How do voltage and current combine to determine electrical power?

[polekitten]

Why does electrical power = voltage x current? I understand power is the rate of doing work or the rate of energy transfer but how does that relate to voltage an current?

I know current is the flow of charge and voltage is a difference in charge between 2 points.

 

[axmls]

Because voltage = joules/coulomb and
current = coulombs/second so

Voltage * current = joules/second

Which is the definition of power.

 

[Svein]

Why does electrical power = voltage x current?

I prefer to state Power dissipated = R*I². This is correct both for DC and AC.

 

[jim hardy]

voltage is a difference in charge between 2 points.

er, uh, make that "voltage is a difference in potential"

Be very rigorous about learning your basic units .