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regulate my thoughts to build a video amplifier

Discussion in 'Electronic Design' started by yar, Oct 14, 2004.

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  1. yar

    yar Guest

    hi

    I want build a power amplifier for a video signal from a ccd camera
    I don't know what is the information I need to do this ?
    &what is the steps?


    note : I want make it as push-pull amplifier and I select the
    transistor c1815 as the 1st stage & 2n2222 as the 2nd stage if this
    is wrong what the right transistor number I can use & how I select it


    thank you for any help
    yar
     
  2. Tam/WB2TT

    Tam/WB2TT Guest

    Don't know anything about the C1815, but I have built wideband amplifiers
    and found the 2N2369 to be much superior to the 2N2222 as far as bandwidth
    goes; that is, if you can live with the 15 V breakdown. For PNPs, the 2N5771
    works well. In any case, you will have to frequency compensate the feedback
    loop for good video response. You should be able to find an IC that will do
    the job.

    Tam
     
  3. Tim Wescott

    Tim Wescott Guest

    Tam/WB2TT wrote:

    -- snip --
    Search on "Video Amplifier" at On, National Semi, Freescale, Linear,
    Phillips, etc. You'll find something.

    This can be done with transistors but you'll spend a long time at it.
     
  4. Here's the jellybean C1815
    http://www.semicon.toshiba.co.jp/td...Transistors\en_20030328_2SC1815_datasheet.pdf


    Best regards,
    Spehro Pefhany
     
  5. Spehro Pefhany wrote... Hey, Spef, I thought you preferred the Philips pc1815. I do like the
    Toshiba data sheet better though. Checking a few distributors, I didn't
    find much interest in the 2sc1815, only Farnell had some in stock, at a
    high price. Maybe the 2sc1815's jellybean days are over.

    Mouser recommended the bc546b instead. Hmm, the bc546 family is well
    stocked at distributors, as is its nice little bc556 pnp complement.
     
  6. Toshiba is the original manufacturer, of course. I don't think the
    days are over, it's just not that popular outside Japan and (areas
    that use Japanese designs), and it's an old-fashioned through-hole
    part.
    Have any 2SC parts become popular in the US?


    Best regards,
    Spehro Pefhany
     
  7. Tam/WB2TT

    Tam/WB2TT Guest

  8. My memory might be defective, but isn't the 2N2369 a gold doped transistor?
    (Gold doping apparently used to be used to mitigate some of the storage
    issues for saturated switching?) AFAIR, the gold doping would also likely
    increase the noise from the part (probably LF noise). For full 1V
    video, that isn't likely a major problem, but I wouldn't use a gold
    doped part even for moderately low noise apps. (This is from deep, dark
    recesses of my memory, and might be confused with something else.)

    I do remember that I had played with the old, one/two transistor FM
    transmitter thingies (this was about 40yrs ago), and the 2n706 (also
    a gold doped part) seemed to be fairly noisy at audio, even though
    it was the oscillator.

    Again, I know that the circuit might not be used in an application
    where low noise is very important, but it is possible that such a
    component MIGHT have some small effect on SNR if you are using less
    than full 1V vidoe levels.

    John
     
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