NON polarised capacitor - UK Vintage Radio Repair and Restoration Discussion Forum

ekcopyephilips · 16th Feb 2015, 5:58 pm

Hi all

A while ago i found some information (possibly on here) on how to make a polarized capacitor from two electrolytic capacitors.

I have totally forgotten what the article said with regards to values and voltage ratings, could someone enlighten me please?

I need to make a value up to replace a non polarized one on the convergence panel of a Pye 697 chassis.

Sorry to be so thick, but why has the designer chosen to have a non polarized cap ?

Cheers

Mike

ukcol · 16th Feb 2015, 6:21 pm

A common solution when replacing a non polarised electrolytic capacitor was to use 2 polarised ones back-to-back. Each capacitor has to be twice the value of the original and the same working voltage. A better solution is to use a modern non-electrolytic type, at least for values up to about 4.7uF, bigger values tend to be physically too large. I would expect that the designer has specified a non-polarised capacitor because the capacitor in the application is dealing with A.C. voltages that go above and below the zero line.

16th Feb 2015, 5:58 pm	#1
ekcopyephilips Hexode Join Date: Dec 2006 Location: Norwich, Norfolk, UK. Posts: 440	NON polarised capacitor Hi all A while ago i found some information (possibly on here) on how to make a polarized capacitor from two electrolytic capacitors. I have totally forgotten what the article said with regards to values and voltage ratings, could someone enlighten me please? I need to make a value up to replace a non polarized one on the convergence panel of a Pye 697 chassis. Sorry to be so thick, but why has the designer chosen to have a non polarized cap ? Cheers Mike

16th Feb 2015, 6:21 pm	#2
ukcol Rest in Peace Join Date: May 2003 Location: Harlaxton, Lincolnshire, UK. Posts: 3,944	Re: NON polarised capacitor A common solution when replacing a non polarised electrolytic capacitor was to use 2 polarised ones back-to-back. Each capacitor has to be twice the value of the original and the same working voltage. A better solution is to use a modern non-electrolytic type, at least for values up to about 4.7uF, bigger values tend to be physically too large. I would expect that the designer has specified a non-polarised capacitor because the capacitor in the application is dealing with A.C. voltages that go above and below the zero line.