Nano-technology and Nano-science

The latest and sensitive topic of new generation is nano-technology. Nano technology is the science ,engineering and technology conduct at nano scale i.e about 1 to 100 nano scale. Nanotechnology and nano science are the study and application of extremely small things and can be used across the field of science like biology, chemistry, physics, math, engineering, and material science. It is hard to imagine that how small nano technology is. One nano meter is just equal to 10^-9 of a meter.  The father of nanotechnology was Physicist Richard Feynman .

It is one of the interesting topic of science and technology. It is involve in the ability to see and prevent individual atoms and molecule, Earth where we are surviving our life is made up of these small atoms for eg;- the food we eat, the clothes we wear, the building and house we live and our bodies too. We are not able to see some of small atom with our naked eyes. And also impossible to see with the microscope which we used in our high school science class. The microscope need to see nano scales thing were invented 30 years ago.

Application of nano technology .

Nano technology can be use in every sector related with science and technology as shown in the given figure.

a)Medical science 

Nanotechnology is used to treatment of disease.Nano-medical ranges from the medical application of nano-material and biological devices like biosensor and even future application of molecular nanotechnology such as biological machines. Nano material can be useful for both vivo and vitro biomedical research and its application. And it lead to the development of diagnostic devices, contrast agents, analytical tools, physical therapy application and drugs delivery vehicles.

b)Nano biotechnology 

Nano biotechnology, biotechnology, nano biology are the terms derived from the intersection of nanotechnology and biology. Its help us to biological research with various field of nanotechnology. Nano devices such as biological machines, nano particals, and nano scale are the biological term of nanotechnology.

c)Industrial 

 Nano technology is also used in industrial sector to easier their work. Its is used to easy to clean to scratch  resistant for example car bumper are made lighter, clothing is more stain repellent, sunscreen is more radiation resistant, cell phone screen are lighter weight and many more. Using of nano tech change all the electronic appliance of industries make smart through embedded wearable electronics.

How gate work

Logic gate

 The digital circuit which follows the logical relation between input and output voltages. Its system is depend in only two numerical input i.e. 0 or 1 here 0 refer to low and 1 refer to high. In this gate there is only one output for one or more than one input. There are different type of logic gate they are 

1) OR gate 

2) AND gate

3) NOR gate

4) NAND gate

1) OR gate
It is the logic gate which provide the high output if one of the input is high. It has two or more than two input and only one output. It can express as Z=X+Y.

Explanation of OR gate

The circuit diagram of OR gate using two diode D1 and D2 as shown in figure. A and B are input and Y is output. Here  0 potential mean 0 state and positive mean 1 state. The operation of OR gate is explained as follows:

• When A is 0 volt and B is also 0 volt then the diode D1 and  D2 don't conduct current hence there is no flow of current through the diode as well as load resistance Rl. So output is low i.e   Z=X+Y=0+0=0.
• When A is 0 volt and B is +5V volt then the diode D1  don't conduct D2 conduct current hence there is flow of current through the diode D2 as well as load resistance Rl. So output is high i.e Z=X+Y=0+1=1.
•  When A is +5V volt and B is 0 volt then the diode D1 conduct current but D2 don't conduct current hence there is flow of current through the diode D1 as well as load resistance Rl. So output is high i.e Z=X+Y=1+0=1.

• When A is +5V volt and B is +5V volt then the both diode conduct current hence there is flow of current through the diode as well as load resistance Rl. So output is high i.e Z=X+Y=1+1=1.

2) AND gate

 It is the logic gate which provide the high output if both the input is high. It has two or more than two input and only one output. It can express as Z=A.B

Explanation of AND gate

The circuit diagram of AND gate using two diode D1 and D2 as shown in figure. A and B are input and Y is output. Here  0 potential mean 0 state and positive mean 1 state. The operation of OR gate is explained as follows:

• When A is 0 volt and B is also 0 volt then the diode D1 and  D2 don't conduct current hence there is no flow of current through the diode as well as load resistance Rl. So output is low i.e   Z=X+Y=0+0=0.
• When A is 0 volt and B is +5V volt then the diode D1  don't conduct D2 conduct current hence there is flow of current through the diode D2 as well as load resistance Rl. So output is high i.e Z=X+Y=0+1=1.
•  When A is +5V volt and B is 0 volt then the diode D1 conduct current but D2 don't conduct current hence there is flow of current through the diode D1 as well as load resistance Rl. So output is high i.e Z=X+Y=1+0=1.

• When A is +5V volt and B is +5V volt then the both diode conduct current hence there is flow of current through the diode as well as load resistance Rl. So output is high i.e Z=X+Y=1+1=1.

3) NOR gate

 It is the logic gate which provide the high output if  both the input is low. It has two or more than two input and only one output. And the logic gate provide low output if both then input is high. Its work as shown in the given truth table. Its can be express as X = A+B.

Explanation of NOR gate

The circuit diagram of NOR using two diode D1 and D2 as shown in figure.A  and B are input and X is output. Here  0 potential mean 0 state and positive mean 1 state. The operation of NOR gate is explained as follows:

• When A is 0 volt and B is also 0 volt then the diode D1 and  D2 conduct current hence there is flow of current through the diode as well as load resistance Rl. So output is low i.e   X = A+B=0+0=1.
• When A is 0 volt and B is +5V volt then the diode D1 and D2 don't conduct current hence there is no flow of current through the diode as well as load resistance Rl. So output is low i.e X = A+B=0+1=0.
•  When A is +5V volt and B is 0 volt then the diode D1 and D2 don't conduct current hence there is no flow of current through the diode as well as load resistance Rl. So output is low i.e X = A+B=1+0=0.

• When A is +5V volt and B is +5V volt then the diode D1 and D2 don't conduct current hence there is no flow of current through the diode as well as load resistance Rl. So output is low i.e X = A+B=1+1=0.

4) NAND gate

 It is the logic gate which provide the low output if  both the input is high and if one of the the input is low then its output is high. Its can be express as AB=A+B.

INPUT		OUTPUT
A	B	A NAND B
0	0	1
0	1	1
1	0	1
1	1	0

Explanation of NAND gate

 The circuit diagram of NAND gate using two diode D1 and D2.A  and B are input and Q is output. Here  0 potential mean 0 state and positive mean 1 state. The operation of NAND gate is explained as follows:

• When A is 0 volt and B is also 0 volt then the diode D1 and  D2 conduct current hence there is flow of current through the diode as well as load resistance Rl. So output is low i.e   AB=A+B=0+0=1.
• When A is 0 volt and B is +5V volt then the diode D1 and D2 conduct current hence there is flow of current through the diode as well as load resistance Rl. So output is high i.e AB=A+B=0+1=1.
•  When A is +5V volt and B is 0 volt then the diode D1 and D2 conduct current hence there is flow of current through the diode as well as load resistance Rl. So output is high i.e AB=A+B=1+0=1.
• When A is +5V volt and B is +5V volt then the diode D1 and D2 don't conduct current hence there is no flow of current through the diode as well as load resistance Rl. So output is low i.e AB=A+B=1+1=0.

How the transistor help in our daily life.

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Transistors believe semiconductors to figure their magic. A semiconductor may be a material that’s more or less a pure conductor (like copper wire) however additionally not associate material (like air). The physical phenomenon of a semiconductor – however simply it permits electrons to flow – depends on variables like temperature or the presence of a lot of or less electrons. Let’s look shortly beneath the hood of a junction transistor. Don’t worry, we have a tendency to won’t dig too deeply into physical science.

A junction transistor as two Diodes

Transistors are reasonably like associate extension of another semiconductor component: diodes. in an exceedingly method transistors are simply 2 diodes with their cathodes (or anodes) tied together:

Transistors as 2 diodes

The diode connecting base to electrode is that the necessary one here; it matches the direction of the arrow on the schematic image, and shows you which of them method current is meant to flow through the junction transistor.

The diode illustration may be a sensible place to begin, however it’s removed from correct. Don’t base your understanding of a transistor’s operation thereon model (and positively don’t attempt to replicate it on a bread board, it won’t work). There’s an entire heap of weird physical science level stuff dominant the interactions between the 3 terminals.

(This model is helpful if you wish to check a junction transistor. exploitation the diode (or resistance) take a look at perform on a multimeter, you'll be able to live across the BE and before Christ terminals to visualize for the presence of these “diodes”.)

Transistor Structure and Operation

Transistors ar designed by stacking 3 completely different layers of semiconductor material along. a number of those layers have additional electrons additional to them (a method known as “doping”), et al. have electrons removed (doped with “holes” – the absence of electrons). A semiconductor material with additional electrons is termed associate n-type (n for negative as a result of electrons have a negative charge) and a cloth with electrons removed is termed a p-type (for positive). Transistors ar created by either stacking associate n on prime of a p on prime of associate n, or p over n over p.

Simplified NPN construction

With some hand waving, will|we will|we are able to} say electrons can simply ensue n regions to p regions, as long as they need a trifle force (voltage) to push them. however flowing from a p region to associate n region is admittedly exhausting (requires plenty of voltage). however the special issue a few junction transistor – the half that creates our two-diode model obsolete – is that the undeniable fact that electrons will simply ensue the p-type base to the n-type collector as long because the base-emitter junction is forward biased (meaning the bottom is at a better voltage than the emitter).

Active junction transistor current flow

The NPN junction transistor is meant to pass electrons from the electrode to the collector (so typical current flows from collector to emitter). The electrode “emits” electrons into the bottom, that controls the quantity of electrons the electrode emits. Most of the electrons emitted ar “collected” by the collector, that sends them on to consequent a part of the circuit.

A PNP works in an exceedingly same however opposite fashion. the bottom still controls current flow, however that current flows within the wrong way – from electrode to collector. rather than electrons, the electrode emits “holes” (a abstract absence of electrons) that ar collected by the collector.


The junction transistor is reasonably like associate negatron valve. the bottom pin is sort of a handle you would possibly suits enable a lot of or less electrons to ensue electrode to collector. Let’s investigate this analogy further…