ORIGINAL MESSAGE:
On Sun, 11 Apr 2010 09:18:45 -0700 (PDT), sasas asasas
<tzitzikas_ee@yahoo.com> wrote:
>Without driving power, we must adjust the current at 200mA (when the linear is
>cold).
>My problem is this: When i tried to adjust the current at 200mA without
>driving power, when the current close to
>160mA (by tuning the variable resistance 5Kohm) suddenly the current takes the
>value 3A and some smoke comes out
>from the input transformer.
REPLY:
It sounds like it is breaking into oscillation. I notice there is a
transformer, T3, which is there to provide negative feedback from
output to input. Perhaps the phase has gotten accidentally reversed?
That would make it oscillate.
73, Bill W6WRT
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