background image

Learn about-





Revision 5.00 4th Sept. 2013


Prefer paper?

pdf logo

Click to download this complete module in PDF format.

Search with

Valid XHTML 1.0 Transitional

Step by Step logo

Module 5 - Phase and Phasors

The Magic of AC Circuits.

What you´ll learn in Module 5.

The AC circuits described in this module are some of the simplest in construction, consisting of only two or three components, but in their operation can seem almost magical, and are amazingly useful in so many ways. They might form the tuning circuit of a radio, and be used to improve the performance of amplifiers. They can greatly magnify alternating voltages or currents, and also reject radio interference. They may also be called "Tuned" or "Resonant" circuits and produce oscillations of a particular pitch or frequency in musical instruments. They are used to separate the high, low and mid range notes in a hi-fi speaker system. These same circuits perform functions like sensing a car as it approaches a traffic light, or help find buried precious metals with a metal detector.

Electronic systems

As you study this and the following modules, notice that the circuits described use two main components, inductors and capacitors, which in many ways seem to have opposite and complimentary effects. It is the way they are connected in a circuit, as well as their individual electrical values that are key to the many uses of these circuits. Although in many cases these basic inductor/capacitor combinations may now be replaced by new and usually smaller ceramic components, the basic principles of these LCR (inductor/capacitor/resistor) circuits are essential to understanding the operation of many electronic systems.