A good grasp of first principles is essential before you embark on further studies in electrical engineering or electronics. These pages introduce fundamental electrical and electronic principles, starting with the nature of electricity itself and progressing to more advanced concepts such as the properties of semiconductor materials used to construct complex integrated circuits. The topics dealt with will include circuit analysis, direct and alternating current and electromagnetism. We will also examine a number of the components commonly found in complex circuits. Throughout these pages, the reader will be invited to "build" circuits of varying complexity in order to see for themselves how they work. It is suggested that simulation software is used to build the circuits. You may have access to a sophisticated software package such as Multisim from National Instruments. If not, there are some good open source software packages that will provide the necessary functionality. Have a look at Quite Universal Circuit Simulator (QUCS), an open source simulation package released under the GNU General Public Licence.