 10s. How much power does it use? Answer: Known: Work done = W = 300 J, Time taken t = 10 s.
Learn the Power Formula. We’ve seen the formula for determining the power in an electric circuit: by multiplying the voltage in “volts” by the current in “amps” we arrive at an answer in “watts.” Let’s apply this to a circuit example: How to Use Ohm’s Law to Determine Current.
P = W / t. The standard metric unit of power is the Watt. As is implied by the equation for power, a unit of power is equivalent to a unit of work divided by a unit of time. Thus, a Watt is equivalent to a Joule/second. For historical reasons, the horsepower is occasionally used to describe the power delivered by a machine.
In this chapter we will be concerned with mechanical energy, which comes in two forms: kinetic energy and potential energy. Kinetic energy is also called energy of motion. A moving object has kinetic energy. Potential energy, sometimes called stored energy, comes in several forms.
Express electrical power in terms of the voltage and the current. Describe the power dissipated by a resistor in an electric circuit. Calculate the energy efficiency and cost effectiveness of appliances and equipment. In an electric circuit, electrical energy is continuously converted into other forms of energy.
Power is the rate at which energy of any type is transferred; electric power is the rate at which electric energy is transferred in a circuit. In this section, we’ll learn not only what this means, but also what factors determine electric power.
Table 1. Table method with power included. Power for any particular table column can be found using the appropriate Ohm’s power law equation. Power in Series and Parallel Circuits. Power is a measure of the rate of work.
The formula is Power = Current × Voltage: Power (P) is measured in Watts (W), Current (I) is measured in Amps (A), and Voltage (V) is measured in Volts (V). It takes both Current and Voltage to create Power! This is similar to water where power needs both flow (like current) and pressure (like voltage). See Electricity Water Analogy for more.
Power Formulas. No, not that type of Power Formula! Power is the rate of energy per time: P = Energy Time. Example: 3000 J of energy is used in 20 seconds, what is the power? P = 3000 J 20 s = 150 W. We can also change the formula this way: Start with: P = Energy Time. Energy is also Force × Distance: P = Force × Distance Time.
Average power is the power measured over a long period, i.e., when Δ t in the equation for power is very large. One way to calculate this is to find the area under the power vs time curve (which gives the total work done) and divide by the total time.
