Physical Science Research

INTRODUCTION

This is a research compilation about the alternative sources of energy, lasers, ro-

botics, electronic communication, and electronics.

The first section is about the alternative sources of energy or some substitute

sources that can provide energy. Discussed inside are sources like wind power, solar

power, geothermal power, etc.

The next topic is about lasers. Its properties and classifications are tackled. This

research also contains the hazardous effects of lasers in our body.

Robotics is another concern of this paper. Basic explanation of how robotics work

is evaluated. Different parts of simple robots are also written inside.

Electronic communication is another matter of the research. How great is its help

and how did it affect our lives.

Lastly, discussion about electronics is also compiled. Some of the basic electrical

units, terms and definitions are also clarified.

This document will help you to have a wider knowledge about the environment

and the science behind it.

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ALTERNATIVE

SOURCES

OF

ENERGY

2

ALTERNATIVE SOURCES OF ENERGY

Energy is the ability to do work while energy surrounds us in all aspects of life,

the ability to harness it and use it for constructive ends as economically as possible is

the challenge before mankind. Alternative energy refers to energy sources which are

not based on the burning of fossil fuels or the splitting of atoms. The renewed interest in

this field of study comes from the undesirable effects of pollution (as witnessed today)

both from burning fossil fuels and from nuclear waste by-products. Fortunately there are

many means of harnessing energy which have less damaging impacts on our environ-

ment. Here are some possible alternatives:

Wind Power

Wind can be used to do work. The

kinetic energy of the wind can be changed

into other forms of energy, either mechan-

ical energy or electrical energy.

When a boat lifts a sail, it is using

wind energy to push it through the water.

This is one form of work.

Farmers have been using wind en-

ergy for many years to pump water from

wells using windmills like the one on the

right.

Wind is also used to turn large grinding stones to grind wheat or corn, just like a

water wheel is turned by water power.

Today, the wind is also used to make electricity.

Blowing wind spins the blades on a wind turbine – just like a large toy pinwheel.

This device is called a wind turbine and not a windmill. A windmill grinds or mills grain,

or is used to pump water.

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The blades of the turbine are attached to a hub that is mounted on a turning

shaft. The shaft goes through a gear transmission box where the turning speed is in-

creased. The transmission is attached to a high speed shaft which turns a generator

that makes electricity.

If the wind gets too high, the turbine has a brake that will keep the blades from

turning too fast and being damaged.

You can use a single smaller wind turbine to power a home or a school. A small

turbine makes enough energy for a house. In the picture on the left, the children at this

Iowa school are playing beneath a wind turbine that makes enough electricity to power

their entire school.

How wind turbine works?

The Sun heats our atmos-

phere unevenly, so some patches

become warmer than others. These

warm patches of air rise, other air

blows in to replace them - and we

feel a wind blowing. We can use the

energy in the wind by building a tall

tower, with a large propeller on the

top. The wind blows the propeller

round, which turns a generator to produce electricity.

We tend to build many of these towers together, to make a "wind farm" and pro-

duce more electricity. The more towers, the more wind, and the larger the propellers,

the more electricity we can make. It's only worth building wind farms in places that have

strong, steady winds, although boats and caravans increasingly have small wind gener-

ators to help keep their batteries charged.

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The best places for wind farms are in coastal areas, at the tops of rounded hills,

open plains and gaps in mountains - places where the wind is strong and reliable. Some

are offshore. To be worthwhile, you need an average wind speed of around 25 km/h. 

The propellers are large, to extract energy from the largest possible volume of

air. The blades can be angled to "fine" or "coarse" pitch, to cope with varying wind

speeds, and the generator and propeller can turn to face the wind wherever it comes

from. Some designs use vertical turbines, which don't need to be turned to face the

wind.

The towers are tall, to get the propellers as high as possible, up to where the

wind is stronger. This means that the land beneath can still be used for farming.

Advantages

Wind is free, wind farms need no fuel. 

Produces no waste or greenhouse gases. 

The land beneath can usually still be used for farming. 

Wind farms can be tourist attractions. 

A good method of supplying energy to remote areas. 

Disadvantages

The wind is not always predictable - some days have no wind. 

Suitable areas for wind farms are often near the coast, where land is expensive.

Some people feel that covering the landscape with these towers is unsightly. 

Can kill birds - migrating flocks tend to like strong winds.

However, this is rare, and we tend not to build wind farms on migratory routes

anyway.

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Can affect television reception if you live nearby. 

Can be noisy. Wind generators have a reputation for making a constant, low,

"swooshing" noise day and night, which can drive you nuts.

Having said that, as aerodynamic designs have improved modern wind farms are

much quieter. A lot quieter than, say, a fossil fuel power station; and wind farms

tend not to be close to residential areas anyway. The small modern wind genera-

tors used on boats and caravans make hardly any sound at all. 

Solar Power

We have always used the energy of the sun as far back as humans have ex-

isted on this planet. As far back as 5,000 years ago,

people "worshipped" the sun. Ra, the sun-god, who

was considered the first king of Egypt. In

Mesopotamia, the sun-god Shamash was a major

deity and was equated with justice. In Greece there

were two sun deities, Apollo and Helios. The influ-

ence of the sun also appears in other religions –

Zoroastrianism, Mithraism, Roman religion, Hin-

duism, Buddhism, the Druids of England, the Aztecs

of Mexico, the Incas of Peru, and many Native

American tribes.

We know today, that the sun is simply our

nearest star. Without it, life would not exist on our

planet. We use the sun's energy every day in many

different ways.

When we hang laundry outside to dry in the

sun, we are using the sun's heat to do work – drying

our clothes.

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Plants use the sun's light to make food. Animals eat plants for food. And decay-

ing plants hundreds of millions of years ago produced the coal, oil and natural gas

that we use today. So, fossil fuels is actually sunlight stored millions and millions of

years ago.

Indirectly, the sun or other stars are responsible for ALL our energy. Even nu-

clear energy comes from a star because the uranium atoms used in nuclear energy

were created in the fury of a nova – a star exploding.

Let's look at ways in which we can use the sun's energy.

Solar Cells  

They are really called "photovoltaic", "PV" or "photoelectric" cells that convert

light directly into electricity.

In a sunny climate, you can get enough power to run a 100W light bulb from just

one square metre of solar panel.

This was originally developed in

order to provide electricity for satellites,

but these days many of us own calcula-

tors powered by solar cells.

People are increasingly installing

PV panels on their roofs. This costs thou-

sands of pounds, but if you have a south-facing roof it can help with your electricity bills

quite a bit, and the government pays you for any extra energy you produce and feed

back into the National Grid (called the "feed-in tariff").

Solar water heating

Where heat from the sun is used to

heat water in glass panels on your roof.

This means you don't need to use so much

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gas or electricity to heat your water at home. Water is pumped through pipes in the

panel. The pipes are painted black, so they get hotter when the Sun shines on them.

The water is pumped in at the bottom so that convection helps the flow of hot water out

of the top.

Solar Furnaces

Solar furnaces use a huge array of mir-

rors to concentrate the Sun's energy into a small

space and produce very high temperatures.

Advantages

Solar energy is free - it needs no fuel and produces no waste or pollution.

In sunny countries, solar power can be used where there is no easy way to get

electricity to a remote place. 

Handy for low-power uses such as solar powered garden lights and battery

chargers, or for helping your home energy bills. 

Disadvantages

Doesn't work at night. 

Very expensive to build solar power stations, although the cost is coming down

as technology improves. In the meantime, solar cells cost a great deal compared

to the amount of electricity they'll produce in their lifetime.

Can be unreliable unless you're in a very sunny climate.

Geothermal Power

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Geothermal Energy has been around for as long as

the Earth has existed. "Geo" means earth, and "ther-

mal" means heat. So, geothermal means earth-heat.

The centre of the Earth is around 6000 degrees Celsius

- easily hot enough to melt rock. Even a few kilometres

down, the temperature can be over 250 degrees Celsius

if the Earth's crust is thin. In general, the temperature

rises one degree Celsius for every 30 - 50 metres you go

down, but this does vary depending on location

In volcanic areas, molten rock can be very close to the surface. Sometimes we can

use that heat. Geothermal energy

has been used for thousands of years

in some countries for cooking and

heating.

Hot rocks underground heat water

to produce steam. We drill holes

down to the hot region; steam comes

up, is purified and used to drive tur-

bines, which drive electric generators.

There may be natural "groundwater"

in the hot rocks anyway, or we may need to drill more holes and pump water down to

them.

Advantages

Geothermal energy does not produce any pollution, and does not contribute to

the greenhouse effect.

The power stations do not take up much room, so there is not much impact on

the environment.

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No fuel is needed.

Once you've built a geothermal power station, the energy is almost free.

It may need a little energy to run a pump, but this can be taken from the energy

being generated.

Disadvantages

The big problem is that there are not many places where you can build a geo-

thermal power station. You need hot rocks of a suitable type, at a depth where

we can drill down to them. The type of rock above is also important, it must be of

a type that we can easily drill through. 

Sometimes a geothermal site may "run out of steam", perhaps for decades. 

Hazardous gases and minerals may come up from underground, and can be diffi-

cult to safely dispose of.

Hydroelectric Power

When it rains in hills and mountains,

the water becomes streams and rivers that

run down to the ocean. The moving or fall-

ing water can be used to do work. Energy,

you'll remember is the ability to do work so

moving water, which has kinetic energy,

can be used to make electricity.

Today, moving water can also be

used to make electricity.

Hydro means water. Hydro-electric means making electricity from water power.

Hydroelectric power uses the kinetic energy of moving water to make electricity.

Dams can be built to stop the flow of a river. Water behind a dam often forms a reser-

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voir. Dams are also built across larger rivers but no reservoir is made. The river is sim-

ply sent through a hydroelectric power plant or powerhouse.

How a hydro dam works?

The water be-

hind the dam flows

through the intake

and into a pipe called

a penstock. The wa-

ter pushes against

blades in a turbine,

causing them to turn.

The turbine spins a

generator to produce

electricity. The elec-

tricity can then travel over long distance electric lines to your home, to your school, to

factories and businesses.

Hydro power today can be found in the mountainous areas of states where

there are lakes and reservoirs and along rivers.

Advantages

Once the dam is built, the energy is virtually free. 

No waste or pollution produced.

Much more reliable than wind, solar or wave power. 

Water can be stored above the dam ready to cope with peaks in demand.

Hydro-electric power stations can increase to full power very quickly, unlike other

power stations. 

Electricity can be generated constantly.

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Disadvantages

The dams are very expensive to build. However, many dams are also used for

flood control or irrigation, so building costs can be shared. 

Building a large dam will flood a very large area upstream, causing problems for

animals that used to live there. 

Finding a suitable site can be difficult - the impact on residents and the environ-

ment may be unacceptable. 

Water quality and quantity downstream can be affected, which can have an im-

pact on plant life.

Fossil Fuels

There are three major forms of fossil fuels: coal, oil and natural gas. All three

were formed many hundreds of millions of years ago before the time of the dinosaurs –

hence the name fossil fuels. The age they were formed is called the Carboniferous Pe-

riod. It was part of the Paleozoic Era. "Carboniferous" gets its name from carbon, the

basic element in coal and other fossil fuels.

Coal

Coal is a hard, black colored rock-like sub-

stance. It is made up of carbon, hydrogen, oxygen, ni-

trogen and varying amounts of sulphur. There are

three main types of coal – anthracite, bituminous and

lignite. Anthracite coal is the hardest and has more

carbon, which gives it higher energy content. Lignite is

the softest and is low in carbon but high in hydrogen

and oxygen content. Bituminous is in between. Today, the precursor to coal—peat—is

still found in many countries and is also used as an energy source.

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Oil or Petroleum

Oil is another fossil fuel. It was also formed more than 300 million years ago.

Some scientists say that tiny diatoms are the source of oil. Diatoms are sea creatures

the size of a pin head. They do one thing just like plants; they can convert sunlight di-

rectly into stored energy.

In the graphic on the left, as the

diatoms died they fell to the sea floor

(1). Here they were buried under sedi-

ment and other rock (2). The rock

squeezed the diatoms and the energy

in their bodies could not escape. The

carbon eventually turned into oil under

great pressure and heat. As the earth

changed and moved and folded, pock-

ets where oil and natural gas can be

found were formed (3).

Natural Gas

Natural gas is lighter than air. Natural gas is mostly made up of a gas called meth-

ane. Methane is a simple chemical compound that is made up of carbon and hydrogen

atoms. It's chemical formula is CH4 – one atom of carbon along with four atoms hydro-

gen. This gas is highly flammable.

Natural gas is usually found near petroleum underground. It is pumped from below

ground and travels in pipelines to storage areas. The next chapter looks at that pipe-

line system.

Natural gas usually has no odor and you can't see it. Before it is sent to the pipelines

and storage tanks, it is mixed with a chemical that gives a strong odor. The odor

smells almost like rotten eggs. The odor makes it easy to smell if there is a leak.

Ocean Energy

13

The world's ocean may eventually provide us with energy to power our homes

and businesses. Right now, there are very few ocean energy power plants and most are

fairly small. But how can we get energy from the ocean?

Wave Power

Kinetic energy (movement) exists in the moving waves of the ocean. That energy can

be used to power a turbine. In this simple example, to the right, the wave rises into a

chamber. The rising water forces the air out of the chamber. The moving air spins a

turbine which can turn a generator.

When the wave goes down, air flows through the turbine and back into the chamber

through doors that are normally closed.

This is only one type of wave-energy system. Others actually use the up and down

motion of the wave to power a piston that moves up and down inside a cylinder. That

piston can also turn a generator.

Most wave-energy systems are very small. But, they can be used to power a warning

buoy or a small light house.

Tidal Power

Another form of ocean energy is called

tidal energy. When tides comes into the

shore, they can be trapped in reservoirs be-

hind dams. Then when the tide drops, the

water behind the dam can be let out just

like in a regular hydroelectric power plant.

Tidal energy has been used since about

the 11th Century, when small dams were

built along ocean estuaries and small

streams. the tidal water behind these dams

was used to turn water wheels to mill

grains.

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In order for tidal energy to work well, you need large increases in tides. An increase

of at least 16 feet between low tide to high tide is needed. There are only a few places

where this tide change occurs around the earth. Some power plants are already oper-

ating using this idea.

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LASERS

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LASERS

Properties of Laser Light

Laser light is mono-chromatic, meaning that the light energy is concentrated

within a very tight spectral (wavelength) band. Since water, and by extension, tis-

sue interacts with different light wavelengths differently; a specific laser wavelength

is chosen to achieve certain clinical results. For example, if tissue ablation is de-

sired, selecting a laser wavelength that is highly absorbed by water creates the re-

quired ablation effect.

Laser light is also directional and coherent, which means that it can be tar-

geted accurately and with very high intensity. In a clinical environment, laser light is

delivered only where needed thereby minimizing any collateral tissue damage.

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The Laser/Atom Connection

A laser is a device that controls the way that energized atoms release photons.

"Laser" is an acronym for light amplification by stimulated emission of radiation,

which describes very succinctly how a laser works.

Although there are many types of lasers, all have certain essential features. In a

laser, the lasing medium is “pumped” to get the atoms into an excited state. Typically,

very intense flashes of light or electrical discharges pump the lasing medium and create

a large collection of excited-state atoms (atoms with higher-energy electrons). It is nec-

essary to have a large collection of atoms in the excited state for the laser to work effi -

ciently. In general, the atoms are excited to a level that is two or three levels above the

ground state. This increases the degree of population inversion. The population inver-

sion is the number of atoms in the excited state versus the number in ground state.

Once the lasing

medium is pumped, it con-

tains a collection of atoms

with some electrons sitting

in excited levels. The ex-

cited electrons have ener-

gies greater than the more

relaxed electrons. Just as

the electron absorbed some

amount of energy to reach this excited level, it can also release this energy. As the fig-

ure illustrates, the electron can simply relax, and in turn rid itself of some energy.

This emitted energy comes in the form of photons (light energy). The photon emitted

has a very specific wavelength (color) that depends on the state of the electron's energy

when the photon is released. Two identical atoms with electrons in identical states will

release photons with identical wavelengths.

Three-Level Laser

Here's what happens in a real-life, three-level laser.

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Types of Lasers

There are many different types of lasers. The laser medium can be a solid, gas,

liquid or semiconductor. Lasers are commonly designated by the type of lasing material

employed:

Solid-state lasers  have lasing material distributed in a solid matrix (such as the ruby or

neodymium:yttrium-aluminum garnet "Yag" lasers). The neodymium-Yag laser emits in-

frared light at 1,064 nanometers (nm). A nanometer is 1x10-9 meters.

Gas lasers  (helium and helium-neon, HeNe, are the most common gas lasers) have a

primary output of visible red light. CO2 lasers emit energy in the far-infrared, and are

used for cutting hard materials.

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Excimer lasers  (the name is derived from the terms excited and dimers) use reactive

gases, such as chlorine and fluorine, mixed with inert gases such as argon, krypton or

xenon. When electrically stimulated, a pseudo molecule (dimer) is produced. When

lased, the dimer produces light in the ultraviolet range.

Dye lasers  use complex organic dyes, such as rhodamine 6G, in liquid solution or sus-

pension as lasing media. They are tunable over a broad range of wavelengths.

Semiconductor lasers , sometimes called diode lasers, are not solid-state lasers. These

electronic devices are generally very small and use low power. They may be built into

larger arrays, such as the writing source in some laser or CD players.

What's Your Wavelength?

The Electromagnetic Spectrum and Quantum Energy

 The electromagnetic spectrum consists of the complete range of frequencies from radio

waves to gamma rays.  All electromagnetic radiation consists of photons which are indi-

vidual quantum packets of energy.  For example, a household light bulb emits about

1,000,000,000,000,000,000,000 photons of light per second!  In this course we will only

concern ourselves with the portion of the electromagnetic spectrum where lasers oper-

ate - infared, visible, and ultraviolet radiation.

20

Name Wavelength

Ultaviolet 100 nm - 400 nm

Visible 400 nm - 750 nm

Near Infrared 750 nm - 3000 nm

Far Infrared 3000 nm - 1 mm

Here are some typical lasers and their emission wavelengths:

Laser Type  Wavelength (nm) 

Argon fluoride (UV)  193 

Krypton fluoride (UV)  248 

Xenon chloride (UV)  308 

Nitrogen (UV)  337 

Argon (blue)  488 

Argon (green)  514 

Helium neon (green)  543 

Helium neon (red)  633 

Rhodamine 6G dye (tunable)  570-650 

Ruby (CrAlO3) (red)  694 

Nd:Yag (NIR)  1064 

Carbon dioxide (FIR) 

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Laser Classifications

Lasers are classified into four broad areas depending on the potential for caus-

ing biological damage. When you see a laser, it should be labelled with one of these

four class designations:

Class I - These lasers cannot emit laser radiation at

known hazard levels.

Class I.A. - This is a special designation that applies only

to lasers that are "not intended for viewing," such as a su-

permarket laser scanner. The upper power limit of Class

I.A. is 4.0 mW.

Class II - These are low-power visible lasers that emit

above Class I levels but at a radiant power not above 1 mW. The concept is that the hu-

man aversion reaction to bright light will protect a person.

Class IIIA - These are intermediate-power lasers (cw: 1-5 mW), which are hazardous

only for intrabeam viewing. Most pen-like pointing lasers are in this class.

Class IIIB - These are moderate-power lasers.

Class IV - These are high-power lasers (cw: 500 mW, pulsed: 10 J/cm2 or the diffuse

reflection limit), which are hazardous to view under any condition (directly or diffusely

scattered), and are a potential fire hazard and a skin hazard. Significant controls are re-

quired of Class IV laser facilities.

Laser Safety

22

Ocular Hazards

The laser beam is mono-chromatic, directional and coherent which can serve

as a precision clinical tool. These same properties make it a potential hazard to

your eyes. Think of your eye as a special type of tissue. The eye's interaction with

laser energy also depends on the laser's wavelength. The yellow dotted line indi-

cates where the holmium laser (2100 nm) falls in the electromagnetic spectrum.

Holmium laser energy will be absorbed by your cornea. Under prolonged exposure,

aqueous flare, cataracts, or corneal burn may occur.

All procedure room personnel, including the patient, should wear appropriate

laser safety eyewear while the laser is in operation, even if the procedure is being

done endoscopically.

23

Skin Hazards

Direct the distal tip of the fiber only at the surgical target. Laser exposure on unpro-

tected skin may cause severe skin burns.

24

ROBOTICS

25

ROBOTICS

According to the Robot Institute of

America (1979) a robot is:

"A reprogrammable, multifunctional ma-

nipulator designed to move material,

parts, tools, or specialized devices

through various programmed motions for

the performance of a variety of tasks".

A more inspiring definition can be

found in Webster. According to Webster a robot is:

"An automatic device that performs functions normally ascribed to humans or a ma-

chine in the form of a human."

Laws of Robotics by Isaac Asimov

Law Zero: A robot may not injure humanity, or, through inaction, allow humanity to

come to harm.

Law One: A robot may not injure a human being, or, through inaction, allow a human

being to come to harm, unless this would violate a higher order law.

Law Two: A robot must obey orders given it by human beings, except where such or-

ders would conflict with a higher order law.

Law Three: A robot must protect its own existence as long as such protection does

not conflict with a higher order law.

Roboticists develop man-made mechanical devices that can move by themselves,

whose motion must be modelled, planned, sensed, actuated and controlled, and

whose motion behaviour can be influenced by “programming”. Robots are called “intel-

ligent” if they succeed in moving in safe interaction with an unstructured environment,

while autonomously achieving their specified tasks.

This definition implies that a device can only be called a “robot” if it contains a mov-

able mechanism, influenced by sensing, planning, actuation and control components.

It does not imply that a minimum number of these components must be implemented

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in software, or be changeable by the “consumer” who uses the device; for example,

the motion behaviour can have been hard-wired into the device by the manufacturer.

So, the presented definition, as well as the rest of the material in this part of the WE-

Book, covers not just “pure” robotics or only “intelligent” robots, but rather the some-

what broader domain of robotics and automation. This includes “dumb” robots such

as: metal and woodworking machines, “intelligent” washing machines, dish washers

and pool cleaning robots, etc. These examples all have sensing, planning and control,

but often not in individually separated components. For example, the sensing and

planning behaviour of the pool cleaning robot have been integrated into the mechani-

cal design of the device, by the intelligence of the human developer.

Robotics is, to a very large extent, all about system integration, achieving a task by

an actuated mechanical device, via an “intelligent” integration of components, many of

which it shares with other domains, such as systems and control, computer science,

character animation, machine design, computer vision, artificial intelligence, cognitive

science, biomechanics, etc. In addition, the boundaries of robotics cannot be clearly

defined, since also its “core” ideas, concepts and algorithms are being applied in an

ever increasing number of “external” applications, and, vice versa, core technology

from other domains (vision, biology, cognitive science or biomechanics, for example)

are becoming crucial components in more and more modern robotic systems.

This part of the WEBook makes an effort to define what exactly is that above-men-

tioned core material of the robotics domain, and to describe it in a consistent and moti-

vated structure. Nevertheless, this chosen structure is only one of the many possible

“views” that one can want to have on the robotics domain.

In the same vein, the above-mentioned “definition” of robotics is not meant to be de-

finitive or final, and it is only used as a rough framework to structure the various chap-

ters of the WEBook. (A later phase in the WEBook development will allow different

“semantic views” on the WEBook material.)

Components of robotic systems

This figure depicts the components that are part of all robotic systems. The purpose

of this Section is to describe the semantics of the terminology used to classify the

chapters in the WEBook: “sensing”, “planning”, “modelling”, “control”, etc.

27

The real robot is some mechanical device (“mechanism”) that moves around in the

environment, and, in doing so, physically interacts with this environment. This interac-

tion involves the exchange of physical energy, in some form or another. Both the robot

mechanism and the environment can be the “cause” of the physical interaction

through “Actuation”, or experience the “effect” of the interaction, which can be mea-

sured through “Sensing”.

Robotics as an integrated system of control interacting with the physical world.

Sensing and actuation are the physical ports through which the “Controller” of the ro-

bot determines the interaction of its mechanical body with the physical world. As men-

tioned already before, the controller can, in one extreme, consist of software only, but

in the other extreme everything can also be implemented in hardware.

Within the Controller component, several sub-activities are often identified:

Modelling . The input-output relationships of all control components can (but need not)

be derived from information that is stored in a model. This model can have many

forms: analytical formulas, empirical look-up tables, fuzzy rules, neural networks, etc.

The name “model” often gives rise to heated discussions among different research

“schools”, and the WEBook is not interested in taking a stance in this debate: within

the WEBook, “model” is to be understood with its minimal semantics: “any information

that is used to determine or influence the input-output relationships of components in

the Controller.”

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The other components discussed below can all have models inside. A “System

model” can be used to tie multiple components together, but it is clear that not all ro-

bots use a System model. The “Sensing model” and “Actuation model” contain the in-

formation with which to transform raw physical data into task-dependent information

for the controller, and vice versa.

Planning . This is the activity that predicts the outcome of potential actions, and selects

the “best” one. Almost by definition, planning can only be done on the basis of some

sort of model.

Regulation . This component processes the outputs of the sensing and planning com-

ponents, to generate an actuation setpoint. Again, this regulation activity could or

could not rely on some sort of (system) model.

The term “control” is often used instead of “regulation”, but it is impossible to clearly

identify the domains that use one term or the other. The meaning used in the WEBook

will be clear from the context.

Scales in robotic systems

The above-mentioned “components” description of a robotic system is to be comple-

mented by a “scale” description, i.e., the following system scales have a large influ-

ence on the specific content of the planning, sensing, modelling and control compo-

nents at one particular scale, and hence also on the corresponding sections of the

WEBook.

Mechanical scale . The physical volume of the robot determines to a large extent the

limites of what can be done with it. Roughly speaking, a large-scale robot (such as an

autonomous container crane or a space shuttle) has different capabilities and control

problems than a macro robot (such as an industrial robot arm), a desktop robot (such

as those “sumo” robots popular with hobbyists), or milli micro or nano robots. 

Spatial scale. There are large differences between robots that act in 1D, 2D, 3D, or 6D

(three positions and three orientations).

Time scale . There are large differences between robots that must react within hours,

seconds, milliseconds, or microseconds.

29

Power density scale. A robot must be actuated in order to move, but actuators need

space as well as energy, so the ratio between both determines some capabilities of

the robot.

System complexity scale . The complexity of a robot system increases with the num-

ber of interactions between independent sub-systems, and the control components

must adapt to this complexity.

Computational complexity scale . Robot controllers are inevitably running on real-world

computing hardware, so they are constrained by the available number of computa-

tions, the available communication bandwidth, and the available memory storage.

Obviously, these scale parameters never apply completely independently to the same

system. For example, a system that must react at microseconds time scale can not be

of macro mechanical scale or involve a high number of communication interactions

with subsystems.

Background sensitivity

Finally, no description of even scientific material is ever fully objective or context-free,

in the sense that it is very difficult for contributors to the WEBook to “forget” their back-

ground when writing their contribution. In this respect, robotics has, roughly speaking,

two faces: (i) the mathematical and engineering face, which is quite “standardized” in

the sense that a large consensus exists about the tools and theories to use (“systems

theory”), and (ii) the AI face, which is rather poorly standardized, not because of a lack

of interest or research efforts, but because of the inherent complexity of “intelligent be-

haviour.” The terminology and systems-thinking of both backgrounds are significantly

different, hence the WEBook will accomodate sections on the same material but writ-

ten from various perspectives. This is not a “bug”, but a “feature”: having the different

views in the context of the same WEBook can only lead to a better mutual understand-

ing and respect.

Research in engineering robotics follows the bottom-up approach: existing and

working systems are extended and made more versatile. Research in artificial intelli-

gence robotics is top-down: assuming that a set of low-level primitives is available,

how could one apply them in order to increase the “intelligence” of a system. The bor-

der between both approaches shifts continuously, as more and more “intelligence” is

30

cast into algorithmic, system-theoretic form. For example, the response of a robot to

sensor input was considered “intelligent behaviour” in the late seventies and even

early eighties. Hence, it belonged to A.I. Later it was shown that many sensor-based

tasks such as surface following or visual tracking could be formulated as control prob-

lems with algorithmic solutions. From then on, they did not belong to A.I. any more.

Parts of an Industrial Robot

 The controller is the "brain" of the industrial robotic arm and

allows the parts of the robot to operate together. It works as a

computer and allows the robot to also be connected to other

systems. The robotic arm controller runs a set of instructions

written in code called a program. The program is inputted with

a teach pendant. Many of today's industrial robot arms use an

interface that resembles or is built on the Windows operating

systemThe controller is the "brain" of the industrial robotic

arm and allows the parts of the robot to operate together. It

works as a computer and allows the robot to also be con-

nected to other systems. The robotic arm controller runs a set of instructions written in

code called a program. The program is inputted with a teach pendant. Many of to-

day's industrial robot arms use an interface that resembles or is built on the Windows

operating system.

 Industrial robot arms can vary in size and shape. The

industrial robot arm is the part that positions the end ef-

fector. With the robot arm, the shoulder, elbow, and wrist

move and twist to position the end effector in the exact

right spot. Each of these joints gives the robot another

degree of freedom. A simple robot with three degrees of

freedom can move in three ways: up & down, left & right,

and forward & backward. Many industrial robots in facto-

ries today are six axis robots.

31

 The end effector connects to the robot's arm and func-

tions as a hand. This part comes in direct contact with the

material the robot is manipulating. Some variations of an

effector are a gripper, a vacuum pump, magnets, and weld-

ing torches. Some robots are capable of changing end ef-

fectorsand can be programmed for different sets of tasks.

 The drive is the engine or motor that moves the links into

their designated positions. The links are the sections be-

tween the joints. Industrial robot arms generally use one of

the following types of drives: hydraulic, electric, or pneu-

matic. Hydraulic drive systems give a robot great speed

and strength. An electric system provides a robot with less

speed and strength. Pneumatic drive systems are used for

smaller robots that have fewer axes of movement. Drives should be periodically in-

spected for wear and replaced if necessary.

Sensors allow the industrial robotic arm to receive feed-

back about its environment. They can give the robot a

limited sense of sight and sound. The sensor collects in-

formation and sends it electronically to the robot con-

trolled. One use of these sensors is to keep two robots

that work closely together from bumping into each other.

Sensors can also assist end effectors by adjusting for

part variances. Vision sensors allow a pick and place robot to differentiate between

items to choose and items to ignore.

Advantages and Disadvantages

32

Advantages

You can send them to very dangerous places.

You can make them do you're job for you.

They are more accurate than humans, example, no shaking when in a very important

surgery, puts every screw in fabricating a car etc.

Can do jobs 24/7.

Can guard without being tired just keep doing the same thing 24/7.

No need of nutrients.

You can programme them to make them do exactly what you want them to do.

They can not harm you unless they are programmed to.

Can work with out doubts, example, when you think "what do i do now"?

They can lift very heavy things,

Disadvantages

You need to get people trained to fix them if anything wrong happens.

Need a very intelligent crew.

They can ruin peoples lives, example, take their job away from them.

They are very expensive to make.

You need the right materials to make them that could be very rare.

If you make a very amazing robot with amazing quality and it brakes, it might be very

hard to fix.

They can be very hard to programme.

They can reproduce but it could cost money for the materials.

You need highly trained people to make them.

They can not recharge themselves.

33

ELECTRO

COMMUNICATION /

ELECTRONIC

COMMUNICATION

34

ELECTRO COMMUNICATION

Electric fish can use electricity as a communicative device, much as humans use

auditory signals. Using its electric organ, the

fish produces an electric organ discharge

(EOD), which is broadcast through the sur-

rounding water and received by other fish in

the environment. These other fish detect the

signals and process various aspects of the sig-

nal to determine its significance. Fish con-

stantly emit EOD's, and thus are continuously

providing informational cues to their surrounding environment. Electro communicative

signals can express a fish's species, gender, reproductive intent, social status, and even

level of aggression. While some progress has been made to identify and characterize

different signals and their meanings, decoding electrocomminicative "fish speak" is a

difficult process, and much remains to be discovered. Each species of electric fish

varies its EOD differently to communicate different cues.

EOD Variation

Fish EODs vary according to many factors, including signal type, frequency, du-

ration, and structure. Different combinations of these factors produce signals with differ-

ent meanings.

Pulse and Wave: Some fish produce short bursts of communicative electric signal

called "pulses," and oth-

ers produce longer sig-

nals called "waves" also

called "tones" (Hopkins

1972). Pulse discharges

are "brief with respect to

the period between dis-

charges" and have variable frequency (Hopkins 1972). Wave or tone signals have dis-

35

charges nearly equal in length to the period between discharges, and relatively stable

frequency (Hopkins 1972). Individuals of a single species produce either wave signals

or pulse signals, but not both. The Black Ghost Knife fish (Apteronotus albifrons) is a

wave producing fish, while the Elephant Nose fish (Gnathonemus petersii) produces

pulses (von der Emde 1999).

EOD Shape: Fish also produce EODs of different structures or shapes. A signal may

begin with a strong peak and gradually fade, or it may rise slowly to peak at the end of

the signal. EOD shapes vary from species to species, between males and females, or

even with age. They also vary from individual to individual.

Other Factors: Even if a fish keeps the structure of its EOD discharge consistent, it can

vary the frequency, amplitude, or duration of a signal. There are many ways in which

fish electro communicative signals differ.

Examples of Electrocommunication

Instead of trying to give a comprehensive account of EOD variation in makeup

and meaning, I have listed a number of specific examples below to give an indication of

how fish use electrocommunication.

Species: One indication a fish may give of its species is the type of EOD it emits. As

note above, some species produce wave signals, and others produce pulses. However,

as many wave or pulse generating fish may live in a single area, other indicators are

necessary for further distinction. Within wave-type fish, different frequencies can indi-

cate different species. For example, some species in the Moco-moco creek in the Rupu-

nuni District of South America are distinguishable by EOD frequency. Sternopygus

macrurus EOD frequencies range between 50 and 150 hz, Eigenmannia virescens fre-

quencies average 240 to 580 hz, and Apteronotus albifronsfrequencies are even higher-

750-1250 hz (Hopkins 1972).

Gender: Gender information can be conveyed by the frequency of a fish's EOD, though

the way in which frequency is related to gender may vary across species. Brown Ghost

36

Knifefish (Apteronotus leptorynchus),

males typically have higher EOD frequen-

cies than females: 800-1000 hz for males,

600-800 hz for females(Bastian et al.

2001). However, in Sternopygus macru-

rus individuals, the females exhibited

higher frequency signals (120.1 for females, 66.8 for males) (Hopkins 1972). 

Gender information can be indicated by aspects of the EOD other than fre-

quency. Brienomyrus brachyistius triphasic females and males differ in the structure of

their EOD pulse. Males emit longer pulses characterized by an initial peak, a gradual

decrease, and a shallow dip. Females and juveniles have shorter pulses, no apprecia-

ble decrease, and a deeper dip (Hopkins and Bass 1981).

Courtship: Males of the Sternopygus macrurus species exhibit specific patterns of vari-

ation in their usual wave-type EOD to indicate courtship intent. This pattern is generated

by enhancing the normal wave pattern through signal cessation and frequency varia-

tion. S. macrurus males interrupt their normal wave pattern or briefly increase the EOD

frequency to create a unique pattern, and they exhibit this pattern only in courtship situ-

ations (Hopkins 1972). The males of a species of West African pulse-type electric fish

called Brienomyrus brachyistius triphasic also vary EOD frequency in courtship. They

drastically increase their normal EOD pulse briefly to produce high frequency bursts of

electric signal to attract potential mates (Hopkins and Bass 1981).

Aggression: Studies with the Brown Ghost Knifefish Apteronotus leptorynchus have

shown that their aggressive behavior is expressed by varying the duration of their

EODs. Short, low frequency “chirps” (~15-30 ms) indicate aggression, while longer

“rises” or higher frequency chirps seem to show submission (Trifenbach and Zakon

2002).

Size: Fish size seems to be correlated with the magnitude of the EOD: the larger the

fish, the more electrical signal it can produce, and thus the stronger its signal. In male

37

Brown Ghost Knifefish, size and EOD frequency are also positively correlated. The re-

sults for females of the same species are less conclusive. (Trifenbach and Zakon 2002)

A number of fish possess an active electric sense - they can generate electric

fields with an electric organ (EO) and receive electric signals with specialised electrore-

ceptors. Electro genesis has evolved independently in at

least six lineages of teleosts and elasmobranches, which

can be subdivided into strongly and weakly electric fish

according to the power of their electric discharge. The

electric (Electrophorus electricus) is probably the best-

known representative of the strongly electric fish that

produce electric shocks of up to several hundred volts

mainly for stunning prey or predators. Weak electric dis-

charges of no more than a few volts are generated by several hundred species of ma-

rine and freshwater fish, but best studied are two species freshwater lineages that

present remarkable examples of convergence. The African Mormyriformes (which com-

prise the Mormyridae or elephantfish and the Gymnarchidae with Gymnarchus niloti-

cus as the only species) and the South American Gymnotiformes (or Neotropical knife-

fish) are only distantly related and have evolved their strikingly similar mechanisms of

signal generation and recognition completely separately. Both groups use electric sig-

nals for active electro location and sophisticated electro communication. This dual func-

tion could explain why EOs with weak discharges, which have been hypothesised to

represent an intermediate stage in the evolution of more powerful EOs, was retained.

Generation and reception of electric signals

The EOs of electric fish consist of modified muscle or nerve cells called electro-

cytes, the potentials of which are summed and delivered simultaneously to the sur-

rounding water as an electric organ discharge (EOD). Discharge patterns are generated

by a hierarchy of control nuclei in different regions of the brain and can be categorised

into two types: pulse and wave. Pulse-type EODs are brief, often multi-phasic pulses

emitted at irregular intervals, while wave-type EODs are longer lasting, often monopha-

sic (forming a sine wave-like pattern) and delivered constantly within a certain frequency

38

band. EODs show great diversity, due to physiological

differences in, for example, the type, density and distri-

bution of ion channels in electrocyte membranes or the

mode of EO innervation. Complex pulse and wave dis-

charges have evolved in both the mormyriforms and

gymnotiforms and within the latter, pulse-type EODs

have probably arisen independently in several families.

The self-generated electric fields as well as those of other fish are perceived with

sensitive electroreceptors that convert external electrical stimuli into internal neural re-

sponses. They are usually widely distributed over the body surface but more densely

clustered around the head. Mormyriforms and gymnotiforms have independently

evolved tuberous receptors that consist of a jelly-filled canal covered by an epithelial cell

plug and are tuned to the high-frequency components of a species' EOD. Mormyriforms

possess two types of tuberous receptor - so-called Knollenorgans are employed in com-

munication and mormyromasts in electrolocation. In gymnotiforms, one tuberous recep-

tor type is specialised for detecting the amplitude of a stimulus and another for timing,

but both are used for electrolocation as well as communication. Similar computational

algorithms for the sensory processing of temporal cues have evolved several times, for

example at least twice within the mormyriforms. The mechanisms for time coding and

time comparison are furthermore reminiscent of those used by barn owls to process au-

ditory stimuli, as both rely on neural delay lines and coincidence detectors.

Electro location

Electric fish can detect and identify objects in their surroundings by sensing the

minute perturbations these objects make in their self-generated electric field, a process

referred to as active electro location. It allows them to analyse and distinguish the dis-

tance, form and electrical properties of objects and thus to 'see' these objects in condi-

tions where vision is impaired (e.g. in murky waters or at night). Weakly electric fish

usually swim with a stiff body, as this makes it easier for them to register the distortions

of the isopotential lines.

Electro location has parallels with echolocation,

and like the echolocation calls of bats, the EODs of

39

electric fish are shaped by the environment (as the type of microhabitat is likely to affect

the efficiency of different electric signals). Ultra-brief signals, for example, that detect a

wider range of impedances from objects have evolved independently in mormyriforms

and gymnotiforms. In contrast to echolocation, however, electrolocation only works over

short distances, because signal amplitude rapidly decreases with distance. The electric

image falling on the receptors is blurred, and resolution depends on electroreceptor

density. Some weakly electric fish (e.g. Gnathonemus petersii) evidently possess elec-

tric foveae analogous to the auditory fovea of echolocating bats or the fovea of theeye.

Electro communication

Electric communication is well developed (and, of course, convergent) in gymno-

tiforms and mormyriforms. By combining their electro genic and electroceptive capaci-

ties, these fish are able to communicate with electric signals - the EOD of a signaller is

sensed by a receiver at a distance. As EODs are complex and diverse, they can convey

a great deal of information. EOD waveforms are species-specific and have often been

shown to be particularly divergent in sympatric species (e.g. in the genera Campylo-

mormyrus, Marcusenius and Mormyrops). They might act as 'species markers', facilitat-

ing species recognition during mate choice. Thus, the electro sensory system has prob-

ably been a major stimulus (so to speak) in the evolutionary diversification of weakly

electric fish, affecting the formation and maintenance of species boundaries within

rapidly radiating groups. But EOD waveforms do not only differ between species, but of-

ten also between the sexes or age classes; in some species, they are even individually

distinct.

The pattern of discharges is involved in signalling aspects of complex social be-

haviour such as aggression, submission, threat or alarm and might also function

in courtship. Not much is known about the use of electric signals in courtship, but a re-

cent study on the mormyrid Brienomyrus brachyistius has shed some light. Males and

females of this species performed electrical duetting, where they exchanged 'rasps' and

'bursts'. Potential functions of these duets could be to evaluate the quality of or maintain

contact with a potential mate or to indicate mutual interest.

40

A more unusual example of a communicative func-

tion of electric signals involves a piscivorous mormyrid, the

Cornish jack (Mormyrops anguilloides). This electric fish

preys on rock-dwelling cichlids in Lake Malawi and forms

stable predatory associations of 2-10 individuals, reminiscent of the hunting packs ob-

served in socially foraging carnivores and cetaceans. Although no coordinated hunt-

ing tactics were obvious, group members produced synchronised EOD bursts that have

been interpreted as pack cohesion signals.

ELECTRONIC COMMUNICATION

The term electronic communication is defined as passing of information from one

individual to another using computers, fax and phones.

Types of Electronic Communication

1. Email

o Email has had its critics, notably for the brevity of messages and for the rapidity of reply,

which often negates clear thought. But all new things will have critics. Writing to some-

one by conventional mail and waiting for a response takes days or weeks. Waiting

sometimes just a few minutes for a response by email seemed quite magical in the early

days of the internet. Now this is taken for granted. The problem of spam has never been

dealt with satisfactorily, but being able to email photographs on the day they were taken

to a loved one on the other side of the world makes up for some of the negatives.

2. Newsgroups, Chatrooms, Video Conferencing

o Newsgroups and chat rooms began as early types of social media. Newsgroups rely on

people's posting messages to a relevant group, and members of that group can then

comment instantaneously. In recent years, newsgroups have, to a large extent, been re-

placed by slick social-networking sites such as Facebook, MySpace and Twitter. Chat

rooms still have a dubious reputation on the net, because though they can be great

places for friends spread around the globe to meet up, unwelcome visitors will often use

41

them inappropriately. Standalone video conferencing, used for business, has also now

been matched by instant-messaging programs.

3. Social Media and Instant Messaging

o Social media may be seen by many as even more important than email now. Facebook

and MySpace have an email facility and instant messaging, and Twitter has a direct-

message and instant-reply facility. Instant messaging, which is also available from the

likes of Yahoo! and MSN, is becoming increasingly more advanced. Whereas in the

early days of Yahoo! Messenger you could save money on a phone call to someone

overseas, now you can not only talk but look at a live video image of that person at the

same time.

Advantages of Electronic Communication

The following points highlight on the advantages of electronic communication:

1. Speedy transmission:  It requires only few seconds to communicate through elec-

tronic media because it supports quick transmission.

2. Wide coverage: World has become a global village and communication around the

globe requires a second only.                                                                                            

3. Low cost: Electronic communication saves time and money. For example Text sms

is cheaper than traditional letter.

4. Exchange of feedback: Electronic communication allows instant exchange of feed-

back. So communication becomes perfect using electronic media.

5. Managing global operation: Due to advancement of electronic media, business

managers can easily control operation across the globe. Video or tele conferencing e-

mail and mobile communication are helping managers in this regard.

42

Disadvantages of Electronic Communication

Electronic communication is not free from the below limitations:

1. Volume of data: The volume of telecommunication information is increasing in such

a fast rate that business people are unable to absorb it within relevant time limit.

2. Cost of development: Electronic communication requires huge investment for in-

frastructural development. Frequent change in technology also demands for further in-

vestment.                                    

3. Legal status: Data or information, if faxed, may be distorted and will cause zero

value in the eye of law.

4. Undelivered data: Data may not be retrieved due to system error or fault with the

technology . Hence required service will be delayed

5. Dependency: Technology is changing everyday and therefore poor countries face

problem as they cannot afford new or advanced technology. Therefore poor countries

need to be dependent towards developed countries for sharing global network.

43

ELECTRONICS

44

ELECTRONICS

Electronics is the branch of science that deals with the study of flow and control of

electrons (electricity) and the study of their behavior and effects in vacuums, gases, and

semiconductors, and with devices using such electrons. This control of electrons is ac-

complished by devices that resist, carry, select, steer, switch, store, manipulate, and ex-

ploit the electron.

Some of the basic electrical units and definitions are mentioned below:

Passive: Capable of operating without an external power source. Typical passive com-

ponents are resistors, capacitors, inductors and diodes (although the latter are a special

case).

Active: Requiring a source of power to operate.    Includes transistors (all types), inte-

grated circuits (all types), TRIACs, SCRs, LEDs, etc.

DC: Direct Current. The electrons flow in one direction only.  Current flow is from nega-

tive to positive, although it is often more convenient to think of it as from positive to neg-

ative.  This is sometimes referred to as "conventional" current as opposed to electron

flow.

AC: Alternating Current. The electrons flow in both directions in a cyclic manner - first

one way, then the other.  The rate of change of direction determines the frequency,

measured in Hertz (cycles per second).

Frequency: Unit is Hertz, Symbol is Hz, old symbol was cps (cycles per second). A

complete cycle is completed when the AC signal has gone from zero volts to one ex-

treme, back through zero volts to the opposite extreme, and returned to zero.  The ac-

cepted audio range is from 20Hz to 20,000Hz.  The number of times the signal com-

pletes a complete cycle in one second is the frequency.

45

Voltage: Unit is Volts, Symbol is V or U, old symbol was E. Voltage is the "pressure" of

electricity, or "electromotive force" (hence the old term E).  A 9V battery has a voltage of

9V DC, and may be positive or negative depending on the terminal that is used as the

reference.  The mains has a voltage of 220, 240 or 110V depending where you live -

this is AC, and alternates between positive and negative values.  Voltage is also com-

monly measured in millivolts (mV), and 1,000 mV is 1V.  Microvolts (uV) and nanovolts

(nV) are also used.

Current: Unit is Amperes (Amps), Symbol is I . Current is the flow of electricity (elec-

trons).  No current flows between the terminals of a battery or other voltage supply un-

less a load is connected.  The magnitude of the current is determined by the available

voltage, and the resistance (or impedance) of the load and the power source.  Current

can be AC or DC, positive or negative, depending upon the reference.  For electronics,

current may also be measured in mA (milliamps) - 1,000 mA is 1A.  Nanoamps (nA) are

also used in some cases.

Resistance: Unit is Ohms, Symbol is R or Ω. Resistance is a measure of how easily (or

with what difficulty) electrons will flow through the device.  Copper wire has a very low

resistance, so a small voltage will allow a large current to flow.  Likewise, the plastic in-

sulation has a very high resistance, and prevents current from flowing from one wire to

those adjacent.  Resistors have a defined resistance, so the current can be calculated

for any voltage.  Resistance in passive devices is always positive (i.e. > 0)

Capacitance: Unit is Farads, Symbol is C.  Capacitance is a measure of stored

charge.  Unlike a battery, a capacitor stores a charge electrostatically rather than chemi-

cally, and reacts much faster.  A capacitor passes AC, but will not pass DC (at least for

all practical purposes).  The reactance or AC resistance (called impedance) of a capaci-

tor depends on its value and the frequency of the AC signal.  Capacitance is always a

positive value.

Inductance: Unit is Henrys, Symbol is H or L (depending on context). Inductance oc-

curs in any piece of conducting material, but is wound into a coil to be useful.  An induc-

46

tor stores a charge magnetically, and presents a low impedance to DC (theoretically

zero), and a higher impedance to AC dependent on the value of inductance and the fre-

quency.  In this respect it is the electrical opposite of a capacitor.  Inductance is always

a positive value. 

Impedance: Unit is Ohms, Symbol is Ω or Z. Unlike resistance, impedance is a fre-

quency dependent value, and is specified for AC signals.  Impedance is made up of a

combination of resistance, capacitance, and/ or inductance.  In many cases, impedance

and resistance are the same (a resistor for example).  Impedance is most commonly

positive (like resistance), but can be negative with some components or circuit arrange-

ments.

Decibels: Unit is Bel, but because this is large, deci-Bels (1/10th Bel) are used), Sym-

bol is dB. Decibels are used in audio because they are a logarithmic measure of volt-

age, current or power, and correspond well to the response of the ear.  A 3dB change is

half or double the power (0.707 or 1.414 times voltage or current respectively).

Electronic components are basic electronic element or electronic parts usually pack-

aged in a discrete form with two or more connecting leads or metallic pads. 

Electronic Components are intended to be connected together, usually by soldering to a

printed circuit board (PCB), to create an electronic circuit with a particular function (for

example an amplifier, radio receiver, oscillator, wireless). 

Some of the main Electronic Components are: resistor, capacitor, transistor, diode, op-

erational amplifier, resistor array, logic gate etc.

Electronic Components are of 2 types:  

Passive electronic components are those that do not have gain or  directionality.

They are also called Electrical elements or electrical components. e.g. resistors, capaci-

tors, diodes, Inductors.

47

Junction field effect tran-sistor

Metal oxide field effect transistor (MOSFET) Bipolar Transistor Operational amplifier

Logic gates

Active components are those that have gain or directionality. e.g. transistors, inte-

grated circuits or ICs, logic gates.

ResistorCapacitor

Diode 

Inductor 

Here are some of the Electronic Components and their functions in electronics and elec-

trical:

1. Terminals and Connectors: Components to make electrical connection.

2. Resistors: Components used to resist current.

3. Switches: Components that may be made to either conduct (closed) or not (open).

4. Capacitors: Components that store electrical charge in an electrical field.

5. Magnetic or Inductive Components: These are Electrical components that use

magnetism.

6. Network Components: Components that use more than 1 type of Passive Compo-

nent.

7. Piezoelectric devices, crystals, resonators: Passive components that use piezo-

electric effect.

48

8. Semiconductors: Electronic control components with no moving parts.

9. Diodes: Components that conduct electricity in only one direction.

10. Transistors: A semiconductor device capable of amplification.

11. Integrated Circuits or ICs: A microelectronic computer circuit incorporated into a

chip or semiconductor; a whole system rather than a single component.

49

REFERENCE

http://www.energyquest.ca.gov/story/chapter01.html

http://www.darvill.clara.net/altenerg/index.htm

http://www.convergentlaser.com/laser_safety.php

http://science.howstuffworks.com/laser.htm

http://www.electronicsteacher.com/robotics/what-is-robotics.php

http://www.robots.com/faq/show/what-are-the-main-parts-of-an-industrial-robot

http://14wo.qataracademy.wikispaces.net/Advantages+and+disadvantages+of+robotics

http://www.mapoflife.org/topics/topic_578_Electrolocation-and-electrocommunication-in-

weakly-electric-fish/

http://www.bio.davidson.edu/dorcas/animalphysiology/websites/2003/Wilson/

Communication.htm

http://www.electronicsandyou.com/index.html

http://www.ask.com/question/what-is-electronic-communication

http://www.ehow.com/list_7612671_6-types-electronic-communication.html

http://docommunication.weebly.com/1/post/2013/03/advantages-anddisadvantagesof-

electronic-communication.html

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