[sdiy] Capacitors questions

[Scott Gravenhorst]

harrybissell <harrybissell at prodigy.net> wrote:
>Hi Ryan et al
>
>search Google for "capacitors" and "Harry Bissell" to find my FAQ.
>Its on a whole bunch of sites including a few I never dreamed of :^P
>
>You can find Polystyrene caps at www.mouser.com under the Xicon
>brand.
>
>The direction of the cap is important, especially in the rabid types like
>Tantalum (they blow violently)
>
>The presumption is... you hook the "+" to whatever side of the circuit
>is more positive with respect to DC.   Sometimes from the circuit, there
>is no doubt which side that is...
>
>When the cap is being used to set a limit on frequency response... sometimes
>
>there is NO net DC there.  Other times the polarity is unknown,
>
>They make a type of cap called "Non-polar" Electrolytic.  I use these for
>all my
>coupling caps that are larger in value than I can get with FILM capacitors
>(usually
>this is somewhere around 0.5uF)

Non polar electrolytics: just to refresh my memory, are these something
special in construction or are they really just two polar electrolytics that
are series connected + to + or - to - ???  In other words, can a nonpolar
electrolytic be made DIY using two equal value polar electrolytics? 
(Obviously, the capacitance would be halved...)

>helps ???
>
>H^) harry
>
>Ryan Williams wrote:
>
>> hi all,
>>
>> I've got a simple question here about electrolytic capacitors. I
>> understand that the positive side has to have a greater voltage than the
>> negative side or else it will explode, but I don't understand how they
>> work with AC signals when blocking the DC part of the signal. like this:
>>
>> module_input----||-----module
>>                    +
>> incase it doesn't show up right, the '+' side is on the 'module' side.
>>
>> how does this work? I've seen this on many synth diy schematics, but all
>> the capacitor tutorials I've seen do not talk about this. It just
>> doesn't make sense to me since the signal is AC.
>>
>> -----------
>>
>> one more question: Does anyone know where to find 1% polystyrene
>> capacitors in the US? I need them in 100nF sizes.
>>
>> Thanks,
>> Ryan
>

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