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Oscillator stable frequency to the temperature using MOSFET and Crystal Quartz

Discussion in 'Electronic Design' started by Jhoberg, Mar 26, 2007.

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  1. Jhoberg

    Jhoberg Guest

    This circuit is a Oscillator with frequency stable, use a un MOSFET N-
    channel enhancement mode vertical D-MOS transistor (BS108), a Crystal
    quartz a 24MHz, is a Oscillator a low cost and
    stable frequency to the temperature. Util for applications AM and FM.

    +8VDC +8VDC
    | |
    | |
    | /
    | \100
    | /
    | \
    + +
    / 10M |
    \ +------------/\/\/\--------+---------------o AC signal to
    24MHz
    /10K | |
    \ | Osc 24MHz |
    / +----|o|-----------------+--------------+
    \ | | |
    | | | |
    | | | |------+ |
    | | | |<--| ^ Bs108.......|
    +------+---------------| |___|_| |
    | + |
    | | |
    | | |
    | | |
    | | |
    / / --- 22p
    \3.3K \ ---
    / /10 |
    \ \ |
    | | |
    | | |
    | | |
    --- --- ---
    /// /// ////
     
  2. Ban

    Ban Guest

    Well, your ASCII got all messed up, try AACircuit www.tech-chat.de to draw.
    But guessing it seems as stable as any crystal oscillator. You also have to
    hope the Vgs of the transistor is pretty reproducable, so your output
    doesn't blow up the following stages with that low impedance and high 8V. It
    will consume all the power of the supply maybe 50mA and the low voltage
    never even reaches the TTL threshold of 0.8V.
    Then where do 8V come from, it is not a common supply voltage. With a single
    inverter gate you are better off.
     
  3. Jhoberg

    Jhoberg Guest

    if the resistance of 10R is replaced by an antenna that in the
    resonance frequency is of 10Z, we have a power of 0.1W(R.M.S) in the
    out. With another signal in Vgs is a mudulador of 0.1W(R.M.S).
    To greater power when coming out, greater reach of the trasmisor.
     
  4. Fred Bartoli

    Fred Bartoli Guest

    Jhoberg a écrit :
    Now I do like the mudulator.
    And 0.1Wrms (0.14W pig) isn't bad at all and might be useful to some ham.
     
  5. Ban

    Ban Guest

    I don't understand what you want to say. Seems Portugues to me.
    If you replace the 10R with an antenna, you don't get any output, since the
    DC operating point will be wrong. You could use a transformer here, since
    you won't find a 10R antenna anyway. Your Xtal might also blow up without a
    series resistor. And modulation will not improve this either. Doubtful if it
    works at all.
     
  6. Jhoberg

    Jhoberg Guest


    I do not understand, can speak without animals,
    one talks about 0.1W (R.M.S) , sice system supported that maintained
    to power.
    In that context, it means the average power when reproducing a single
    tone, but it's not actually the RMS value of the power.

    Example
    http://www.kellyindustries.com/amplifiers/mackie_m2600.html


    It would have to read but of Electronics that of kitchen.
     
  7. Fred Bartoli

    Fred Bartoli Guest

    Jhoberg a écrit :
    +8VDC +8VDC
    | |
    | |
    | /
    | \100
    | /
    | \
    + +
    / 10M | AC signal to 24MHz
    \ +-------/\/\/\------+---------------o
    /10K | |
    \ | Osc 24MHz |
    / +---|o|-------------+--------------+
    \ | | |
    | | | |
    | | | |----+ |
    | | | |<-| ^ Bs108...... |
    +----+------------| |__|_| |
    | + |
    | | |
    | | |
    | | |
    | | |
    / / --- 22p
    \3.3K \ ---
    / /10 |
    \ \ |
    | | |
    | | |
    | | |
    --- --- ---
    /// /// ////
     
  8. MooseFET

    MooseFET Guest

    It looks wrong to me.
    The 10M serves no purpose.
    The 3.3K/10K bias circuit values should be increased.
    There should be a capacitor from the gate of the MOSFET to ground.

    If you want a stable oscillator, you want the impedances seen by the
    crystal to not depend on the parameters of the MOSFET. Every
    parameter of a MOSFET including the color changes with temperature.

    You also want to keep the resistances either way more or way less than
    the impedances at the crystal. This prevents the resistances from
    lower the Q.

    For stable frequency, you want the amplifier to have just enough gain
    to ensure starting and have the running gain reduced by the transistor
    going into cutoff. This makes the amplitude less stable than it could
    be but makes the frequency not depend on transistor characteristics as
    much.

    For stable amplitude, you want the limiting to be in the form of
    bottoming of the transistor. Unfortunately, this makes the frequency
    depend more on how the transistor acts just as the drain voltage goes
    around zero volts and also lowers the Q because some of the energy in
    crystal is taken away by the transistor.
     
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