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  1. #1
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    Class B wave form problem

    Hello,
    I am going to see the output waveform of class B amplifier. First of all, I tested this circuit
    Click image for larger version. 

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    For low frequency (200Hz-200Khz) I see this waveform at the output.
    Click image for larger version. 

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    But by increasing the frequency value up to 2Mhz, I see the input frequency exactly at the output without any disturbance( I see that It has low disturbance and some undesired frequencies that I can't see them on the oscilloscope without any FFT function) while the FT of transistor is more than 100Mhz.

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    So I need to know why I see the same waveform in output.

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  2. #2
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    Re: Class B wave form problem

    Hi,

    At high frequencies you most probably see the capacitive coupling from base to emitter.
    I assume this also works without supply. It's passive.

    The active circuit - at low frequencies - is not able to generate negative voltages.

    Klaus
    Please don´t contact me via PM, because there is no time to respond to them. No friend requests. Thank you.


    1 members found this post helpful.

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