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About Capacitor Coding

By on October 7, 2008

 polyester cap

I got an email that asked what is the meaning of the first two code of a polyester (mlyar) capacitor. Here is the question:

“Hi Jestine! Hope your doing fine. I just want to ask these question.
Some polyester film (mylar) capacitors have code markings like these: 2A102K
No doubt that this has a value of  .001uF with a tolerance of +10%. What I need to know
is what does 2A stands for? Is it voltage rating? Others begin with 1H, 2B, 2D,
2E, 2F, 2G, 3A, 3C, etc. Please provide me some data regarding these. Thanks.”

I used to ignore the first two codes as normally it would be in the 50 volts rating and i only calculate the capacitance and the tolerance. Since there are so many different number in the first two numbers, i guess it could be some meaning behind it. From search engine i could not  locate any data about it. If you know what the first two numbers stand for please give a comment- thanks in advance!



  1. Brian Clark

    December 7, 2008 at 7:10 am

    The code is the voltage rating:

    These list the voltage codes from 50V to 630V:
    1H = 50V
    2A = 100V
    2D = 200V
    2E = 250V
    2G = 400V
    2J = 630V

    Love your website - lots of wonderful information!!

    Brian Clark
    Norfolk, Virginia, USA

    • sanjeev patel

      April 11, 2014 at 1:19 am

      and 2T=150v

    • Krishna

      October 15, 2017 at 12:35 pm

      Nicely explained thanx

  2. admin

    December 9, 2008 at 7:57 pm

    Hi Brian,

    Thanks for sharing and have a great day to you.


  3. J.DamZamang Samte

    February 20, 2016 at 9:50 pm

    In a polyester capacitor there are about 6 character.what does the last character stands for. Eg.k or j.

    • Jestine Yong

      February 22, 2016 at 3:53 am

      Hi J.Damzamang,

      K means 10% and J means 5 % tolerance.


  4. J.DamZamang Samte

    February 20, 2016 at 9:55 pm

    Moreover, I would like to ask is that,is the body color had a meaning/value? Coz. there are green, red or yellowish red. I would be very greatful if I was answered.

    • Jestine Yong

      February 22, 2016 at 3:54 am

      Hi J.Damzamang,

      Usually no. The color used always depends on the manufacturers. Different manufacturers will produce different colors.


  5. Debug

    March 7, 2017 at 5:30 pm


    The capacitors in my hand having 7 letters like p2j472k. I understand from the above replys that 2j=630v 472=4700pf and k=10% tolerence. Is there eny significance to the P at starting?

    • Jestine Yong

      March 9, 2017 at 9:27 pm

      Hi Debug,

      Good question but sorry i do not have the info for the letter P in front. The three specs you have mentioned are the most important specs when looking at capacitor data.


  6. moda1560

    June 7, 2017 at 11:11 am

    Hi there!

    what about the following caps?

    Tk473 | Tk183K. => Tk = xxx Volts?
    T2n7J. => T = xxx Volts?
    8C104K | 8C823K | 8C563K | 8C103K | 8C272K. => 8C = xxx Volts?
    3A103J | 3A472J | 3A222J | 3A102J | 3A51n0J. => 3A = xxx Volts?

    they're polyester film capacitors and green like the Image.

    I have them all, but I don't know the working voltage (WV)?!


    • Jestine Yong

      June 26, 2017 at 10:53 pm

      Hi Moda1560,

      The front code is manufacturer's code. Take a look at this link


    • maurizio

      March 21, 2021 at 4:24 pm

      1H: 50V
      2A: 100V
      2B: 125V
      2D: 200V
      2E: 250V
      2G: 400V
      2J: 630V
      2K: 800V
      3A: 1000V

  7. Misheck

    June 20, 2021 at 6:00 pm

    How do you tell a mlyar capacitor is damaged.

    • Jestine Yong

      June 23, 2021 at 11:10 am

      Hi Misheck,

      Made sure there is no crack in the capacitor and test the capacitor value with digital capacitance meter. You can also check for shorting using resistance test. For more info on how to test and check electronics components like a professional you can check out this ebook.



  8. Manish P

    August 7, 2022 at 2:01 am

    my one is having D334k2I code what is volt and Joule rating of it.


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