Below are a series of interactives which support the resource. Each interactive can be launched by clicking on its image, or through links in the PDF itself.

Some resources have pre-requisites; where this is the case, you'll be able to access any required resources through the Pre-requisites section.

- AC true, reactive and apparent power
- AC power factor

- Vector addition
- Pythagoras’ theorem
- Trigonometry

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)?

The above interactive allows you to change the frequency, resistance, inductance or capacitance, and displays the appropriate impedance effect or supply voltage needed.

The above interactive allows you to change the frequency, resistance, inductance or capacitance, and displays the relevant true, apparent and reactive powers.

Resources

**Electrical & Electronic:** AC theory | Resistance, reactance and impedance

**Mathematics:** Phasors | Vector addition | Pythagoras' theorem | Trigonometry

**Prerequisites:** None

Resources

**Electrical & Electronic:** AC Theory | Resistance, reactance and impedance | Potential divider in an AC circuit | Low pass and high pass filters

**Mathematics:** Vector addition | Pythagoras' theorem | Trigonometry | Phasor multipilcation and division (stretch)

**Prerequisites:** AC phasors and fault detection

Resources

**Electrical & Electronic: **Ohm's law | Electrical power | Kirchhoff's current law (1st law) | Kirchhoff's voltage law (2nd law) | Resistors in series and parallel

**Mathematics:** Simultaneous equations

**Prerequisites:** None

Resources

**Electrical & Electronic:** Voltmeter | Waveforms | Amplitude | Time period | Frequency | Instantaneous values | Peak-to-peak value | Peak value | Combining waveforms | Root mean square (rms) value | Phase angle | Form factor | Average value

**Mathematics: ** Square and square roots | Basic arithmetic

**Prerequisites: ** None

Resources

**Electrical & Electronic:** The solenoid | Magnetic flux | Magnetic flux density | Magnetomotive force | Field strength | Permeability

**Prerequisites:** None