UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Capacitor voltage ratings: AC / DC / dual

The_Archiver · 12th Apr 2021, 5:41 pm

Hello, all. This query is related to ongoing efforts to repair a Philips N1500 (please see separate thread if interested).

The attachments which are from a section of that VCR’s Service Manual show that the polyester caps are rated at 250V, but is that a reference to AC or DC? As there are no value markings on the existing polyester caps, only colour coding, and not wanting to order new for old replacements of the wrong rating and possibly cause irreparable damage, can anyone please advise as to what ratings should be ordered?

Having looked on the RS Components website, almost all of the capacitance values needed are available, but even some of the voltage ratings on the polyester caps there are confusing me further: some have AC only rating, some DC only rating, and some dual rating. If the general rule (correct?) is that DC peak voltage is AC*sqrt2, should a polyester cap rated at a DC maximum voltage of 250V suffice? Similar solution for the ceramic caps rated at 500V(DC?)...?

This may be an easy concept to grasp for some, but am having difficulty understanding even basic information nowadays for whatever reason/s.

Thanks in advance.

Philip

12th Apr 2021, 5:41 pm	#1
The_Archiver Pentode Join Date: Dec 2008 Location: Thurso, Caithness Posts: 118	Capacitor voltage ratings: AC / DC / dual Hello, all. This query is related to ongoing efforts to repair a Philips N1500 (please see separate thread if interested). The attachments which are from a section of that VCR’s Service Manual show that the polyester caps are rated at 250V, but is that a reference to AC or DC? As there are no value markings on the existing polyester caps, only colour coding, and not wanting to order new for old replacements of the wrong rating and possibly cause irreparable damage, can anyone please advise as to what ratings should be ordered? Having looked on the RS Components website, almost all of the capacitance values needed are available, but even some of the voltage ratings on the polyester caps there are confusing me further: some have AC only rating, some DC only rating, and some dual rating. If the general rule (correct?) is that DC peak voltage is AC*sqrt2, should a polyester cap rated at a DC maximum voltage of 250V suffice? Similar solution for the ceramic caps rated at 500V(DC?)...? This may be an easy concept to grasp for some, but am having difficulty understanding even basic information nowadays for whatever reason/s. Thanks in advance. Philip Attached Thumbnails