introduction to electricity 2

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INTRODUCION to

Ignacio Anguera de Sojo

ELECTRICITY I

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Electric

Current and

Electrical

Energy

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Electrical energy

Energy: is the ability to do work, where work is done when a force moves an object.   Electrical energy: is energy that's stored in charged particles within an electric field.

Electric currentVoltageResistance

electric current and electrical energy

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1.- Electric Current

When you hear the word 'current,' what does it make you think of?

electric current and electrical energy

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When you hear the word 'current,' what does it make you think of?

electric current and electrical energy

Perhaps water flowing down a river?

1.- Electric Current

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When you hear the word 'current,' what does it make you think of?

electric current and electrical energy

A river current is the flow of water molecules

1.- Electric Current

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When you hear the word 'current,' what does it make you think of?

electric current and electrical energy

Electrical current instead of water molecules moving down a river, we have charged particles move down a conductor.

1.- Electric Current

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Electric Current: is the flow of charged particles through a conducting medium, such as a wire.

electric current and electrical energy1.- Electric Current

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Electric Current: How it works?

electric current and electrical energy

Atoms in a conducting material have lots of free electrons that float around from atom to atom and everywhere in between.

1.- Electric Current

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Electric Current: How it works?

electric current and electrical energy

Atoms in a conducting material have lots of free electrons that float around from atom to atom and everywhere in between.

The motion of these electrons is random, so there is no flow in any given direction.

1.- Electric Current

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Electric Current: How it works?

electric current and electrical energy

Atoms in a conducting material have lots of free electrons that float around from atom to atom and everywhere in between.

The motion of these electrons is random, so there is no flow in any given direction.

1.- Electric Current

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Electric Current: How it works?

electric current and electrical energy

When we apply a voltage to the

conductor, all free electrons move in the

same direction, creating a

current !!!!!!

1.- Electric Current

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Electric Current:  A curious thing….

electric current and electrical energy

While the electrical energy transfers at nearly the speed of light, the electrons

need 1 hour to move 1 meter!!!

1.- Electric Current

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Electric Current:  Two typesDirect Current (DC): electrons move in one

direction

electric current and electrical energy1.- Electric Current

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Electric Current:  Two typesDirect Current (DC): electrons move in one

direction

electric current and electrical energy

Batteries create a direct current because the electrons always flow from the 'negative' side to the 'positive' side.

1.- Electric Current

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Electric Current:  Two typesDirect Current (DC): electrons move in one

directionAlternating Current (AC): pushes the electrons

back and forth, changing the direction of the flow several times per second.

electric current and electrical energy1.- Electric Current

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Electric Current:  Two typesDirect Current (DC): electrons move in one

directionAlternating Current (AC): pushes the electrons

back and forth, changing the direction of the flow several times per second.

electric current and electrical energy1.- Electric Current

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Electric Current:  Two typesDirect Current (DC): electrons move in one

directionAlternating Current (AC): pushes the electrons

back and forth, changing the direction of the flow several times per second.

electric current and electrical energy

You've probably never noticed the

lights in your house actually flicker as

the current changes direction

because it happens too fast for our

eyes to detect!!!

1.- Electric Current

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Why do we need two types of current, and which one is better?

electric current and electrical energy1.- Electric Current

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Why do we need two types of current, and which one is better?

electric current and electrical energy

AC

1.- Electric Current

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Why do we need two types of current, and which one is better?

electric current and electrical energy

DC

1.- Electric Current

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2.- Voltage

Voltage:  Potential energy between two points.

electric current and electrical energy

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Voltage:  Potential energy between two points.

electric current and electrical energy

Voltage pushes electrons through a circuit.

2.- Voltage

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Voltage:  Potential energy between two points.

electric current and electrical energy

If you rode your bike to the top of the, the higher you move up, the more potential energy the bike will contain.

2.- Voltage

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Voltage:  Potential energy between two points.

electric current and electrical energy

In a battery, the higher differences of charges you have, the more potential energy the battery will contain.

2.- Voltage

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2.- Voltage

Electric Current:  electrons at a higher voltage will light a light bulb more brightly or spin a motor faster than will electrons at a lower voltage.

electric current and electrical energy

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Resistance:  the opposition presented to the current by a material or device (Ohms, Ω)

electric current and electrical energy3.- Resistance

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Resistance :  Is affected by many factors:

electric current and electrical energy3.- Resistance

MaterialThickness Length Tª

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Resistance :  Is affected by many factors:

electric current and electrical energy3.- Resistance

Any change that causes the electrons to have more

collisions with the atoms will increase the resistance of the

object.

MaterialThickness Length Tª

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Generating electrical energy: cells

electric current and electrical energy

Electrochemical cell is something that changes chemical energy to electrical energy.

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Generating electrical energy: cells

electric current and electrical energy

Electrochemistry converts chemically stored energy directly into electrical work: no moving parts, no steam engines, turbines etc.

Electrochemical cell is something that changes chemical energy to electrical energy.

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Generating electrical energy: cells

electric current and electrical energy

Parts of the cell: It contains two compartments, each with an electrode submerged in an electrolyte.

• Electrode: a conductor that connects to a nonmetallic part of a circuit (electrolyte). One positive (cathode) and one negative (anode).

• Electrolyte: fluid that conducts electricity.

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Generating electrical energy: cells

electric current and electrical energy

Anode: electrode at which electrons leave the cell and oxidation occursCathode: electrode at which electrons enter the cell and reduction occurs.

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Generating electrical energy: cells

electric current and electrical energy

Anode: electrode at which electrons leave the cell and oxidation occursCathode: electrode at which electrons enter the cell and reduction occurs.

Reduction: occurs when an element gains electrons: (Cu2+(aq) + 2 e- è Cuo(s))Oxidation occurs when an element loses electron: (Zno(s) - 2 e- è Zn2+(aq))

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Resistance :  Is affected by many factors:

electrical calculations

3.- Resistance

Any change that causes the electrons to have more

collisions with the atoms will increase the resistance of the

object.

MaterialThickness Length Tª

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Generating electrical energy: cells

electric current and electrical energy