What type of capacitor is this?

[Adnan68]

Hello all,

I know this is 1uF, 250VAC cap but not sure what type it is. All I can find to replace it are film type. I have attached some pictures. Thanks.

[mariushm]

Re: What type of capacitor is this?

Polyester or polypropylene , you'll find them in the Film Capacitors on Digikey:

http://www.digikey.com/product-searc...acitors/131088

I'm not sure it's a 0.1uF though.

[selldoor]

Re: What type of capacitor is this?

I would have thought 1.0k was 1000pf = 1nf

[PeteS in CA]

Re: What type of capacitor is this?

"K" may mean 10% tolerance. Or perhaps "Y/J" means it's a Y cap, 5% tolerance (and 1000pF). Does the other side of the cap have a bunch of safety agency approval marks? 1uF is a reasonably common X cap value, but would be pretty large, physically. 1000pF is a reasonable and common Y cap value, (2200pF, 3300pF, and 4700pF might be slightly more common). Was one of the leads connected to chassis (through a trace to a mounting hole)? If so, that would be a Y cap; the highest value Y cap I've ever seen was .047uF, so if it's a Y cap, the value probably was 1000pF.

[budm]

Re: What type of capacitor is this?

It sure looks like Y cap with 250VAC rating, 1000pF (.001uf) is about right, 0.1uf will be way too much current in the safety ground.

[PeteS in CA]

Re: What type of capacitor is this?

Adnan didn't say where the part came from, though the lead length and residual solder pattern on the leads tells me it was on a PCB. So probably from something electronic (as opposed to home appliances, HVAC, or industrial machinery). In electronics, a 250V AC voltage rating usually means a line-line or line-ground capacitor, which very commonly have lots of safety agency approval markings. On another tack, a 1uF X cap is going to be much larger than a 1000pf (.001uF) Y cap. I'd love to see a pic of the cap next to a ruler, showing the other side of the part.

I think safety regs' leakage current limits relegate usage of Y caps larger than 4700pF to special applications (hard-wired power, possibly?). 4700pF is probably the limit for cumulative Y capacitance: e.g., if you have three Y caps on Line (and/or Neutral), two 2200pF and one 1000pF, the leakage current will probably be too high. The power line filters in which I used .022uF Y caps (Rifa PME271 series) were used in hard-wire installed computer equipment.