Circuit question

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  1. - 12th July 2015, 13:34 #8
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    Ioannis
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    Default Re: Circuit question

    I would not use a BS250 since it has high leak current.

    Better choice would be a PNP transistor like the BC857 with a BC847 pair to turn it on.

    Resistor would also be dimensioned lower, say c-b at 10K to keep the PNP off and another 10K to turn it on by the other NPN transistor.

    I use such a selection for a commercial product working on a 9V battery. My caps are 10uF and charge through PNP internal resistor with no problem.

    Ioannis
    Last edited by Ioannis; - 12th July 2015 at 13:36.
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