EC1

Electricity

A form of energy resulting from the existence of charged particles (such as electrons or protons), either statically as an accumulation of charge or dynamically as a current.

Copper

most commonly used metal in the electrical/electronics industry.

1. Silver 2. Copper 3. Gold 4. Aluminum

good conductors of electricity from 1st to 4th

Electron

smallest particle that exhibits electric charge

Electrical charge

is an electrical property of matter that exists because of an excess or deficiency of electrons.

net negative electrical charge.

When an excess of electrons exists in a material, there is a ____

net positive electrical charge.

When a deficiency of electrons exists, there is a ____

Static Electricity

• the presence of a net positive or negative charge in a material.

• When you rub a balloon on your pullover, you create static electricity that makes it stick. The rubbing shifts electrons from your pullover (which becomes positively charged) to the latex rubber in the balloon (which becomes negatively charged). The opposite charges make the two things stick.

Lightning

Heavier, negatively charged particles sink to the bottom of the cloud. When the positive and negative charges grow large enough, a giant spark - lightning - occurs between the two charges within the cloud. This is like a static electricity sparks you see, but much bigger.

Lightning Arrester

kinakabit sa building para doon tumama ung lightning

Thomas Edison

founder of DC Power system

Direct Current

Practical Incandescent  Light Bulb (1879) 

Phonograph (1877)

Motion Picture Camera & Viewer (Kinetograph & Kinetoscope, 1891) 

Nikola Tesla

founder of AC power system

Alternating Current

AC induction motor

Tesla Coil (1891)

Radio and Wireless Technology

Teleautomaton (First Remote Control, 1898) 

1. Armature

2. Slip rings

3. Field Magnet

4. Brushes

AC generator parts

1. Armature

2. Split rings

3. Field Magnet

4. Brushes

DC generator parts

Commutator

• Ends of armature coils terminated at commutator segments

• made of copper segments insulated by mica

• collect current from armature conductors

• the emf generated is always alternating from the armature conductors but this helps convert this into a direct one

AC Voltage

an ______ is one that continually change in magnitude and periodically reverse in polarity. It came from the theory of electromagnetic induction “whenever the flux linking a coil changes and emf is induced”

Faraday’s law of Electromagnetic Induction

Whenever a conductor cuts the flux of a magnetic field, an emf is produced in the conductor. If the two ends of the conductor are connected to an outside circuit, the induced emf causes current to flow in the circuit.

Voltage

• symbolized by V, is defined as energy or work per unit charge.

• V= W(joules/J) / Q (coulombs/C)

• provides energy to electrons, allowing them to move through a circuit.

Current

• This movement of electrons is the ______, which results in work being done in an electrical circuit.

• It is the rate of flow of charge.

• ________in a conductive material is determined by the number of electrons (amount of charge) that flow pass a point in a unit of time.

• I = Q/t

VOLTAGE SOURCE

it provides electrical energy or electromotive force ( emf ), more commonly known as voltage.

1. chemical energy

2. light energy

3. magnetic energy combined with mechanical motion.

Voltage is produced by means of ____, ____, _______

Dynamic Electricity

Dynamic electricity is the flow of electric charges through a conductor; in other words, an electric current.

Sources of electricity

Friction, Chemical action, Light action, Heat action, Pressure, Mechanical action

Ideal Current Source

an ideal voltage source can provide a constant voltage for any load. An ideal current source can provide a constant current in any load. Just as in the case of a voltage source, the ideal current source does not exist but can be approximated in practice.

Resistance

The property of a material to restrict or oppose the flow of electrons is

Resistor

A component that is specifically designed to have a certain amount of resistance is called a

1. limit current in a circuit

2. to divide voltage

3. and, in certain cases, to generate heat.

The principal applications of resistors are to 1. 2. 3.

1. fixed

2. variable

Although resistors come in many shapes and sizes, they can all be placed in one of two main categories: 1. or 2.

Fixed resistors

are available with a large selection of resistance values that are set during manufacturing and cannot be changed easily.

Variable resistors

designed so that their resistance values can be changed easily.

basic uses are to divide voltage and control current.

potentiometer

variable resistor used to divide voltage

rheostat

variable resistor used to control current

1. Material

2. Length

3. Cross-sectional area

4. temperature

Resistance of any material is due primarily to the following factors:

Inferred Absolute temperature

For good conductors, increase in temperature results to increase in resistance level. For copper, (and most other metallic conductors) the resistance almost increases linearly.

Temperature coefficient of Resistance

____________ is the rise in the resistance of a material per degree rise in temperature to the original resistance.

Power

rate of doing work

rate at which energy is used

Resistor Power Rating

maximum amount of power that a resistor can dissipate without being damaged by excessive heat buildup

Energy

ability to do work W = Pt