RTE 005 - electricity and magnetism

Electrostatics

the study of stationary electric charges

electrodynamics

the study of electric charges in motion

Electrification

• can be created by contact, friction, or induction

• it is due to the movement of negative electric charge

Electron

the smallest unit of electric charge

coulomb (C)

the fundamental unit of electric charge

6.24 × 10^18 electron charges

1 C is equal to ______

Atoms

have neutrons, protons, and electrons

protons

are positively charged atoms

electrons

are negatively charged atoms

outer

Electrons are located on the _____ edges of atoms… they can be moved.

concentration

A _____ of electrons in an atom creates a net negative charge.

stripped

if electrons are _____ away, the atoms becomes positively charged.

Static electricity

What is this electral potential called?

static electricity

• the build up of an electric charge on the surface of an object

• the charge builds up but does not flow

• _____ is potential energy. It does not move. It is stored.

Static discharge

Occurs when there is a loss of static electricity due to three possible things:

Friction, conduction, and induction

these are the three possible things why static discharge occurs.

friction

rubbing

induction

through an electrical field (not direct contact)

current

electricity that moves

current

flow of electrons from one place to another

amperes (amps)

current is measured in _____

kinetic energy

what energy is current?

circuits

we can control currents by ____

circuit

it is a path for the flow of electrons. uses wires.

Direct Current (DC) and Alternating Current (AC)

2 types of currents are:

Direct Current (DC)

where electrons flow in the same direction in a wire.

Alternating Current (AC)

electrons flow in different directions in a wire

Rectifier

a mechanical device that converts alternating current to direct current

Rectification

is the process of converting alternating current to direct current (AC – DC )

series circuit and parallel circuit

2 types of circuits are:

Series circuits

The components are lined up along one path. If the curcuit is broken, all components turn off

total resistance

The _____ is equal to the sum of the individual resistances (rules for series circuit)

same; equal

The current through each circuit elements is the _____ and is _____ to the total circuit current. (rules for series circuit)

equal

The sum of the voltages across each circuit element is _____ to the total circuit voltage. (rules for series circuit)

Parallel circuits

there are several branching paths to the components. If the circuit is broken at any one branch, only the components on that branch will turn off.

equal

The sum of the currents through each circuit element is _____ to the total circuit current (rules for parallel circuit)

same; and equal

The voltage across each circuit is the _____ and is _____ to the total circuit voltage (rules for series circuit)

inverse of the sum

The total resistance is the _____ of the reciprocals of each individual resistance.(rules for series circuit)

Conductors

material through which electric current flows easily.

metal and water

examples of conductors are:

insulators

materials through which electric current cannot move.

styrofoam, rubber, plastic, and paper

examples of insulators are:

semiconductors

A _____ is a material that under some conditions behave as an insulator and in other conditions behaves as a conductor.

Silicon (Si) and Germanium (Ge)

examples of semiconductors are:

Superconductivity / superconductors

_____ is the property of some materials to exhibit no resistance below a critical temperature (Tc).

niobium and titanium

examples of superconductors are:

Resistance

The opposition to the flow of an electric current, producing heat.

greater; less

The _____ the resistance, the _____ current gets through. (resistance)

Good; low

_____ conductors have _____ resistance. (resistance)

ohms

Resistance is measured in _____

material of wire

aluminum and copper have low resistance

thickness

the thicker the wire the lower the resistance

length

shorter wire has lower resistance

temperature

lower temperature has lower resistance

voltage

• The measure of energy given to the charge flowing in a circuit.

• The greater the voltage, the greater the force or “pressure” that drives the charge through the circuit.

amps

measures how much

volts

measures how hard

Electromagnet

a magnet made from a current bearing coil of wire wrapped around an iron or steel core.

generator

• a machine that changes mechanical energy to electrical energy

• Usually use moving magnets to create currents in coils of wire.

motor

a device that changes electrical energy to mechanical energy that can do work