Basic mechanical engineering

Basic Mechanical Engineering

Element or Kinematic Link:

                              Each part of machine which is move relative to other part of the machine is called Element or kinematic link or simple link. A link may consists of machine can made of several rigid parts which have no relative motion 

Important things for Link:

1. A link should be a resistive body.
2. A link should have relative motion.

Types of link

There are three types of Link these are:.............................

• Rigid link:

                  A rigid link is that which does not undergo any deformation when it transform the motion in short rigid body does not exist................. hard roads and crack are the example of
  the rigid body
  

  Flexible link:

                  A flexible link is that which partly deformed when the relative motion is transmit.................... for example belt ropes and chain are the example of the flexible link
  

  Fluid link :

                       A fluid link is one which completely deformed by fluid in pipes in this motion is transfer by the pressure and compression .. For example jacks hydrolic breaks are the example of the fluid link.
  
  

  What is a Structure?

                       It is the assemblage of the unknown  number of resistive body
                       it have no relative motion between the parts of structure
  For example: railway line pull etc.

  What is a machine?

  It is the combination of known number of links which have 
  relative motion between them in a machine energy is transfer in to
  useful work

  Difference between Structure and machine

  1. In machine each link has relative motion between them while the member of the structure have no relative motion between them.
  2. In machine energy can be transfer into useful work and in structure no energy can transfer into useful work.
  3. the link may transfer both work and motion between them and the members of the structure can transfer only force. 
  
  

 

Transistor Basics

 

Transistor Basics

what is Transistor?

Transistor is a three semiconductor pin device it is invented by three scientists at the bell laboratories  in 1947. it is made by three layers of doped semiconductors and it constant three terminals 

 Before 1947 we used vacuum tube instead of transistor therefore the electronic devices had large size

for example : first computer in this world is very large because in it Big vacuum tubes are use instead of transistor and a large Equipments and energy was required to maintain these tubes...................

Types of Transistors :

There are basically two types of transistor these are:

1. PNP transistor
2. NPN transistor

PNP transistor

A pnp transistor is a transistor in which n type material is sandwich between two p type semiconductor materials In PNP transistor IE current is emitting from the emitter terminal.

NPN transistor

 A npn transistor is a transistor in which p type material is sandwich between two n type semiconductor materials. In NPN transistor IE current is Entering in the emitter terminal.

mostly npn transistors is used in Electronic Devices

Parts of Transistor :

There Are three important part of  Transistors:

1. Emitter:  Emitter is that comment of the transistor in which max.. current flow       IE>IC>IB
2. Base:      It is the smallest part of transistor and it is lightly doped in this parts IB Current  flow which is very small about in micro amperes
3. collector: Collector is that part of the transistor which is highly doped as compare to emitter and base  

important  Terms used in Transistor :

Important terms used in transistor are:

• Collector current                   IC
• Emitter current                       IE 
• Base current                           IB 
• Beta                                       B   
• Alpha                                     a
• Collector to emitter voltage   VCE
• Base Emitter voltage                       VBE  
• Collector Voltage                   Vcc
•  Emitter voltage                     VEE   

Note:

when diode is operating then emitter base junction is forward base and collector base junction is reversed based

  Configurationof transistor

transistor is used in the circuits in different way for achieve different purposes and these configurations are these:

1. Common base configuration
2. Fixed base configuration
3. Emitter base configuration
4. Voltage divider configuration
5. Common Emitter configuration
6. Feed back configuration

  Important Formulas used in  transistor are:

1.   IE = IB +IC  
2. IE=(B+1)  IB 
3. IE=IC   because IB  approximately zero
4. IC = BIB
5. VCE= Vcc-IBRB -IERE
6.   a=IC/IE

 Used of transistor

Transistor are used for many purposes some are these:

1. It is used as inverter 
2. it is also used for switch 
3. it is used for as amplifier

Thank You.....................................

Please give your Comments.................................

 

 

 

Diodes and Its types

Diodes and Its types

What is Diode?

  " Diode is a semiconductor device it has two terminals . Diode has Unidirectional property it means it flow the current only in one direction And avoid the flow of current in other side"

What is semiconductor?

Semiconductor are those materiel in which energy gap between Conduction band d and valance band is about 5Mev it means it can pass flow of electron only in particular conditions

Doping:

Doping is a process in which we add purines in a pure substance 

Construction of Diode:

 A diode is made by two type of materiel one is p type materiel and other is N type materiel

To make a diode we flow these steps

1. We take a semiconductor materiel of silicon because is cheap and silicon is very effective.
2. we doped one side of the silicon by pentavalent materiel to make n type materiel which have electron as majority carrier impurity is adding in very small quantity eg: one atom of impurity is adding in ten lac atom of silicon.
3. after that we add trivalent impurities in the other part of silicon materiel to make p type which have electrons as majority carrier
4. when p type and n type materiel are are joined then a pn juction is made between them  
5. by these step diode  are made diode are made in industries

 Uses of diode: 

Diode is use for  multi purposes in the electronic industries .

Some of the uses are:

• it is use to allow flow of the current uni direction in the circuit
• it is use in full wave ratification.
• it is used in half wave ratification .
•  it is use in clipper to cut the wave in the circuits

Types of the Diode

 There different types are diodes are available in the markets some of them are:

1. Light emitting diode
2. Avalanche diode
3. Zenger Diode
4. Scohotty diode
5. Laser diode
6. Photo diode
7. Vartactor diode 
8. Rectifier diode
9. Small signal diode
10. Large signal diode
11. Transient voltage suppression diodes
12. Gold Doped diode
13. Super barrier diode
14. Point contact diode
15. Peltier diode
16. Gunn diode
17. crystal diode
18. silicon controlled rectifier
19. Vacuum diode

Thank you.........................................................
Please give your comments........................................................