ABSTRACT
This chapter provides an introduction to electric circuits, initially introducing basic electrical diagram symbols, defining electric current, charge, potential difference and resistance and listing typical measuring instruments. For a continuous current to flow between two points in a circuit a potential difference or voltage V is required between them, a complete conducting path is necessary to and from the source of electrical energy. The fuse is a piece of wire which can carry a stated current, if the current rises above this value it will melt. Ohms law states that the current I flowing in a circuit is directly proportional to the applied voltage V and inversely proportional to the resistance R, provided the temperature remains constant. Conductors are materials that contain electrons that are loosely connected to the nucleus and can easily move through the material from one atom to another. Insulators are materials whose electrons are held firmly to their nucleus.
