1

So I need a 1uf non-polarized electrolytic capacitor for a circuit I found. But I don't have one. I found on the internet that you can make one by placing 2 caps with the same value and the same polarities touching each other (pos-neg-neg-pos or neg-pos-pos-neg) and the total capacitance will be half of the capacitance of one of them. So I figured I need 2 2uf caps, but I don't have those either :(. Can I make one with different caps values? Like a 68uf cap placed in series with a 2.2 uf cap makes a 0.9uf cap which is close enough. Thanks!

Abdullah Alwakeel
  • 51
  • 1
  • 1
  • 3
  • Reading [this answer](http://electronics.stackexchange.com/a/21932/104387) I think that it's possible. "*When voltage is applied, the correct-polarity capacitor gets the full voltage.*" Then you should take care about voltage. – Antonio Sep 05 '16 at 14:34

1 Answers1

2

You can do something like this:

schematic

simulate this circuit – Schematic created using CircuitLab

Not all electrolytes will withstand the 0.7V reverse voltage: wet aluminum electrolytes should withstand at least -1V, do not try with tantalum capacitors. You can use Schottky diodes to get lower drop if you have some at hand.

Note that if C1 and C2 are different then this circuit will have capacity of C1 on one polarity and C2 on the other.

student
  • 541
  • 3
  • 12
  • What if this circuit would be used in a filter? I can imagine it would not work as expected, as the capacity varies depending on the voltage. – Botnic Sep 05 '16 at 14:54
  • True. I have edited the answer to point that out. – student Sep 05 '16 at 15:01