In this module you are going to learn about The basics of Alternating Current (AC), Inductance and Capacitance

Alternating Current (or AC for short)

In an ac circuit, not only does the current change direction periodically; the voltage also periodically reverses. The rate of reversal may range from a few times per second to many billions per second.

Read up on Sine wave AC
once you have a good understanding of the shape formula used to describe a Sine wave AC waveform read about the Amplitude of a Sine Wave
The most important things to remember about the Amplitude of AC Sine waves are the relationships between V_{rms ,}V_{p and} V_p-p You will need to know how to convert between the various values and understand what each form represents.
Now read about the Frequency and Period of a Sine wave
It is important to understand the relationship between frequency and time because this is the key to understanding Wavelength.

Wavelength
The distance travelled by the sine wave during one period is called the wavelength, the symbol used to represent wavelength is the Greek letter Lambda which looks like . wavelength is usually measured in meters.

All electromagnetic energy has one thing in common: It travels, or propagates, at the speed of light.
This speed is approximately 300000000 (or 3.00 × 10⁸ ) meters per second in a vacuum. Electromagnetic-energy waves have a length uniquely associated with each possible frequency. The wavelength () is simply the speed of propagation divided by the frequency (f) in hertz.

The formula for wavelength for Radiowaves is

= 300000000 / Frequency in Hz
Which can be more conveniently represented as

= 300/ Frequency in MHz

Memorise this formula as it is the basis of many exam questions.

Next you need to learn about Phase angle
Phase angle will become important in module 3 and is the key to understanding tuned circuits later on in the course.

In module 1 you learned the formula for power, Here is an explenation of power in AC circuits.

To understand inductance you must first learn The fundamentals of Electromagnetism

Magnetic fields are closed fields that surround a magnet. The field consists of lines of magnetic force or flux. It exhibits polarity, which is conventionally indicated as north-seeking and south-seeking poles, or north and south poles for short. Magnetic flux is measured in the SI unit of the weber, which is a volt second (Wb = V s).

The field intensity, known as the flux density, decreases with the square of the distance from the source. In SI units, flux density is represented by the tesla (T), which is one weber per square meter
(T = Wb / m 2 ).

Magnetic fields exist around two types of materials. First, certain ferromagnetic materials contain molecules aligned so as to produce a magnetic field. Lodestone, Alnico and other materials with high retentivity form permanent magnets because they retain their magnetic properties for long periods. Other materials, such as soft iron, yield temporary magnets that lose their magnetic
properties rapidly.

The second type of magnetic material is an electrical conductor with a current through it. The needle of a compass placed near a wire carrying direct current will be deflected by the magnetic field around the wire. This phenomenon is one aspect of a two-way relationship: a moving magnetic field whose lines cut across a wire will induce an electrical current in the wire, and an electrical current will produce a magnetic field.

Now on to inducance
Introduction to inductance
You will not need to learn the formulae in the introduction page for the experimenter's exam but it will be useful to understand the terms used.

Self inductance
Note that the unit of inductance is the Henry. Note also the Phase Difference between the Voltage and the current with the AC waveform at the end of the article, in this case the Current is Lagging the voltage by 90 degrees. We will be covering this properly in module3.

Study the following chapter about the L/R time constant
Pay paticular attention to the shape of the Charge and discharge curves

Now would be a good time to learn about Series and parallel circuits using inductors, see the following pages
Series Inductor Circuits
Parallel Inductor Circuits
Note the similarities between inductance calculations and the resistance calculations you learned in module 1

Capacitance Introduction
A capacitor is most simply defined as two conductors separated by a dielectric.
Capacitor Charge and Discharge
pay particular attention to the way in which a capacitor charges and discharges in an AC circuit
Capacitor Formulas
Note the relationships between the Dielectric constant, Plate spacing, plate area and capacitance

Charging, Discharging and time constant in Capacitor Circuits.
Note the similarities and differences with self inductance.

Now would be a good time to learn about Series and parallel Circuits using Capacitors.

Parallel Capacitor Circuits
Series Capacitor Circuits

Note the similarities and Differences! Between Capacitor Calculations and the resistance calculations you learned in Module1.