1. Electric Circuits17.4

2. Electrical Safety Tips Make sure insulation on cords is not worn Do not overload circuits Do not use electrical devices while hands are wet or while standing in water Never put objects other than a plug into an electrical socket

3. Parts of an Electric Circuit Parts – Energy source – A load – Wires – Sometimes a switch There must be a complete path for the electrons to follow from the energy source, through the circuit and back to the energy source (closed circuit) An open circuit does not provide a complete path to enable electron flow.

4. Series Circuit All parts of a series circuit are connected in a single loop. All loads in the circuit share the same current Many bulbs would be dimmer than few bulbs in the circuit If you unscrew one bulb it opens the circuit and the other bulbs go out. Useful in wiring burglar alarms

5. Parallel Circuit The loads in a parallel circuit are on separate branches (each one providing an alternate path for electrons to follow) The loads in a parallel circuit do not share the same current. Each light glows at full brightness regardless of the number of bulbs. If you unscrew one bulb, the others stay lit. Uses: household electrical needs.

6. Circuit Safety Circuits fail through short circuits or overload. Fuses or circuit breakers protect against circuit failure by opening the circuit and stopping the electron flow. Charges in a circuit flow through the fuse. If current is too high, the thin strip of metal burns through, opening the circuit Circuit breaker is a switch that automatically opens if the current is too high.