Hi!

I would like to know what are bi-directional capacitors? How do they differ from other caps?

Matt

 

You mean bipolar caps, the one you wear to disguise the OCD?

 

You mean bipolar caps, the one you wear to disguise the OCD?

i mean the two 10μF electrolytic capacitors being used in the attached image

 

Digikey sells Japanese non-polarized electrolytic capacitors.
You can connect two ordinary polarized electrolytic capacitors back-to-back (negative wire connected to negative wire) to make your own non-polarized electrolytic capacitor.

 

what is their function/purpose in this amplification circuit here?

 

They couple the output of the first stage to the second stage. If the first stage output swings both positive and negative with respect to zero, then bipolar capacitor, or the arrangement shown is needed. If the output of the first stage has a DC bias level and the signal only increases and decreases this level without going through zero, then a single polarized cap could be used.

 

Digikey sells Japanese non-polarized electrolytic capacitors.
You can connect two ordinary polarized electrolytic capacitors back-to-back (negative wire connected to negative wire) to make your own non-polarized electrolytic capacitor.

are the two 10μF electrolytic capacitors used in this circuit the ordinary polarized electrolytic capacitors you refer to? Is the "bi-directional" (quoted for internet source) capacitor the non polarized electrolytic capacitor you refer to?

 

You can buy a pretty big and pretty expensive 10uF film capacitor that is non-polar if you want.
But two ordinary small polarized 10uF electrolytic capacitors connected back-to-back like I explained will work almost the same.

 

You can buy a pretty big and pretty expensive 10uF film capacitor that is non-polar if you want.

They also make some very large ceramic caps these days if the working voltages are 35V or less. They are non polar and have better frequency response than electrolytics and are cheaper than film caps.