electromagnatic theory

transistor as a switch

moslty transistor are used in following application

transistor as a switch

transistor work as a switch
if we see the picture we have three region there
cutoff
active
saturation

cutoff
in cut off region
The input and Base are grounded (0v)
Base-Emitter voltage VBE < 0.7V
Base-Emitter junction is reverse biased
Base-Collector junction is reverse biased

Transistor is "fully-OFF" (Cutoff region)
No Collector current flows ( IC = 0 )
VOUT = VCE = VCC = "1"
Transistor operates as an "open switch"
Saturation
•The input and Base are connected to VCC
•Base-Emitter voltage VBE > 0.7V
•Base-Emitter junction is forward biased
•Base-Collector junction is forward biased
•Transistor is "fully-ON" (saturation region)
•Max Collector current flows (IC = Vcc/RL)
•VCE = 0 (ideal saturation)
•VOUT = VCE = "0"
•Transistor operates as a "closed switch"

Electricity
CHARGE
Before introduction of electricity I want to introduce charge so charge is the property of any matter particle responsible for attracting or repelling other matter particle.

Unit of charge is coulomb which consist of 6.24 ´ 1018 unit of electrical charge

this is structure of a atom here proton and electrons are unit of charge.





Electron are negetively charged particle
while proton are positevily charged particle

one electron has - 1.6´ 10-19 coulomb of charge



ELECTRICITY
DEFINATION
a physical phenomenon associated with stationary or moving electrons and protons is electricity

energy made available by the flow of electric charge through a conductor .

In simple word we can say energy generated by flow of charge known as electricity .now electricity is prime source of energy


here are some pictures related to electricity transmission and use of electricity




CURRENT
The movement or flow of these electrons is called electron current flow or just current.



Definition-
Current is a measure of the amount of electrical charge transferred per unit time.

unit of electrical current is the ampere,
1 ampere can stated as 1 coulomb/second.


WHEN CHARGE STORED AT ANY CONDUCTIVE AREA/SURFACE IT KNOWN AS POTENTIAL

unit of potential on any static surface is volt .

Voltage

difference of potential between two charged surface known as voltage

defination

Voltage is electric potential energy per unit charge, measured in joules per coulomb ( = volts).



REMBER WHEN THERE IS POTENTIAL DIFFERENCE THAN CURRENT FLOW OCCURS IN ANY CONDUCTOR









Electrical and personal safety.
danger’s and preventions

Dangers of Electricity include a variety of hazards as Electric Shock, Psychological Damage, Physical Burns, Neurological Damage ...this may cause deathalso.

The risks caused by electric power can generally be divided into two categories:
direct and indirect.
The direct danger is the damage that the power itself can do to the human body, such as stoppage of breathing or regular heartbeats, or burns.
The indirect dangers of electricity include the damages that can result to the human body as a result of something caused by electric shock, such as a fall, an explosion, or a fire.


While working with electronics circuit/equipment electrical hazards may occurs we can prevent by ensuring following precaution

water and metal are good conductor of electricity so keep away these things fron electric power source

ensure there is proper grounding of all electrical terminals

EARTHING/GROUNDING

Earth is a good conductor and have biggest surface for charge distribution so for preventing electrical hazards we use earth for termination of electrical wire
If you look at a utility pole, you'll probably be able to spot a bare wire coming down the side of the pole. This connects the aerial ground wire directly to ground. Every utility pole on the planet has a bare wire like this. If you ever watch the power company install a new pole, you will see that the end of that bare wire is stapled in a coil to the base of the pole. That coil is in direct contact with the earth once the pole is installed, and is buried 6 to 10 feet (2 to 3 meters) underground. If you examine a pole carefully, you will see that the ground wire running between poles are attached to this direct connection to ground.



Now we are discussing more about current and voltage as our syllabus shedule

so current is the flow of charge. remember charge in form of electrons since electrons are negative charge so current flow is opposite in direction of flow of electronics

current is of two types

here is picture showing two types of current source
DC CURRENT
dc current mean direct current current generated by battery type of source are dc current.
This current having constant magnitude over time


AC current
ac stand for alternating current its magnitude and polarity changed frequently by time cycle
this can generated by rotatery machine such as generators



generation of ac current
as shown above a rotatory magnate moving and generate ac current this is basic fundamental rule of generators


multimeters
Multimeters
The multimeter is the most important electronic test instrument for measuring various electrical parameters like voltage current resistance capacitance polarity
there are two type of multimerers
analog and digital multimeters

Analog multimeters are less expensive, somewhat less precise than digital types. They are best by far for observing the trend of a slowly changing voltage, resistance or current.

Digital multimeters are generally more accurate and easier to read than their analog counterparts. They are best for finding out the precise value of a voltage, current or resistance. A DMM may be a little more robust if you accidentally put it on an incorrect scale. They also may have more functions like capacitance meter, temperature sensor or frequency meter.
Analog multimeter digital multimeter





















electronics component
electronic component divided in two catagories
1 active component
2 passive component

ACTIVE COMPONENTS

The components which produce the energy in the form of
current or voltage are called as active component
such as transistors,diode.

passive component
The components which stores the energy in the form of
current or voltage are called as passive components.
example:inductors,resistors,capacitors etc,.
Active component passive component


SMD DEVICE/COMPONENT

Surface mounted devices (SMD) are active and passive electronics components without
conventional connecting wires
this is conventional resistor and smd resistor


PASSIVE COMPONENT

Resistance

Resistance is the property of a component which restricts the flow of electric current.

Resistance is measured in ohms, the symbol for ohm is an omega .
1 is quite small for electronics so resistances are often given in k and M.
1 k = 1000 1 M = 1000000 .

and responsible component for restricting this flow known as resistor

Resistors used in electronics can have resistances as low as 0.1 or as high as 10 M.
resistance can be symbolized by


color coding of resistances

If we have a resistor than there are two method for identify its value

color coding
by multimeter

color coding not used for smd resistance


there are six color strips on it first three denotes three digit four is multiplier in form of power of 10
and fifth show tolerance as well sixth show temperature coefficient.
Each colour has its value as shown black always show 0,yellow for4 white for 9

we can connect Resistance in following two manner
Resistance in series
resistance in parallel

if resistance connected in series than resultant will be


R series =R1+R2+R3

and

1/R parr= 1/R1+1/R2+1/R3



EXAMPLE

its resultant will be calculaate
1/R=(1/10+1/10)
I/R=(1+1)/10
1/R=2/10
R=10/2=5 OHM

capacitance

A capacitor is a passive electronic component that stores energy in the form of an electrostatic field or we can say it store charge. it have two parralel conducting plates separated by an insulating material called thedielectric.

The capacitance is directly proportional to the surface areas of the plates,
and is inversely proportional to the separation between the plates.
Capacitance also depends on the dielectric constant of the substance separating the plates.

The standard unit of capacitance is the farad, abbreviated.

Learn More
CIO Midmarket Resources
This is a large unit; more common units are the microfarad, abbreviated µF (1 µF =10-6F) and the picofarad, abbreviated pF (1 pF = 10-12 F).








smd capacitors

we have already study smd component so here I want to introduce smd capacitors there are various ty pe of smd capacitor we use following capacitor in pcb
smd capacitors

remember that resistance have mostly black in color while capacitor have cammel brown in color.
This cylindrical capacitor also used here black strip show positive side of capacitor




capacitor in series and parallel

when we connected capacitor in series we have following result


and when we connect capacitor in parallel we got result



so it show result opposite to Resistance means resistance in series and capacitors in parallel are added. And same formula in resistance parallel and capacitance series



TRANSFORMERS

transformers are use for steping up or steping down voltage/current /power
it has two winding primary winding and secomdary winding bounded on core which is made of strips of iron.

It work on principle of faraday law and having equation

here vs=voltage at secondary binding ns =no. of turns of sec winding
vp=primary voltage np= no of turn at prim winding





























Semiconductors
A semiconductor, such as silicon, has properties somewhere between those of a conductor and an insulator. The ability of a semiconductor to conduct electricity can be changed dramatically by adding small numbers of a different element to the semiconductor crystal.

ACTIVE COMPONENTS

DIODE
A diode is an electrical device allowing current to move through it in one direction and not allow current in other direction.

As we see here diode allow flow of current only from positive polarity to negative so it is widely used as switch application

diodes are semiconductor and impurity doped of P and N type of impurity.

So we can say p-n junction diode

because of doping there are two different area of majority carriers occurs where P type of impurity doped there holes are majority carriers and with N electrons between p and n region a junction .so it known as pn junction diode











TRANSISTOR

The transistor is a three terminal, solid state electronic device. In a three terminal device we can control electric current or voltage between two of the terminals by applying an electric current or voltage to the third terminalThe transistor is a three terminal, solid state electronic device. In a three terminal device we can control electric current or voltage between two of the terminals by applying an electric current or voltage to the third terminals



TRANSISTOR
1) Use three layers of silicon.
2) Can be used as a switch or an amplifier.
3) Processor chips are lots and lots of transistors in one package.
3) Transistors have three terminals - the base, collector and emitter.

Types of transistor
There are two types of standard transistors, NPN and PNP

trignometry

Vertex

Definition: The common endpoint of two or more rays or line segments

Vertex typically means a corner or a point where lines meet.


vertex


Angle
Definition: A shape, formed by two lines or rays diverging from a common point (the vertex).

Vertex - The vertex is the common point at which the two lines or rays are joined. Point B is the figure above is the vertex of the angle ∠ABC.

Legs - The legs (sides)of an angle are the two lines that make it up. In the figure above, the lines AB and BC are the legs of the angle ∠ABC.

Interior-The interior of an angle is the space in the 'jaws' of the angle extending out to infinity. See Interior of an Angle

Exterior-All the space on the plane that is not the interior. See Interior of an Angle




FOR STUDY OF TRIGNOMETRY WE HAVE TO STUDY ANGLE SUPPOSE THERE IS ANGLE DENOTED BY A THEN WE CAN SAW






TRIANGLE
A triangle is one of the basic shapes of geometry: a polygon with three corners or vertices and three sides or edges which are line segments.
IN OTHER WORD A TRIANGLE IS A POLYGON WITH THREE ANGLE.
A triangle with vertices A, B, and C is denoted ABC.

geometry(2-d)

geometry is the science of studying basic shapes around us
here we are discussing some basic shapes

CIRCLE

let first think how a circle formed .suppose a got tie with a pole and move around with taking maximum possible distance from pole.than the shape formed call
circle

defination
a plane figure bounded by a single curved line, every point of which is equally distant from the point at the center of the figure





circle










line
A geometric figure formed by a point moving along a fixed direction and the reverse direction




line


triangle

when three points in any plane connected in any fashion by straight lines.
the shape formed called triangle


triangle