Slide 1: S.MORRIS 2006 ELECTRICAL CIRCUITS More free powerpoints at www.worldofteaching.com Slide 2: What is an electric current? An electric current is a flow of microscopic particles called electrons flowing through wires and components. + - In which direction does the current flow? from the Negative terminal to the Positive terminal of a cell. Slide 3: simple circuits Here is a simple electric circuit. It has a cell, a lamp and a switch. To make the circuit, these components are connected together with metal connecting wires. cell lamp switch wires Slide 4: simple circuits When the switch is closed, the lamp lights up. This is because there is a continuous path of metal for the electric current to flow around. If there were any breaks in the circuit, the current could not flow. Slide 5: circuit diagram cell switch lamp wires Scientists usually draw electric circuits using symbols; Slide 6: types of circuit There are two types of electrical circuits; SERIES CIRCUITS PARALLEL CIRCUITS Slide 7: The components are connected end-to-end, one after the other. They make a simple loop for the current to flow round. SERIES CIRCUITS If one bulb ‘blows’ it breaks the whole circuit and all the bulbs go out. Slide 9: PARALLEL CIRCUITS The current has a choice of routes. The components are connected side by side. If one bulb ‘blows’ there is still be a complete circuit to the other bulb so it stays alight.