Introduction to Truss

Consider the crane as shown in the Fig(1) to which a weight 'W' is hung and a string is attached to it as shown in Fig(1) . The normal reaction force which acts normally or more specifically perpendicularly to the point of contact and the gravitational force due to the weight acts upon CF part of crane and the tension of the string acts upon the AD part of the crane in the direction away from the point of suspension of the string and along the string at point D as show shown in the free body diagram of the crane in (a) part of Fig (2) . There are also many internal forces between the joints of the crane which can be considered as external forces when dealt dismembering the crane as shown in the (b ) and (c ) parts of Fig (2) .

Dealing in detail with all the forces , Consider (a) part of Fig(2) , the tension in the string GD acts along GD (the direction along the string) and away from D (point of suspension) and the gravitational force vertically downwards of the weight hung at F . The normal reaction force at A in vertical and horizontal directions .
consider part (b ) of Fig (2) , the tension force at D same as before and normal reaction in vertical (Ax) and horizontal (Ay ) directions same as before and additional normal forces at C due to CE part of the crane in vertical and horizontal direction and the normal force at B in the perpendicular direction to the part BE .
Consider the part (c ) of Fig (2), the reaction pairs of the forces acting in the previous case act here on the parts considered in this figure because according to Newton's third law every force acts in action and reaction pairs which for a force on a body , a force of equal magnitude acts in the opposite direction of the previous force .
In this way the forces act upon each parts of a joint or conducted bodies internally which are not considered and which are the main things to provide support to other parts in order to maintain equilibrium as a whole system together .
Keeping these points in mind we define three things namely Trusses , Frames and Machines differentiating each other .
Trusses:These points are fully constrained usually stationary structures designed to support loads and consist exclusively of straight members connected at joints located at the ends of each member . Members of Truss are acted upon by two equal and opposite forces directed along the member and are so two force members .
Frames:These are also fully constrained usually stationary structures designed to support loads . Frames always contain at least one multiforce member ( which are acted upon by three or more forces generally not directed along the member) like the crane as discussed above .
Machines:There are structures containing moving parts designed to transmit and modify forces and always contain at least one multiforce member like the case of Frames .

Note:The forces which are said to be internal may become external forces depending upon the case like when the parts of the system are considered individually as discussed above .

Posted by Unknown 05:04

SEMICONDUCTORS

JUNCTION DIODE: Diode is a device with
two electrodes(di means two and ode means electrode).A p-n junction
diode is made up of semiconductor crystal which has two
terminals.Junction diode is formed when a semiconductor material such
as silicon or germanium is doped in such a way that one side of it
becomes a p-type and the other side as n-type then we obtain a p-n
junction diode.The plane separating is called a junction.
P-N JUNCTION-DEPLETION LAYER AND BARRIER POTENTIAL:
When p-n junction is formed,the free
electrons and the holes which are in higher concentration on n-side
diffuse over to p-side and p-side diffuse over to n-side this way the
electrons and holes combine and become neutral.This results in the
formation of a narrow region on the either side of the junction which
becomes free from mobile charge carriers.This region is called
depletion layer because the mobile charge carriers are depletion from
this region.The n-type material near the junction becomes positively
charged due to immobile donor ions and the p-type material becomes
negatively charged due to immobile acceptor ions.This creates an
electric field near the junction directed from n-region to p-region
and causes a potential barrier Vb.The potential barrier stops further
diffusion of holes and electrons across the junction.And the value of
the potential barrier depends upon the nature of the crystal,its
temperature and the amount of doping. Posted by Unknown 06:35

SEMICONDUCTORS

P-SEMICONDUCTORS:When a trivalent impurity is added to a tetravalent
semiconductor,it is called p-type semiconductor.If a trivalent
impurity like indium is added to germanium the indium atoms occupy
some of the sites at which three electrons form covalent bonds with
the adjacent germanium atoms because indium has three valence
electrons in outer most shell.The fourth covalent bond is incomplete
or empty,it creates an extra hole.By this way excess holes are formed
in this semiconductor, due to thermal energy conduction takes place in
valence band and conductivity of semiconductor increases.In p-type
semiconductor,holes are majority charge carriers and electrons are
minority charge carriers.In these semiconductors,Fermi energy level
will be nearer to the valence band.And the impurity is called acceptor
impurity.Indium,Gallium,Boron and Aluminium are the trivalent or
acceptor impurities which added to semiconductor materials. Posted by Unknown 18:02

SEMICONDUCTORS

N-TYPE SEMICONDUCTORS:
In n-type semiconductor the impurities are added to the intrinsic
semiconductor in small traces.To the semiconductor the pentavalent
elements such as phosphorous(p),arsenic(As) or antimony(sb) have five
electrons in their outer most shells, so these are added to
semiconductor as the impurities. And from this pentavalent element the
four electrons are engaged in covalent bonding to parent atom. Since
these pentavalent elements donate negative charges(electrons) to the
semiconductor they are called as N-type impurities and the
semiconductors doped with pentavalent impurities are called N-type
semiconductors. If
there is high thermal energy and sufficient doped impurity atoms,then
there occurs the breakage of covalent bonds, by this they generate
electron-hole pairs. In N-type semiconductors electrons are majority
carriers and holes are minority carriers. Posted by Unknown 04:53

SEMICONDUCTORS

Semiconductors are the devices which conduct electricity when an
electric field is applied and semiconductors can conduct electricity
only when the temperature is greater than 0 k.
INTRINSIC SEMICONDUCTOR:Intrinsic semiconductors are the charge
carriers that means electrons in the conduction band and holes in the
valence band.And the semiconductors in their pure form are called as
intrinsic semiconductors.With increase in the thermal energy covalent
bonds are broken and electron-hole pairs are created in the
semiconductors. Ex:silicon and germanium.
EXTRINSIC SEMICONDUCTORS:Extrinsic semiconductor are formed by
adding tritalent or pentatalent impurities to a pure semiconductor or
to intrinsic semiconductors by adding this conductivity increases.And
the process of adding impurities to semiconductors is called 'DOPING'.
Extrinsic semiconductors are of two types:
1.N-type semiconductors 2.P-type
semiconductors Posted by Unknown 03:45

DEFINATIONS

CURRENT:Current is defined as the rate of flow of charge through any
cross section of a conductor. If a net charge
'q' passes through any cross section of the conductor in time 't',then
the average current 'i' is given by Average current i=q/t
Its units are coulomb/second. S.I units are called
ampere(A). RESISTANCE:Resistance is the ratio of the potential
difference 'V' across the conductor to the current 'i' flowing through
the conductor.
Resistance (R)=V/i S.I units of resistance is ohm.
And resistance depends upon its dimensions such as length and
area of cross section and also the temperature.
CONDUCTANCE:Conductance is defined as the reciprocal of
the resistance of a conductor.The conductance of a conductor is the
ratio of current 'i' to the voltage 'V'.
Conductance (G)=i/V S.I
unit of G is ohm inverse or siemens(S). Posted by Unknown 19:21

TYPES OF ELECTRON EMISSION

3.Photo-electric emission:when the surface of certain metals are
exposed to a beam of light,electrons are ejected out of the metal by
the light photons incident on the metal surface.Such an electron
emission is known as photo-electric emission and mostly used in
photo-electric cell.The greater the intensity of light beam falling on
the metal surface,the greater is photo-electric emission.
4.Secondary emission:When a beam of high velocity
electrons strike a metal surface,the free electrons are ejected out of
the metal.This process is known as secondary emission. Posted by Unknown 17:48

TYPES OF ELECTRON EMISSION

The four basic methods of obtaining electron emission
from the surface of a metal depends on the sources such as heat
energy,energy stored in due field,light energy and kinetic energy of
the electric charges bombarding the metal surface.And the four types
of emissions are: 1.Thermionic emission: When a metal is
heated to sufficient temperature,enough thermal energy is imparted to
electrons to enable them to escape from the metal surface.If the
temperature increases electron emission also increases.This method is
known as thermionic emission. 2.Field
emission:When the potential difference between two electrodes is
extremely high,electrons are emitted from the negative electrode,even
at ordinary temperatures.
This process of electron emission is known as field emission.Field
emission does not depend on the temperature of the surface but it is
on the potential difference. Posted by Unknown 17:37

ELECTRON EMISSION FROM METALS

Electron emission is the process by which the free electrons escape
from the surface of a substance.Metals are used for electron emission
because a metal is made up of atoms bound in crystal lattices,of
electrons bound to the atoms,and of many free electrons which are not
bound to any particular location in the metal. The free electrons are
always in motion and travel more or less freely throughout the body of
the metal.However,these electrons are free only to the extent that
they may transfer from one atom to another within the metal but they
cannot leave the metal surface.If the kinetic energy of a electron is
increased by increasing the external energy then the electron will
cross over the surface carrier to escape from the metal.This amount of
kinetic energy required at absolute zero temperature is known as work
function of that metal.It is denoted by Ew and expressed in
electron-volt(eV).One eV is the amount me energy acquired by an fleas
when is is accelerated through a potential difference of one volt. Posted by Unknown 13:14

SEMICONDUCTOR MATERIALS

Here we are going to describe about the materials used as
semiconductors.All semiconductors have crystalline structure.The most
commonly used semiconductor materials are germanium,silicon, and
gallium arsenide have practical applications in electronics.But most
frequently used semiconductors are germanium and silicon because the
energy required to break their covalent bonds and release an free
electron from their valence bands is lesser than that required for
gallium arsenide.The energy required for releasing an electron from
the valence band is 0.66eV for germanium,1.08eV for silicon and 1.58eV
for gallium arsenide. Germanium can
be purified relatively well and crystallised easily.Germanium is an
earth element and it is obtained from the ash of the certain coals or
from the flue dust of the zinc smelters.The recovered germanium is in
the form of germanium dioxide powder which is then reduced to pure
germanium.Germanium diodes are used as infrared detectors in
fibre-optic communication system because of narrower energy gap.
Silicon is an element found in most
of the common rocks.Sand is silicon dioxide which is then reduced to
100% pure silicon.Silicon dioxide is a natural insulator which is
useful in the fabrication of semiconductor devices and integrated
circuits.Silicon is largely preferred to germanium because of its
large gap energy,which produces improved device properties at high
temperatures. Silicon is a better thermal conductor and is required to
remove unavoidable heat developed in the device.
Gallium arsenide has higher electron mobility,which
leads to faster switching capabilities.It has high temperature
operating capabilities because of its larger energy gap. Posted by Unknown 09:10

ENERGY-BANDS IN MATERIALS

-Semiconductors:A semiconductor has conductivity much greater than
that of an insulator but much smaller than that of a metal.At low
temperatures the valence band remains full ,the conduction band is
empty and these materials are insulators at low temperatures.The
conductivity of these materials increases with increase in temperature
and hence these are called as intrinsic semiconductors.As the
temperature is increased some me the electrons in the valence band
acquire thermal energy greater than the energy gap and move to
conduction band.Therefore now these electrons are free to move about
under the influence of even a small applied field.These electrons are
called as conduction electrons.The practically used semiconductors are
germanium and silicon. Posted by Unknown 18:49

ENERGY-BANDS IN MATERIALS

ENERGY-BAND AND CONDUCTION IN INSULATORS,SEMI CONDUCTORS AND METALS
-Insulators
-Metals
-Semiconductors
*Insulator:An insulator is a material having negligible
conductivity.Mainly the forbidden energy gap is more in insulators.If
additional energy is applied to the electron in the upper level of
valence band, then the electron crosses the forbidden energy gap and
enters the conduction band.But energy provided will be much smaller
than the forbidden energy so these are called as insulators.The number
of free electrons in an insulators is very small.
*Metals:Metal is a good conductor of electricity due to the electron
flow and metal has overlapping of valence and conduction bands.The
band occupied by the valence electrons may not be completely filled
and that there are no forbidden levels at higher energies.Depending
upon the metals, sometimes the electrons move freely in the metal.when
we apply the electrical field then these electrons get additional
energy and move to higher energy within conduction band.Hence the
additional energy required for transfer of electrons from valence band
to conduction band is extremely small , so conductivity is
excellent.Example of metal is copper metal. Posted by Unknown 18:39

PENTIUM-4 MICRO PROCESSOR

PENTIUM-4 micro processor was introduced by intel on
november 20,2000.And in pentium-4,it was lined of single-core desktop
and laptop central processing units.Pentium-4 has the 55,000,000
transistors in it.And it contains 32-bit X86 instruction set of the
pentium-4 microprocessors.But later the 32-bit X6 instruction set was
extended by the 64-bit X86-64 set.
And mainly this pentium-4 CPU's introduced the SSE2 and in the
prescott-based pentium-4s.By using this SSE2 and SSE3 instruction sets
to accelerate calculations,transactions,media processing ,
3D-graphics,and games. The pentium-4 has
advanced new version technology than the pentium-3 and pentium-3 xeon
microprocessors. Posted by Unknown 09:59

PENTIUM-3 XEON MICRO PROCESSOR

The pentium-3 Xeon micro processor was developed by
the branded company which is well known as intel.Pentium-3 xeon
processor got introduced in 1998 and it has 28,100,000 transistors in
it. The pentium-3 xeon processors
implements a dynamic execution micro-architecture,a unique combination
of multiple branch prediction , data flow and also speculative
execution.The pentium-3 xeon processor at 600MHz+ is available in a
256k cache size. The
pentium-3 xeon got improved by the generation of 32-bit
processors.Here they used the SINGLE INSTRUCTION MULTIPLE DATA (SIMD)
which performs the 3D graphics too.The pentium-3 xeon processor at
600MHz+ system bus operates using GTL+ signalling levels with a new
type of buffer utilizing active negation and multiple
terminations.This new bus logic is called ASSISTED GUNNING TRANSISTOR
LOGIC--AGTL+. And the next
generation of xeon processors was produced using 0.18 micro
technology.All xeon micro processors with 133MHz FSB(Front side bus)
were in effect pentium-3 coppermine processors in xeon package.Like
desktop pentium-3 CPU's , they had 256KB level 2 cache integrated on
the processor core and didn't support quad-processing.Later on intel
releasede the new version processor which were more advanced than
these. Posted by Unknown 08:20

PENTIUM-2 MICRO PROCESSOR

PENTIUM-2 brand refers to intel's sixth generation
micrarchitecture("P6") and X86-compatible microprocessors which were
introduced on may 7,1997.Pentium-2 processor contains 7.5million
transistors and the pentium-2 featured an improved version of the
first P6-generation core of the pentium Pro which contains 5.5 million
transistors. The pentium-2
350MHz/400MHz/450MHz processor is the next in the pentium-2 processor
intel processor.The pentium-2 processor like the pentium
pro,processor,implement a flow analysis and speculative execution.The
pentium-2 processor also executes MMX technology instructions for
enhanced media and communication performance.The pentium-2 processor
utilizes multiple low power states such as Auto HALT,stop-grant,sleep,
and deep sleep to conserve power during idle times.
In pentium-2 the memory is cacheable for up to GGB
of addressable memory space.
The pentium 2 processor system bus uses a varient of GTL
signal technology called AGTL+ signal technology.

Manufacturer-Intel
Max.cpu clock rate-233MHz
to 450 MHz
FSB speeds-66MHz to 100MHz Minimum
feature size-0.35micro meters to 0.25micro meters
Instruction set-P6
cores-1
socket(s)-slot1,MMC1,MMC2,MINI-CARTRIDGE Posted by Unknown 05:12

PENTIUM-2 MICRO PROCESSOR

PENTIUM-2 brand refers to intel's sixth generation
micrarchitecture("P6") and X86-compatible microprocessors which were
introduced on may 7,1997.Pentium-2 processor contains 7.5million
transistors and the pentium-2 featured an improved version of the
first P6-generation core of the pentium Pro which contains 5.5 million
transistors. The pentium-2
350MHz/400MHz/450MHz processor is the next in the pentium-2 processor
intel processor.The pentium-2 processor like the pentium
pro,processor,implement a flow analysis and speculative execution.The
pentium-2 processor also executes MMX technology instructions for
enhanced media and communication performance.The pentium-2 processor
utilizes multiple low power states such as Auto HALT,stop-grant,sleep,
and deep sleep to conserve power during idle times.
In pentium-2 the memory is cacheable for up to GGB
of addressable memory space.
The pentium 2 processor system bus uses a varient of GTL
signal technology called AGTL+ signal technology.

Manufacturer-Intel
Max.cpu clock rate-233MHz
to 450 MHz
FSB speeds-66MHz to 100MHz Minimum
feature size-0.35micro meters to 0.25micro meters
Instruction set-P6
cores-1
socket(s)-slot1,MMC1,MMC2,MINI-CARTRIDGE Posted by Unknown 05:10

CELERON MICRO PROCESSOR

Intel corporation had made the celeron and it is a brand
name.It is used in different number of X86 computers micro processor
models. Celeron processors
can run all 1A-32 computer programs,but their performance is often
lower when compared to similar CPU's with higher priced intel cpu
brands.But celeron has less cache memory(cache is used in cpu,which is
a smaller,faster memory which stores copies of the data from the most
frequently used main memory locations).
CELERON got introduced in April 1998,the first celeron branded cpu was
based on the Pentium-2 branded core. Subsequent celeron branded cpu's
were based on the Pentium-3,Pentium-4,Pentium M,and Intel core branded
processors.According to the latest celeron design is based on the
second generation are i3/i5/i7 series.This design features contains
independent processing cores but with only 66% as much cache memory as
the core is offering. The family
of celeron processor are
covington,mendocino,coppermine,tualatin,willamette,Northwood,conroe-L.And
recently released one was Jasper Forest which are used for desktops. Posted by Unknown 08:18

DIFFERENT KINDS OF MICRO PROCESSORS

As we know about the intel micro processor in the same
way there are many kinds of micro processors.The list of the
processors are given below:
1.CELERON is a micro processor which consists of 7,500,000 transistors
and speed of cpu is 1.06GHz-2GHz. 2.PENTIUM-2
consists of 7,500,000 transistors and with the cpu speed of
233MHz-450MHz. 3.PENTIUM3 consists of 9,500,000
transistors and cpu speed is of 450MHz-1GHz.
4.PENTIUM-3-XEON consists of 28,100,000 transistors and
500MHz-1GHz cpu speed. 5.PENTIUM-4
consists of 55,000,000 transistors and cpu speed is of 1.4GHz-3.4GHz
6.K6-2 which consists of 9,300,000
transistors and cpu speed is of 500-550MHz
7. K6-3 which consists of 21,300,000 transistors and speed of
cpu is 400-450MHz 8.ATHLON(k7) consists of
22,000,000 transistors and with 850-1.2MHz cpu speed
9.ATHLON XP which consists of 37,500,000 transistors and with the cpu
speed of 1.67MHz 10.DURON with 700MHz-800MHz
11.POWER PC G3 which has 6,500,000 transistors and speed of cpu is
233-333MHz 12.POWER-PC-G4 which has 10,500,000
transistors and speed of cpu is 400-800MHz
13.ATHLON-64 has 105,900,000 and 800MHz 14.G5 has 58,000,000
transistors and speed of cpu is 2.5GHz. Posted by Unknown 12:26

INTEL 4004:

        The intel 4004 is a micro processor which was developed by Tedd hoff and the intel company.He used the new silicon-gated technology might make a single-chip CPU.

         And this micro processor consists of 3 by 4 millimeters which are inter connected through extremely fine wires to store and manipulate data.So by this a micro processor can perform a wide variety of functions.Later on many processors had been developed in the modified versions.

Posted by Unknown 10:29

MICRO PROCESSOR

            MICRO PROCESSOR is a silicon chip that contains central processing unit.Micro processor controls every action in a computer or in a electronic device.It is a multipurpose, programmable device that accepts digital data as input and processes it according to instructions stored in its memory and provides results as output.
            Micro processors also controls the logic of almost all digital devices, from clock radios to fuel-injection systems for the automobiles.General purposes of micro processors are in personal computers which are used for computation,text editing,multimedia display and communication over internet.And many more micro processors are a part of embedded systems providing digital control of a object from appliances of automobiles to cellular phones.

             Micro processors has replaced the integrated circuits,huge transistors and transformed as a modern technology unit.The first developed micro processor was 'INTEL 4004' in early 1970's and were used for electronic calculators,using binary-coded decimal arithmetic on 4-bit word.There are 4-bit and 8-bit micro processors such as terminals,printers,various kinds of automation etc.And then came the 16-bit micro processor for more advance use in that period itself which runs at 25MHz.Presently we are also using the 32 bit micro processor which runs at 50MHz.nowadays in every electronic device the micro processors are emerged which doesn't occupies much space.

Posted by Unknown 07:54

ELECTRONICS

               Electronics is a major stream of engineering and the most important one in our present technical world.

               Electronics deals with the electrical circuits that involve active electrical components such as vacuum tubes,transistors,diodes  integrated circuits,and embed systems etc.Mostly electronics is related to the signal processing through which communication is being carried out.The electronic devices in fixed up with the micro processors through which the signal transmission takes place.

               And the other thing in the electronics is the analog electronic appliances such as radio receivers are constructed from combinations of a few circuits.By these circuits the radio signals are transmitted.Not only in one but in many appliances the electronics plays a vital role.Nowadays  electronics has became the most basic thing where everyone are its comforts it could be in mobile phones where the features are developed more advance and user friendly with well designed processors and circuits, and also in the scientific usage which are used in the satellites,space shuttles etc.
 

Posted by Unknown 08:06