Why transistor is so special?

[iVenki]

I don't even know anything about transistor until I reached 12th grade. Now in college I am studying fully about transistors. What makes these transistors so special? Why do we use transistors everywhere?

 

[keith1200rs]

They can amplify. That is also true of valves. It is the one thing that makes many other ideas possible.

Keith

 

[rb40040]

the output current of a transistor is more than the input ie they have amplified the current
thus they used as amplifiers and switches

 

[biff44]

They can use smaller batteries than vacuum tubes!

 

[engrMunna]

In transistor we use a very small input signal to control a large output signal..........in analogy maybe you can consider the example of a water reservoir, a dam, if you turn a small valve(the gate voltage of a FET or the input current of a BJT) it will open a large gate(form a channel in FET between drain and source) which will cause a large amount of water(current) to flow through the dam.
So by applying a small force on the water valves you opened a gate which caused large amount of water to flow through it, hence amplification (a small signal causing a large effect)

---------- Post added at 00:49 ---------- Previous post was at 00:49 ----------

they can also be used as digital switches

 

[hussain_kiet]

transistor is no doubt the most important component in electronics...
every electronic devices we use from processor, memories, amplifiers and all other electronic devices there are transistors doing the real stuff at the semiconductor level....

 

[ravics]

Its such a fast switch..

 

[Deepikaaa]

Hi... I m not so familiar in electronics that raised one doubt that how can we say that a transistor is an amplifier??

Because.. the input current which is produced by Vbe is just controlling the collector current(is this caused by Vce???).. then how can we say it as amplifier??
thank u so much..

Deepsss...

 

[umesh49]

"Because.. the input current which is produced by Vbe is just controlling the collector current(is this caused by Vce???).. then how can we say it as amplifier??"

Because due to this interesting current transfer phenomena it actually produce an amplified magnitude linear output voltage.
For a simple understanding, transistors are so special as we can control large current/voltage by using a small magintude signals...

 

[Deepikaaa]

still i am not so clear abt this sir...

 

[LvW]

still i am not so clear abt this sir...

Let me try an explanation:
At first, the transistor alone cannot act as an amplifier.
It functions as a kind of analog gate: A control voltage steers the amount of current that flows through the unit (from collector to emitter or from the drain to the source). This current is driven by the suplly voltage. There is no amplifying effect because the control voltage (B_E or G_S, respectively) only controls the current flow.
Now - when this current flows through an external resistor that is large enough, a voltage can be created across this resistor that is larger than the input (control) voltage. That`s the secret of the amplification.
Does this help?

---------- Post added at 21:33 ---------- Previous post was at 21:15 ----------

Finally, for clarification purposes: The base current of a BJT does NOT control the collector current. In contrary, it can be regarded as a "parasitic" current that cannot be avoided. That´s the big advantage of a FET: It "avoids" such an input current.
The term "current amplification" has no physical meaning. It only reflects the fact that both the collector and the base current have a ratio that is approximately fixed. By the way, this subject has been discussed several times in this forum.

 

[Deepikaaa]

I got it.. Thank you for yr explanation sir.

Deep..

 

[vividvilla]

First of all Transistor is small It is the main reason for rise of transistors and fall of vaccum tubes.will you buy a cellphones which is in the size of bricks...that is the difference

second It is faster than vaccum tubes ,we always have affinity to faster things like fastest cars etc...

 

[yadavvlsi]

You can arbitrarily get any functionality using transistors. Millions of transistors can be fabricated on a single chip to get highly complex functionality (Intel Core2duo,i3,i5,DSP processors). Transistors are small in size, consume small amount of power. If transistor is not there you will not have a smart phone having megapixel camera, built in modem, MP3 player, Wi-Fi, Video recording, GPS etc with battery back of many days. Transistor can amplify also.

 

[kandhu26]

There is no electronics [or we can say electronic gadgets] without transistor... Mother of electronics...