How to use this resource
Please download the PDF of this resource using the Download PDF link in the banner above.
Below are interactives which support the resource. The interactives can be launched by clicking on the images.
Some resources have pre-requisites; where this is the case, you'll be able to access any required resources through the Pre-requisites section.
Topic areas
Electrical and electronic engineering
- AC true, reactive and apparent power
- AC power factor
Mathematics
- Vector addition
- Pythagoras’ theorem
- Trigonometry
Pre-requisites
‘AC phasors and fault detection’ resource to introduce phasor diagrams and the relationship between resistance, reactance and impedance.
Problem statement
The relationship between voltage and current in an AC system is determined by the impedance of the circuit.
The impedance can consist of a resistive component and a reactive component, the latter of which introduces a
phase difference between voltage and current.
How does the phase difference affect the power drawn by the circuit (in this case a motor)?