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P=E^{2}/R is a formula that you would use if you only know the voltage and the resistance.

Example: E = 120v R = 20 P = E^{2} / R P = 120v^{2} / 20 P = 14400v / 20 P = 720w

P=I^{2}*R is a formula that you would use if you only know the amps and the resistance.

Example: I = 15A R = 12 P = I^{2} * R P = 15A^{2} / 12 P = 225A / 12 P = 2700w or 2.7kw

Power: The rate of doing work. The faster the given amount of work is accomplished, the greater the power required. Power's unit is the watt(w) 1000 watts = kilowatt(kw) Fact: The power company charges you for the amount of power you use.

^{.}P=I*E is a formula that you would use if you only know the amps and the voltage.

Example: I = 5A E = 120v P = I * E P = 5A * 120v P = 600w

Amps: the intensity of current(moving electrons) in the circuit. The Ampere unit is the Amp(A) Fact: It takes less than one amp to kill a person.

^{ }I=P/E is a formula that you would use if you only know the watts and the volts.

Example: P = 100w E = 120v I = P / E I = 100w / 120v I = .83A

^{ }I=E/R is a formula that you would use if you only know the volts and the resistance.

Example: E = 208v R = 12 I = E / R I = 208v / 12 I = 17.3A

^{ }I=(P/R) is a formula that you would use if you only know the watts and the resistance.

Example: P = 250w R = 2 I = ( P / R ) I = ( 250w / 2) I = ( 125 ) I = 11.18A

Volts: Potential difference or electrical pressure of the circuit. The voltage unit is the Volt(V) Fact: Voltage does not kill people.

^{ }E=I*R is a formula that you would use if you only know the amps and the resistance.

Example: I = 10a R = 12 E = I * R E = 10a * 12 E = 120v

^{ }E=P/I is a formula that you would use if you only know the power and the amps.

Example: P = 100w I = 2a E = P / I E = 100w / 2a E = 50v

^{ }E=(P*R) is a formula that you would use if you only know the power and the resistance.

Example: P = 30w R = 12 E = (P * R) E = (30w * 12) E = 18.97v

Resistance: The property of a material that causes it to oppose the movement of electrons. The resistance unit is the Ohm()

^{ }R=E/I is a formula that you would use if you only know the voltage and the amps.

Example: E = 120v I = 3a R = E / I R = 120v / 3a R = 40

^{ }R=E^{2}/P is a formula that you would use if you only know the voltage and the power.

Example: E = 120v P = 40w R = E^{2} / P R = 120v / 40w R = 3

^{ }R=P/I^{2} is a formula that you would use if you only know the power and the amps.

Example: P = 60w I = 3a R = P / I^{2} R = 60w / 3a^{2} R = 6.67