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[opinion request] TV amp - strange simulation results

Discussion in 'General Electronics Chat' started by Antey, Dec 18, 2005.

  1. Antey

    Antey New Member

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    The circuit doesn't work (of course... :? ) but today I'd like to hear an opinion about it's simulation results, and to be more precise - the reason behind AC Sweep results for V/D marker. Where does this 1 [V] come form ?

    Circuit and it's AC Sweep results for selected markers : Voltage/Level i&Voltage/Differential.

    [​IMG]
    [​IMG]

    Source is 10uV @ 425 MHz.

    Any suggestions, except the one I already know (that I shouldn't hold my breath waiting to become circuit designer ) shall be deeply appreciated.

    Amendment : this should work @ 40-890 MHz range.
     
  2. Russlk

    Russlk New Member

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    One volt output is completely unrealistic, the R&-R8 attenuation is 40dB! The input capacitor, C12, will attenuate 10mHz a great deal. I don't have BFR95 in the library so used 2N2369. The stages have no gain to begin with. What kind of simulator do you have that outputs in volts instead of dB?
     
  3. Antey

    Antey New Member

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    Even I know that :?

    Yeap. And I am wondering what else I can do about it.
    I am running out of ideas at alarming rate, and this [..] still does not work, as it should - after all, it's a schema form a kit-shop, that should work...

    PSpice 6.3. With single function, it can also plot dB.
    But with my little expirience, I prefer to have an insight into direct values - helps thinking about makining the circuit work. When it starts to work, I'll switch into dB.
     
  4. dave

    Dave New Member

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  5. Roff

    Roff Well-Known Member

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    I think C11 is connected to the wrong end of R7. I would add an emitter follower as shown. Also note the change in value of R8.

    When you save schematics, save them as .PNG or .GIF files. JPG works well for photos, but it adds a lot of artifacts to line drawings.
     

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