transistor as an amplifier

vk6zgo

Joined Jul 21, 2012
677
Transistors,like other amplifying devices amplify by using the signal which requires amplification (input signal)to control a larger current from (normally) a dc source.

Imagine a voltage divider------If you were able to vary one element of the divider so that it follows the variations in the input signal,you would have amplification.

This is,in effect,what happens in BJTs,FETs,& Vacuum tubes.

the Physics behind the differing ways this is achieved in all the above devices is too complex to include in a quick answer here,hence the suggestion to "read up on it!" :D

There are many books, old & new which go into the details of how BJTs work.
 

ErnieM

Joined Apr 24, 2011
8,377
hello all
how transistor works as an amplifier ? i want to know about transistor works as an amplifier with example plz help
Oh it is very simple: you put something into a transistor, and something else comes out, but that other thing is even bigger then the thing you put in!

That is amplification. Thus endeth the lesson.
 

MrChips

Joined Oct 2, 2009
30,795
Think of a control valve that controls the flow of water through a pipe.
I turn a knob or handle and I can open or shut off the water flow.

Now suppose I was able to control the knob or handle with a small flow of water.
Then I have created an amplifier. A small amount of water flow can control a larger amount of water flow.

That is how a BJT amplifier works. Instead of water flow it works with electron flow.
 

Potato Pudding

Joined Jun 11, 2010
688
hello all
how transistor works as an amplifier ? i want to know about transistor works as an amplifier with example plz help

Congratulations! You are the thousandth person to ask this question here on these forums. Bonus sarcasm in your replies for using very sloppy writing practices in your question. No capitals. Sketchy grammar and punctuation. Extremely general question. Indication that your question is very important but using plz.

There are some things that will make your questions gather better responses. Showing that you really do care and that you are not lazy helps. Showing that you have the intelligence to grasp the concepts you are looking for helps. Showing that you can communicate in a professional manner with a considerable level of interest.

Your question sounds like a lazy kid that wants somebody to do three weeks of missed homework for them, so that they can go back to playing video games. Imagine the response that gets you.

Be more specific.
Show what research you have done on your own. This site has plenty of resources to answer your question in the E-Book chapters. Mention if you have already looked through those.

Vol. III Semiconductors > Chapter 1 >Amplifiers
Vol. III Semiconductors > Chapter 2 > Bipolar Junction Transistors
Vol. III Semiconductors > Chapter 4 >the various amplifier configurations.


Look through all of that and tell us why you expect your forum question to get a better answer than the Ebook provides.

Do not get hurt feelings
from the harsh responses, without understanding how you earned the harsh responses, and that they were not truly harsh - just hazed and wondering if there was any point. Your question was so broad and minimal, showing nothing but slack. The answer is big and a lot of work. You need to show something before we will believe that you can actually use anything we provide; that we would not be wasting our time.

Something like this.

Hello,

I am still learning english and forgive any problems my questions have.
I am a Junior High School student, and I am wanting to use a transistor in a project where it will amplify some energy from an earthquake sensor I have tried to make.
I do not know anything about transistors or amplifiers and I realize that I need a lot of help and it seems very complicated to me.
I have looked at some of the material on transistors and amplifiers that are on this website and they seem to be the best help I have found on the web.

I think I understand gain a little bit now, but not impedance or what type of amplifier configuration I would need to use.

I intend to use the sensor as input into an audio microphone type of connection on a computer where I can record and process the signals. I am not sure if this will work because of the low frequency of the signals. My main project is in the computer programming side which is my hobby.

If you had asked that question instead of the question you did ask then you would have gotten about $10k worth of responses by now. Really. That is what the worth of some of the experienced people that contribute here could work out to in consulting fees. They give that away because sometimes electronics is work and sometimes it is fun. Respect that and it will be very helpful for you in your future postings.

 
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