How to read SMD capacitor codes

Passives Capacitors
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1

I have a capacitor with 3 lines that reads:
Line 1: 0eK
Line 2: 100
Line 3: 25v
There is a rectangle like symbol before the lettering in line 1.

And another that reads:
Line 1: 0K
Line 2: 22
Line 3: 16v
There is a rectangle like symbol before the lettering in line 1 and another hard to read symbol at the end.

I also have a radial capacitor that reads: 2.2uF63v.

Do I basically have (1) 100uF / 25v, (2) 22uF / 16v, and (3) 2.2uF / 63v capacitors? Do I simply need to be concerned with lines 2-3? What about tolerance or ripple current? I want to replace them with tantalum capacitors but I can’t get past the initial identification. There are so many to choose from.

2

The basic descriptions you’ve come up with are what I’d infer from the info given. To a first approximation, capacitance value and voltage rating are the first things you’d want to match, along with basic capacitor type. (aluminum or tantalum electrolytic, ceramic, film, etc.) Physical dimensions are another characteristic that’s helpful in figuring out what it is that one’s trying to replace.

There are some circumstances where the finer details matter, others not so much. One really needs a sense of what the part is doing and why it was chosen in the first place to make a call on what’s likely to be important.

3

You are correct.

4

Should I be concerned about 10% or 20% tolerance? I heard if it isn’t shown you assume 20%. Would 10% be better than 20%?

5

Strictly speaking? Yes.

But if you don’t need the precision you are likely fine with a 20% piece. How sensitive is your use case?

6

Don’t know. It’s for a car climate control module that died.

7

Can I replace these aluminum electrolytic capacitors with ceramic? I want something more reliable and it’s for a climate control module in a car. I may just go with the aluminum electrolytic for the price but it would be nice to know for future reference. I thought about tantalum but I heard they can catch fire. thanks

  1. 493-9370-1-ND (CAP ALUM 100UF 20% 25V SMD) with 565-4677-1-ND (CAP CER 100UF 25V X7R SMD)

  2. 493-9413-1-ND (CAP ALUM 22UF 20% 16V SMD) with 490-16629-1-ND (CAP CER 22UF 35V X7R SMD)

  3. 732-8967-1-ND (CAP ALUM 2.2UF 20% 63V RADIAL) with 445-173118-1-ND (CAP CER 2.2UF 100V X7R RADIAL)

8

I wouldn’t bother, but its your $ and your call. An dirty secret about ceramic caps of the sort mentioned is that their capacitance value tends to drop off sharply with applied DC voltage, and also vary pretty significantly with temperature.

Buy yourself some aluminums that match your values, fit, and have a decent “Lifetime@Temp” rating, understanding that actual values roughly double with each 10°C decrease in temp; 10K hours @ 115°C is more or less equivalent to 20K hours @ 105°C, for example. Neither would last anywhere near those figures if the original part failed due to some external factor that’s left uncorrected.

And yes, some tantalums do have an incendiary failure mode. You can read about these and other capacitor selection criteria at some length here.

9

ok, I ended ordering the both aluminum polymer and electrolytic caps with decent lifetime ratings. I didn’t know if the original are polymer or electrolytic. I would have thought electrolytics have vents on top but many pictures show they don’t so I would have both available in either case.