Presentation on theme: "Chapter 19: Electric Charges and Currents"— Presentation transcript:
1 Chapter 19: Electric Charges and Currents Electric Circuits and Electric Power
2 Electric CircuitsAn electric circuit provides a complete, closed path for an electric current.An electric circuit consists of a source of energy (voltage source), a load (resistance), wires, and a switch
3 Electric CircuitsSource: battery, thermocouple, etc.Load: uses electric energy (light bulb, appliance, etc.) - offers some resistance to current flowSwitch: opens and closes the circuitA current needs a closed path - if a switch is off, the circuit is open.
4 Parts of an Electric Circuit Source (Battery)Load (Light Bulb)
5 Electric CircuitsElectricity cannot flow through an open circuit. Electricity can only flow through a closed circuit.Closed CircuitOpen Circuit
6 Series and Parallel Circuits Series Circuit: circuit in which all parts are connected one after another. If there is a break, the entire circuit is opened and no current flowsParallel Circuit: circuit in which different parts are on separate branches. If there is a break, electrons can still move.
10 Series and Parallel Circuits Fuse: this strip of metal used for safety because when the current flowing through it becomes too high, it melts and breaks the flow of electricity- Protects against too much current flow (overload)- Once fuses burn out they must be replaced
11 Series and Parallel Circuits Circuit Breaker: reusable device that protects a circuit from being overloaded- Easier to use than fuses
12 Power = Voltage x Current Electric PowerElectric Power is the ratio at which electric energy is used by doing work, or by changing to a different form, such as heat or lightPower = Voltage x CurrentP = V x IWatts = Volts x Amperes
13 Kilowatt-hours = Kilowatts x hours Electric EnergyEnergy = Power x TimeE = P x tKilowatt-hours = Kilowatts x hours