Electric Current Chapter 34 Flow of Charge Electricity

Electric Current Chapter 34

Flow of Charge • Electricity (charge) – Flow of electrons – Caused by electric potentials (differences in charge) • Charge will flow from negative to positive end

Electric Current • Flow of electric charge per time (I= q/t) – Movement of electrons • Conductors have electrons that are free to move – Measured in amperes (A)

Voltage • Provides “electric pressure” (force per area) to move electrons between two terminals in a circuit • Causes current • Measured in volts (V)

Electric Resistance • Resists to the flow of charge – Dependent on conductivity (inversely) and thickness of wire (inversely) as well as temperature (direct) • The longer the wire, the more resistance • The thinner the wire, the more resistance – Measured in Ohms (Ω)

Ohm’s Law • Current= voltage resistance The greater the resistance, the less the current The greater the voltage, the greater the current

Types of Current • Direct current (DC) – Flow of charge always flows in one direction • Example: batteries (have negative and positive • Alternating Current (AC) – Electrons in the circuit move first in one direction and then in the opposite direction • Example: electricity through your home – 3 wires (+, -, neutral)

Source of Electrons in a Circuit • Source of electrons does not come from a power outlet but from the conducting circuit material (wires) – Energy flows from outlets to the circuit causing electrons to move

Electric Power • Rate at which electrical energy is converted into another form of energy • Electric power = current x voltage – Measured in Watts (W)