HELP....BASICS OF TRANSISTORS(Any help will be appreciated!)

Discussion in 'General Electronics Chat' started by anuragmash, Jun 26, 2011.

  1. anuragmash

    Thread Starter New Member

    Jun 26, 2011
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    I understood the transistor action(emitter-base voltage acts like a gate and allows more electrons to diffuse into the collector region and the voltage applied to collector acts like a suction to [disallowed word] all the electrons) but now when we have different configurations such as "Common" Emitter and "Common" Base,
    1) I don't understand what is the difference between the two!!!
    2) In both the cases the base-emitter region is forward biased and collector base reion is reverse biased. So what is the difference between the two??
    3) How does the common terminal control the current between the other two regions?
    4) What do you mean by grounding? Please help me visualize!!!!
    PLEASE HELP!!!!!!!!!!!!!!!!!!!!!
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
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    These links will help you:
    http://en.wikipedia.org/wiki/Common_emitter
    http://en.wikipedia.org/wiki/Common_base
    http://en.wikipedia.org/wiki/Common_collector
    Basically (sic), whatever follows "common" is connected to a fixed voltage reference point that is shared by other components in the circuit, such as ground, +V, etc.; so you know that the named terminal is not an input or output; it is a constant - the two remaining terminals are the inputs and outputs.
    In these three basic configurations:
    1) The collector is never an input.
    2) The base is never an output.
    3) The emitter is the only terminal that is used as an input in one configuration (common base), and an output in another configuration (common collector).
     
  3. Wendy

    Moderator

    Mar 24, 2008
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    Pretty good definitions. There are three, as has been mentioned. They each have advantages and disadvantages. Some are better voltage amplifiers (common emitter), some are better current amplifiers (but not voltage, common collector), and some are somewhere in between (common base, really good for RF). Basically you have to learn all three. I'd say Common Emitter is the most popular, with Common Collector not too far behind, and Common Base the least used.

    I missed some basic concepts while I was in college. Learned the drawings, learned the formula's, but didn't really understand some of what I was dealing with until a fellow tech gave me Malveno's Transistor Basics. With the help of the book I sat down and derived all the formula's from scratch. At that point I could say I understood them, but now and then I still have details catch me off guard.
     
  4. Cyclone1

    New Member

    Jun 27, 2011
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    Hi Bill, I see that you mentioned Malveno's Transistor Basics, I am interested to look into it but I am not able to get similar result after googling. Is the title of the book is the same as per you mentioned?
     
  5. signupsr

    New Member

    Jan 21, 2011
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    Last edited by a moderator: Jun 27, 2011
  6. anuragmash

    Thread Starter New Member

    Jun 26, 2011
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    so basically what does the common terminal do? In the sense, how does it "control" the current in the other two regions...Can you please elaborate......?????
     
  7. RRITESH KAKKAR

    Senior Member

    Jun 29, 2010
    2,831
    89



    I know what you want to ask is that how to use transistor as you have learn theory but not aware of using it....!!

    for learning transistor Remember these four step:-

    i/p o/p sides

    1.) F.B F.B. ( for switching i.e. only on/off)
    2.) R.B. R.B. ( for " " )
    3.) F.B. R.B. ( for amplification i.e. active region)
    4.) R.B. F.B. ( inverting modes not used )


    switching modes is easy than amplification, for amplification first you have to laen switching now try with simple BC 547, BC 548)

    I am also not so much aware of biasing, other member can sure help you..!!
     
    Last edited: Jun 27, 2011
  8. Wendy

    Moderator

    Mar 24, 2008
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    I may be misremembering the name. I'll post it when I have my hands on the book.
     
  9. Jaguarjoe

    Active Member

    Apr 7, 2010
    770
    90
    Search for Malvino at Amazon books, he has a number of books, some for transistors. Used ones are quite cheap but a tad outdated. The basics haven't changed though.
     
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