It seems everybody is following the quote "Issue a general safety warning. Then look the other way and allow stupidity the chance to eliminate itself."
But for other enthusiastic DIY hobbyist, I managed to dig out some information which may me helpful to someone we reads this post later.
The article states :
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"A polarized capacitor forms the dielectric between the conducting plates electrochemically. Voltage must be applied in one direction only across the conducting plates to form the dielectric insulating film. The applied voltage across the capacitor must always be in a particular direction, and the capacitor is externally marked to indicate the proper voltage polarity. Reversing the applied voltage can cause the insulating film to rapidly fail, and can cause the capacitor to actually explode from rapid production of gas within the shell of the capacitor.
A non-polarized capacitor uses a dielectric material with uniform insulating properties (such as mylar, mica, glass, etc.), and can be installed in a circuit without regard for the polarity of the applied voltage.
Also polarized capacitors have big capacity in small size (above 1 microf), non-polarized capacitors can have big capacity but sizes are very big.(So they are unuseful in most projects) "
Question : "Can I paralell 2 polar cap to form a non-polar cap ? "
Answer : NO YOU CAN'T.
Dielectric of polarized capacitor is Al2O3 for Aluminium and TaO2. for tantalum capacitors. Polarized cap. must be under minimal 2V DC otherwise is dielectric resolved.
It is possible to form this cap. on a higher voltage.
You must connect them antiserial. That means + polarity connected together and - and - used externally. Or viceversa. Voltage rating is as for single capacitor.
In some applications you can use serial pol. cap (+--+ or -++-) with parallel diodes (CAAC or ACCA)
You can use caps back to back for non-critical applications, it is better to use them in conjunction with the diodes, but their characteristics will never be exactly the same as a true non-polarized cap.
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Although, that technical lingo did explain something to me, yet I am still on, square one.
How to find the value of Pol. cap. to be used for substitution for non-Pol. caps.