Metallized Polycarbonated film capacitors

[fuseshut]

I am searching for the above capacitors. the application is a snubber network across a teccor/littlefuse triac. The value of the capacitor is .1uF, 400V rated if possible, surface mount preferably. I have looked at Vishay, Digikey.
First of all, do I have to go with metallized polycarbonated film for snubber network across triac.
Second of all, if not what other material could I use? Ceramic? Not sure what the characteristic difference might be?

 

[pstuckey]

What is your temperature range, and tolerance across temp?

Metallized polycarbonate have very good tolerance across their whole temp. range. Ceramic (NPO) can also have very good temp response, but finding an NPO at 400 VDC, 0.1 uF might be tough.

It looks like Vishay 632P series meet your requirements, but they are leaded not surface mount.

Peter

 

[VisiGoth]

I was very happy with a custom puchase of an Illinois Capacitor similar item (1kv leaded) some years back. It had enough capacitance at -20C so the variation with temperature was tolerable for us.

 

[ScottyUK]

Metallised polypropylene film (MKP) is a fairly typical choice for snubbers in high energy systems. MKP has excellent pulse response and is available in high voltage, high current designs. Often the designs are self-healing which improves their survivability on the mains system. I've had good results from Evox-Rifa and ICAR for snubber applications on high power (MW-level) controlled rectifiers.


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One day my ship will come in.
But with my luck, I'll be at the airport!

 

[CarlPugh]

It appears that in this application you will have AC across the capacitor.

IF THERE IS 115 VOLT AC ON A CAPACITOR, THE CAPACITOR MUST BE RATED FOR AC APPLICATION.

My experience is that capacitors that are rated for 400 VDC and are used at 115 VAC will have a life of a few minutes to a few hours.

 

[ScottyUK]

Carl raises an good point.

In Europe, mains-rated capacitors in small sizes tend to be marked Class X, X2, or Y according to their application. For your application it will be marked Class X or X2; Class Y types are primarily for applications connecting a line or neutral to earth (e.g. filtering).


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One day my ship will come in.
But with my luck, I'll be at the airport!