Electronic – Tantalum Cap Code Explained

capacitorcodecomponent-valuescomponentsidentification

I need to replace the following cap:

enter image description here

It was placed at the input of a device that runs off 24Vdc, like the following schematic.

schematic

simulate this circuit – Schematic created using CircuitLab

I'm repairing the unit after an explotion due to a maintenance where the board was fed 220Vac instead of 24Vdc…
Bottom line, while repairing the unit i found this Cap (C1) shorted and i need to replace it, but i've never seen a tantalum cap with this markings.

Of course, it's a 47uF cap, but the rest of the data i ignore.

I assumed that K is for tolerance (10%), and 20 for 20V, but this makes no sense in a circuit that runs on 24Vdc, so i need to find out the voltage rating of this cap (sure, i could simply replace it with a 40V and be safe, but i want to leave things as original as possible, and also want to learn to read this codes, it will become usefull in the future…)

So, could you fill the next list and perhaps explain how this code is selected?

R+: ?

476: 47uF

20K: ?

633: ?

Best Answer

Here is what I found after doing a quick search online:

enter image description here

Furthermore, you can look at the following link to find more information about their device marking and the R+ at the top of the Capacitor.

Kemet Capacitor Marking

Initially, what threw me off was the date code located at the bottom. I thought this would represent the ESR (Equivalent series resistance) of the capacitor.

In the end, it seems like the capacitor is rated for 20V which makes very little sense for the application you have at hand. Therefore, it would probably be a good idea to review the design and possibly thinking about adding some Galvanic isolation to prevent further damage to the system due to ESD.

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