1. Circuits & Switches

2. Electricity Formed when an excess of positive or negative particles that are parts of atoms attempts to balance itself=electrical charge If the electric charge has a complete pathway, the charge flows The flow is called the electrical current The complete pathway is called an electrical circuit Circuits carry the electricity need to do a defined task The task is referred to as the electrical load

3. Recap Electrical charge – potential of electrons or protons to attract each other Electrical current – the movement of electrons from one atom to another Electrical load – any component or circuit that consumes power delivered to it by a power source Switch – any device that allows the flow of electricity in a circuit when turned on -either completes the circuit or pathway (turned on) or breaks it (turned off)

4. Creating a Circuit You need 4 essential components 1.Conducting path 2.Electrical load 3.Power source 4.Switch

5. Circuits In our homes some circuits are designed to carry electricity through light bulbs to light a room In a computer, circuits carry information during input, storage, processing and output

6. Digital Information Computers use integrated circuits (chips) that include many transistors that acts as switches Transistors are either ON or OFF Electricity is either flowing through the transistor or it isn’t, thus a circuit is either OPEN or CLOSED Something that can have only two states is called binary

7. Binary Binary number system represents two states 0 and 1 There are no 0s and 1s inside the computer Instead 0s and 1s represent the state of a transistor switch/circuit 0 = OFF 1 = ON The computer industry uses an 8-bit code representing letters and other symbols

8. Binary (cont’d) Each letter is given a numerical value that is converted into binary form Common code used on desktop computers is the American Standard Code for Information Interchange (ASCII) This standard uses an 8-bit code used to represent the characters used in written communication