Transistor...?

Discussion in 'General Electronics Chat' started by RRITESH KAKKAR, Sep 15, 2010.

  1. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    Why simple transistor (ex. Bc 558 ) have emitter -base region more doping (low resistance) and in big transistor ( 2n3055) have collector -base region more doped (low resistance) pls reply...!

    Thank's in advance.:confused:
     
  2. marshallf3

    Well-Known Member

    Jul 26, 2010
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    Because they have to make them that way to work. (and if you'd think about the way a transistor works it would make sense anyway)

    In the meantime you might look for a copy of this book:
    http://www.amazon.com/Semiconductor...gy-Michael-Quirk/dp/0130815209/ref=pd_sim_b_2
     
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  3. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    why.........?
     
  4. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    If the same crystal is doped so that each end is n-type and the very thin slice in the center is p-type, the resulting sandwich forms a bipolar junction transistor or n-p-n transistor. In an n-p-n transistor one of the n-type regions is termed the collector, the other n-type region is termed the emitter. (The emitter emits majority charge carriers, and the collector collects them.) The very thin slice of p-type material in the center is termed the base of the transistor. In a p-n-p transistor the collector and emitter regions are made from p-type semiconductor and the base has the characteristics of n-type material. Both n-p-n and p-n-p transistors are in common use but these two transistor types are not directly interchangeable since they require different power-supply polarities. Many circuits employ both n-p-n and p-n-p transistors, but the circuitry must supply the correct voltages. It is common to connect the two types of transistors together in an arrangement that is called complementary symmetry.

    Transistors are able to amplify signals because their design permits the supply of charge carriers to be adjusted electrically. A transistor will have a high electrical resistance when it is starved for charge carriers but it will conduct quite well when a control signal injects extra carriers that can be used to support increased current.


    Read more: The History Of The Transistor, Silicon And Germanium, Doping, P-n Junction Diodes - Transistor action
    http://science.jrank.org/pages/6925/Transistor.html#ixzz0ziH1TZ56
     
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  5. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    why diff. transistor have diff. resistance for what and in multimeter it is given that hfe switch how to use it and what is the benefit of it pls tell.
     
  6. Kermit2

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  7. RRITESH KAKKAR

    Thread Starter Senior Member

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    I don't get my answer.
     
  8. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    You need more basic knowledge of how things work first. You are seeking knowledge of things you do not understand, and the answers only make you ask more questions. If you had a basic understanding of the subject the answers you are being given would provide insight. Instead they confuse you and cause you to ask more and more questions, whose answers confuse you and make you ask even more questions.

    Find basic electronic theory books and read. The world wide web is FULL of pdf's and scanned books that you can download and read. Do so. Your confusion is becoming a frustration for members. You never seem to understand the answer when you get it. You just ask another question about something in the answer.
     
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  9. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    I want to make simple amplifier from one or two transistor as in college lab. the circuit was given of single npn transistor but the output seen in cro was not perfect, pls post circuit of it.
     
  10. marshallf3

    Well-Known Member

    Jul 26, 2010
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    It would be far better if YOU posted a picture of the schematic, the waveform seen on the scope (both at input and ouput) and why you think it doesn't look correct.
     
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  11. RRITESH KAKKAR

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    Jun 29, 2010
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    Sir, i don't have CRO to see waveform...!
     
  12. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    I think you should go see a doctor, ask him about schizofrenia...
     
    Last edited: Oct 10, 2010
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  13. RRITESH KAKKAR

    Thread Starter Senior Member

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    man, i have seen output in college lab in cro, at home i don't have cro...![​IMG]
     
  14. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    Well, then go to college and draw it on piece of paper, or remember how the waveform looks like, or use your cellphone to photograph it and post it here. Isn´t that obvious?
     
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  15. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    But i have LT spice, and it will be great if you post a standard circuit of it.
     
  16. Wendy

    Moderator

    Mar 24, 2008
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    It's funny, I spent less that 10 minutes looking up a simple transistor amplifier last night using Google. It was provided by a small college, complete with a complete description of how it worked. Read, young friend, read!
     
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  17. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    what is mean by stability of amplifier, as for this negative feedback is given??
     
  18. marshallf3

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    By stability they mean it is less likely to oscillate under normal operating conditions.
     
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  19. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    How does amplifier oscillate, i am not understanding??:confused:
     
  20. Audioguru

    New Member

    Dec 20, 2007
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    Why don't you post the schematic of your amplifier so we can see what you are talking about?

    What parts is it using?
    What supply voltage is it using?
    What load resistance is it using?
    What input level?

    Please sketch what a sine-wave input looks like at the output and list the output level.

    EDIT:
    Oh. Are you talking about one of the circuits that we discussed on one of the other websites? (Echo, echo again)
     
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