Electricity. whether two charges attract or repel depends on whether they have the same or opposite...

14
Electricity

Transcript of Electricity. whether two charges attract or repel depends on whether they have the same or opposite...

Electricity

• whether two charges attract or repel depends on whether they have the same or opposite sign

• unit of measurement for charge is the coulomb (C)– one electron has a charge of

0.00000000000000000016 coulombs

Charge

Current

• comes from the motion of electrons• is the rate at which electrons flow past a point

on a circuit– measured in units called amperes, or amps (A)

current

Voltage• a measure of electric potential energy• voltage is an electrical force

– measured in volts (V)• a difference in voltage provides the energy that

causes current to flow

Circuits• current only flows when there is a complete

and unbroken path, or a closed circuit

• A circuit with a break is an open circuit and will trop the current. Example: light switch

• series circuit– current can only take one path, so the

current is the same at all points in the circuit

• parallel circuit– the current can take more than one path– each branch works independently

• Resistance– The measure of how strongly a wire or other

object resists current flowing through it– The amount of resistance determines the

amount of current for a given voltage. Higher resistance = less current.

Full Current ½ current 1/3 current

Conductors, Semiconductors and Insulators– Conductors: can conduct, or carry, electrical current.

The resistance is low. Example: metals

– Insulator: current cannot pass easily through these materials because the insulate, or block, the flow of the electrical current. Examples: rubber, glass, wood

– Semiconductor – between a conductor and insulator. They carry electricity better than an insulator but not as good as a conductor. Examples include: silicon (used in computer chips, TV, portable radios)

Insulator