# Chapter 19: Electric Charges and Currents

## Presentation on theme: "Chapter 19: Electric Charges and Currents"— Presentation transcript:

Chapter 19: Electric Charges and Currents
Electric Circuits and Electric Power

Electric Circuits An 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

Electric Circuits Source: battery, thermocouple, etc. Load: uses electric energy (light bulb, appliance, etc.) - offers some resistance to current flow Switch: opens and closes the circuit A current needs a closed path - if a switch is off, the circuit is open.

Parts of an Electric Circuit

Electric Circuits Electricity cannot flow through an open circuit. Electricity can only flow through a closed circuit. Closed Circuit Open Circuit

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 flows Parallel Circuit: circuit in which different parts are on separate branches. If there is a break, electrons can still move.

Series and Parallel Circuits

Series Circuit

Parallel Circuit

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

Series and Parallel Circuits
Circuit Breaker: reusable device that protects a circuit from being overloaded - Easier to use than fuses

Power = Voltage x Current
Electric Power Electric Power is the ratio at which electric energy is used by doing work, or by changing to a different form, such as heat or light Power = Voltage x Current P = V x I Watts = Volts x Amperes

Kilowatt-hours = Kilowatts x hours
Electric Energy Energy = Power x Time E = P x t Kilowatt-hours = Kilowatts x hours