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I have come across some old capacitors and would like to use them if possible, but I'm not sure how to determine their values from the markings on the sides. I understand there is some convention to these markings, but have not been able to decipher it. Can anyone tell me the values of these three capacitors, I would appreciate if someone could break out what the various parts of the names indicate? I believe they are all ceramic.

1) Good sized disk. Labeled E N750 10J.

2) Square. Labeled CK05 BX 104K 50V K 8514. This one I could kind of decifer as 10^4=100000pF=100nF +/- 10%, max input voltage of 50V, not sure if the other numbers mean anything.

3) Tiny blue one. Labeled 104 25E 8720. I'm guessing the 104 also means 100000pf.

Also, are any issues expected when using old ceramic capacitors?

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    \$\begingroup\$ How much would you be paying for brand new 100 nF capacitors? \$\endgroup\$ – Andy aka Apr 5 '17 at 14:19
  • \$\begingroup\$ @Andyaka Not much, but I'd like to understand what I have. \$\endgroup\$ – denver Apr 5 '17 at 14:27
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    \$\begingroup\$ What you have are capacitors (hopefully) with an unknown history that may or may not be degraded and may or may not conform to some identification rules. How much do you value your time? I know what I'd do with them. \$\endgroup\$ – Andy aka Apr 5 '17 at 14:30
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    \$\begingroup\$ @Andyaka Point taken. Regardless of it I use them or not I would like to understand them. (not that it is relevant, but I do know their history) \$\endgroup\$ – denver Apr 5 '17 at 14:37
  • \$\begingroup\$ These sound like old monolithic ceramic caps I used to use in 70's and 80's. 1st one could be for low RF and N750 often meant neg -750 ppm/'C used to some temperature compensation with old Oscillator designs although P150 was more useful and NP"zero" but said as NP"oh"= NP0 aka C0G were best with low ESR and <50ppm/'C (lowest tempco range). I agree with Andy use 2,3 as general purpose decoupling caps, in case you are desperate. Ceramic caps now are usually multi-layer and not monolithic. \$\endgroup\$ – Sunnyskyguy EE75 Apr 5 '17 at 14:37
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These sound like old monolithic ceramic caps I used to use in 70's and 80's. 1st one could be for low RF and N750 often meant neg -750 ppm/'C used to some temperature compensation with old Oscillator designs although P150 was more useful and NP"zero" but said as NP"oh"= NP0 aka C0G were best with low ESR and <50ppm/'C (lowest tempco range).

I agree with Andy use 2,3 as general purpose decoupling caps, in case you are desperate. Ceramic caps now are usually multi-layer and not monolithic.

MLCC caps became replacements for Kemet family of monolithic caps. The tiny blue one may be MLCC type. Multi-Layer Ceramic Capacitor,

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