1. Chapter 6.3 Notes Electrical Power

2. Voltage causes charges to move in circuits. This movement creates work. How fast the charge does work is called Power.

3. Power = Current x VoltagePower Pwr = I x V

4. A circuit has a power supply for a laser that has a current of 15 amps when the voltage is 110 volts. What is the power? Pwr = I x V Pwr = 15 amps x 110 volts Pwr = 1650 A·V or Watt

5. When a circuit resists changes in the charge flow there are 3 equations that are used: Pwr = I x V Pwr = I 2 R Pwr = V 2 /R

6. A Current of 2.2 A has a Resistance of 5. What is the power? We have current (I) and Resistance (R), which equation? Pwr = I 2 R Pwr = 2.2 2 x 5 Pwr = 24.2 Watts

7. A current of 2.2 A has a Voltage of 110 V, what is the power? We have current (I) and Voltage (V), which equation? Pwr = I x V Pwr = 2.2 x 110 242 WattsPwr = 242 Watts

8. A Voltage of 110 V, has a resistance of 5. What is the power? We have voltage (V) and Resistance (R), what equation? Pwr = V 2 /R Pwr = 110 2 /5 Pwr = 2420 watts

9. Power companies sell energy and not Power. When you use an electrical device you pay the energy used by the device.

10. Equation for energy and power: Energy = Power x change in time E = Pwr x ∆t

12. If our current is 1.5 Amps for a TV and we use a 120 V outlet to run the TV for 8 hours, how much energy will we use? E = pwr x t Pwr = equation? Voltage or Current Pwr = I x V = 1.5 x 120 = 180 Watts Convert 8 hours to seconds E = 180 watts x 28,800 secs E = 5,184,000 watts