[sdiy] led driver from negative power rail

Derek Holzer derek at umatic.nl
Wed Sep 8 01:05:45 CEST 2010

Can someone please explain this to me:


I'm having a hell of a time getting it to work!!!! I'm using a 2N3906 
PNP in place of the listed transistor. Output is indeed from the Serge 
SSG, either Smooth or Stepped.

How exactly does one drive an LED from the negative rail? I can't Google 
up a single instance of this.

Incidentally, I would just use an LED driver powered from the positive 
rail, except that the Serge modules don't have positive anywhere on the 
panel, all the pots are wired between ground and negative. Sigh....

::: derek holzer ::: http://macumbista.net :::
---Oblique Strategy # 169:
"Use filters"

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