is there a difference between dc capacitor and ac capacitor?

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1

is there a difference between dc capacitor and ac capacitor or i can use any capacitor for both dc and ac application.
dc-12v
ac-220v ,50 hz

2

DC capacitors can explode if you connect them to AC

ac-220v ,50 hz

a) Never, ever, EVER connect a capacitor to AC 220V unless it has a "Y" rating. They're usually blue and definitely don't have any polarity markings.

b) If you don't know if a capacitor has a Y rating then don't connect it to mains electricity.

There are NO exceptions to rules (a) and (b).

3

Yes.

Above rules are good. Something things to note:
Some caps, mainly Tantalum and Electrolytic, are rated for voltages in only one direction (unipolar). These you should never use for AC applications where the voltage can drop below 0V for very long (small impulses can be expected, though using a bipolar cap to absorb them is probably a good idea). These are ones with polarity markings. When used wrong they will act as a short and often explode or burn up, and do not use one that has had a reverse voltage applied, since it might have fused inside and now just be a short. However, if you are rectifying an AC signal, so that it will always be positive, then you can use one of these safely. However, if you connect it backwards, it will probably explode.

Other caps usually are rated for AC and DC applications. Their allowable voltage ratings will often be different for AC vs DC. When choosing a cap, It is recommended giving yourself at least a 100% margin from what you expect your voltages to be.

4

i tried it hard with the shopkeeper to know whether the capacitor is y rated but it seems like he just does not know anything about his products. anyways i brought this 100nf 400v capacitor with no polarity marking, will this work?
image given
model no -100k400

DSC_0135.jpg
DSC_0135.jpg1944×2592 1.14 MB

5

zacmackra:
i tried it hard with the shopkeeper to know whether the capacitor is y rated but it seems like he just does not know anything about his products. anyways i brought this 100nf 400v capacitor with no polarity marking, will this work?
image given
model no -100k400

Looks like polyester.

It's unlikely to burn/explode but 600V would be a better choice if he has them.