555 astable w/non-polarized timing cap?

Question

Newbie question. just ordered a few components from Digikey, one of which was a non-polarized smt ceramic chip cap: CAP 4.7uF 10V CERAMIC X5R 1206 i'm using it in a typical astable 555 timer circuit...with a diode across R2 for duty cycles

Spehro Pefhany · Accepted Answer

No, it will work fine. The polarized bit is a limitation of thecapacitor, not a requirement of the circuit. Best regards, Spehro Pefhany-- "it's the network..."                          "The Journey is the reward"             Info for manufacturers:  software/hardware/analog  Info for designers:

John Woodgate · Answer

I read in  that Leon Sorokin wrote (in ) about '555 astable w/non-polarized timing cap?', on Sat, 18 Dec 2004:You can always replace polarized caps by non-polarized (unless thedesign is VERY flaky and depends on leakage current).-- Regards, John Woodgate, OOO - Own Opinions Only. The good news is that nothing is compulsory.The bad news is that everything is prohibited. Also see

w_tom · Answer

Supplemental information - critical parameter especiallywith low power 555's is capacitor leakage current.  Tantalumcapacitors were preferred over aluminum electrolytics. Leakage in a ceramic capacitor should be so small as to beirrelevant.Le

Leon Sorokin · Answer

thanks guys,

Arthur W. · Answer

The only advantage of a polarized capacitor is size. In other words polarized capacitors such as electrolytics and tantalums have a higher capacitance/volume ratio for a given voltage. However non-polarized ceramics would be preferred since they have better electrical properties. The X7R implies a relatively high temperature characteristic versus a type called NPO which has a much lower temperature characteristic. Never-the-less unless you are looking for precision and stability  better than 10% or so you will be fine.

555 astable w/non-polarized timing cap?

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