transistor selection help

Discussion in 'General Electronics Chat' started by whale, Dec 17, 2009.

  1. whale

    Thread Starter Active Member

    Dec 21, 2008
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    CAN I USE BFQ136 TRANSISTOR AS AN AMPLIFIER FOR THE FREEQUENCY RANGE ABOUT 13 MHZ?

    I HAVE ITS DATA SHEET . THE TERMS IN ITS DATA SHEET ARE AS FOLLOWS,



    transition frequency(fT) = 4.0 - GHz

    CONDITIONS : IC = 500 mA; VCE = 15 V; f = 500 MHz; Tj = 25 °C;




    please explain me about the term transition frequency.

    is the transistor is suitable for 13 mhz operation?
     
    Last edited: Dec 17, 2009
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    That transistor is not at all suitable.

    Take a look at the site - http://www.kenselectronics.com/lists/orig.htm - and find any transistor rated for the RF output of a CB radio. If it will work at 27 MHz, it will work at 13 MHz.
     
  3. whale

    Thread Starter Active Member

    Dec 21, 2008
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    0
    thanks beenthere ,

    can you tell me whats the term transition frequency mean?
     
  4. whale

    Thread Starter Active Member

    Dec 21, 2008
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    0
    tell me how to choose a transistor based on the frequency of the circuit.
    i mean, what factor in the data sheet is responsible for the frequency of operation?
     
  5. beenthere

    Retired Moderator

    Apr 20, 2004
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  6. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    In a transistor, transition frequency is the frequency where the AC current gain (beta, hfe) equals one.
     
  7. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    Whale, as beenthere said, a transistor with fT=4GHz will be unsuitable. It would be difficult to keep it from oscillating unless you really know what you are doing.
     
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