Power In and AC Circuit

Watts Law:

• Power in watts is found by multiplying Volts x Amps

True Power:

• This formula only applies when Voltage and Current are in phase.  In an AC this happens only an a resistive circuit
  
  
• In an AC circuit with Capacitance, and Inductance, power is stored and released in the inductors and capacitors 90 degrees out of phase with true power
  
  
• A Watt meter must be used to find true power in an AC circuit

Apparent Power:

• In an AC circuit and resistance, capacitance, and inductance the power consumed is not equal to the product of source voltage and current
  
  
• The product of source voltage and current is called Apparent Power

Power Factor:

• Power factor gives the relationship between true power and apparent power

Power Factor Formula

• Power factor in resistive circuit is 1
• Power in an AC Cct P = E x I x PF