How does a transister amplify voltage???

Once in our class , our prof asked us, how exactly does a transister amplify the voltage given to base,that too to such high values?
The whole class was silent, no answers. I also tried to give some pathetic explanations.
However, here is some explanation to the same..
If you look at the BJT junction carefully,emitter is heavily doped and is smaller in size, so it gives a least resistance path for the current to flow.
The collector has moderate resistance and has large size compared to emitter, plus its reversed biased while operation, so it gives large resistance path for the current.
While the base is lightly doped and has very small area.
We know, Ie=Ic+Ib,
but Ib is very small so Ie is approximately equal to Ic.
But the base region is less resistance path , so current flows through it as such.

Transister Structure

But the collector region has high resistance and its reversed biased, so it forcibly draws more electrons from the supply, which collides with the particles of the collector thus, producing high voltage for the same current than emitter or base(the base hardly consumes 4-6 % of the total emitted electrons.
So the same current is flowing through the high resistance path as the emitter one, so it produces high voltage output, or ampified output.
Thus the voltage is amplified at the collector terminal terminal.

This also explains why output is taken from collector , rather than emitter while operating it as a amplifier.

Your First Circuit...A 5V voltage regulator

Starting with the technical posts ... first lets begin by making a 5V voltage regulator.
This voltage regulator doesn't use a AC voltage as such, because using ac voltage and transformers could be a bit expensive and dangerous too.So essentially we are converting 5v or higher DC supply from a battery into 5V Constant DC.
The main component of this supply design is IC 7805.Its a T220 package IC with 3 terminals,Input, output and reference(in this  case the refernce is ground).Now  the details of the circuit:
Components required:
1.IC 7805 5V voltage regulator
this IC is also available in 12 V and 9 V packages , so be careful to ask for the 5V one.
2. A rectifier bridge
Here we have used a Silicon bridge which can both ac and obviously DC into DC voltages.I have used a WOxx style bridge rectifier.
3.Capacitors:
c1-1000uF
c2-1uF
4. and finally a few connectors.
below is given the PCB layout for mounting through hole components.

A PCB schematic of a 5V voltage regulator.

Note , in the circuit diagram schematic given , dont forget to connect the two points above the bridge using a jumper or some other suitable connctor.
This circuit above works well for both AC and DC.
If you are making only for DC sources, then you can remove the bridge .
the remaining circuit is shown below.

Voltage regulator without bridge.

Any queries about this , feel free to post as a comment and please comment if this post was useful.
Any improvements over the blog will be thankfully accepted.

About the blog

In this blog we are going to discuss about simple circuit schematics using transisters and opamps , other digital IC's .We will also post many mini project ideas , videos,and their details.
Also we will discuss about some major project ideas, softwares like MATLAB,Labview , arduino and avr.
We will touch about some latest technologies coming in our fields.
From the next post onwards we will enter our world of electronics ...so be prepared...

Greetings...

Hi guys..
We are  Shailendra Pundhir and Prateik N, students of Electronics and Telecommunication Engineering,and so is this blog intended for.Its our first blog and in our first few posts we would introduce you about what the blog is and how it is well suited for you.
Looking forward for your participation and comments...