What is the difference between VA and Watts?
Power is measured in Watts, using the symbol W (named after James Watt – the inventor of the steam engine) In A DC (Direct Current) circuit W = VA This is also true in an AC circuit with resistive elements only (no inductance or capacitance). Inductors & capacitors cause the current in an AC circuit to be out of phase with the voltage (current waveform leading voltage for capacitors & lagging for inductors). The phase angle between voltage & current waves is called the power factor & expressed as cos (for most practical transformer related applications cos is usually 0.
