polarity layout of caps

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polarity layout of caps

Postby fireflyva » 12 Aug 2013, 02:36

Question: I'm new at this so please bear with me.

Regarding the schematic: download/file.php?id=16595

when reading the capacitor C11 which is a 2u2 capacitor and polarized (at least from the parts list), how do you know how to orient the + side if the schematic isn't marked? There are several capacitor symbols on the schematic, and some are values low enough that they do not belong to polarized caps. However, some are polarized but the schematic doesn't show which side to insert the + versus the negative.

How are those things understood?

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Re: polarity layout of caps

Postby Intripped » 12 Aug 2013, 09:47

so, you're referring to this layout from plesur
...and in this layout plesur used film caps for C8-9-10-11 (all 2,2 Uf); only C7 is polarized (electrolytic)
if you scroll down the thread page you can see some pics of his build also: some big WIMA 2,2 Uf film caps are used
so you don't see the polarity in the schematic because those are film (non-polarized!) capacitors!

...but if you search a little you can find at page1 of that thread the version 0.2 of the schematic (slightly different from version 0.3, and with polarized caps)

now, take C11: in this schematic you see that the + side is toward pin 3 of the IC
look at the layout now: can you see the trace connecting C11 to pin 3 of the IC? well, now you know where the + goes.

EDIT: if you look at the pics of the original pedal (always at page 1) you could also verify plesur's reverse-engineering work: can you see C11? is the little red TANTALUM (polarized) cap (...so yes: in the original effect tantalum capacitors are used). can you see the "+" marking on the PCB? the trace on the PCB connects the + side of the cap with pin 3 of the IC, you see that? ...ok, now you're REALLY sure about C11 orientation.

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fireflyva (12 Aug 2013, 11:27)
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Re: polarity layout of caps

Postby karul » 12 Aug 2013, 10:05

Connect the negative side with the emitter. (It's the 1uF on this schematic)
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