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  1. #1
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    Need help with a Hartley Oscillator .. plzzzz ?

    hi

    Im trying to construct a Hartley Oscillator.
    I am using a bypassed common emiter and i am trying to get a 200kHz 2Vp-p oscilation. With a BC547B npn transistor

    I know how calculate the correct frequency output.
    But i do need help with the following however:

    How do i go about calculating the amplitude of the feedback and output voltage?
    Do the Lower and Upper cutoff frequencies of the amplifier matter ?
    What should the Av (Gain) for the amplifier be +- ?

    Any other pointers on how to start analyzing a circuit for certain criteria would be helpfull.

    Tnx for any help in Advance

    •   Alt13th April 2010, 19:25

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  2. #2
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    Need help with a Hartley Oscillator .. plzzzz ?

    Go through this... might help you

    http://www.edaboard.com/viewtopic.ph...hlight=hartley



    •   Alt14th April 2010, 05:12

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  3. #3
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    Re: Need help with a Hartley Oscillator .. plzzzz ?

    Use a Medium wave antenna coil, with ferrite rod. In absence, take 8mm ferrite rod, Large coil 32SWG Super enameled 80 turn. Small feedback coil 8 turn. Resistor-100K-10K Ohm, feedback capacitor 220pf. Connect 220pf Capacitor parallel with PVC 2J Gang (Variable capacitor) across +Vcc and Collector. Adjust. If require, vary the capacitor value.

    Thanks



    •   Alt15th April 2010, 06:38

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  4. #4
    Junior Member level 3
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    Re: Need help with a Hartley Oscillator .. plzzzz ?

    If you connect the tuning capacitor across +Vcc and the collector of the transistor, you'll have a different kind of oscillator. To make a Hartley oscillator, the tuning capacitor should be placed between the two ends of the coil, see below.


    Here is another Hartley oscillator circuit:



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