What kind of part is this and what is it used for?

Thread Starter


Joined Sep 18, 2007
Looks like two diodes/rectifiers, but i'm no expert.
I thought it was just diodes in parallel but I wasn't sure. Maybe someone else can chime in and let me know what in the world they are doing in that feedback loop.


Joined Apr 20, 2004
Those are dual diodes, with pin 3 as the common cathode. The whole network is not visible, so their function is a bit of guesswork. The 680 pF cap is probably a feedforward high frequency suppressor. The ratio of the 100K R38 and the two input resistors, R33 & 35 set the gain in the positive direction... But there is more stuff below the summing junction, so who knows. The two dual diodes are connected so their two diodes are in parallel, and are both in series, and clip the negative signal transition - assuming there is one.
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