The capacitance of capacitor and energy.

Discussion in 'General Electronics Chat' started by TAKYMOUNIR, May 27, 2015.

  1. TAKYMOUNIR

    Thread Starter Active Member

    Jun 23, 2008
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    If the capacitor has 100 v limit and its capacitance is 1uF ,this mean that the max. energy is 1/2CV*2=5 m J
    or I can put more energy on the cap.
     
    Last edited: May 28, 2015
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    milli G ????

    0.5mJ is all you can put in it...
     
  3. ian field

    Distinguished Member

    Oct 27, 2012
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    You can't even cheat with electrolytics - if you supply a current limited higher voltage just under the critical leakage point, the oxide dielectric will form thicker to withstand a higher voltage - but the effectively greater spacing between the plates results in proportionately lower capacitance.
     
  4. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    If this is a real world capacitor don't put 100V across it, not if you want the cap to survive for the long term.

    75V is better. I would limit it to 50V.
     
  5. ian field

    Distinguished Member

    Oct 27, 2012
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    If its an electrolytic; the applied voltage is what keeps it formed, at a lower voltage the electrolyte very slowly etches away the oxide dielectric - if you then suddenly apply the full rated voltage without first re-forming the capacitor, it'll probably break down.

    As a result of the oxide dielectric getting thinner, the capacitance increases.

    If the TS is going to the trouble of calculating the energy for a given voltage/capacitance, the exact value of capacitance may be important.
     
  6. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    Without parentheses, it is easy to misinterpret your equation. I am assuming that you mean \frac{1}{2}CV^{2}

    I get 5 mJ

    My work is shown below...

    10^{-6}*10^{4}*\ .5=.005J\ or\ 5mJ
     
  7. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Yep...
     
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