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About Electrolytic Capacitor Value

By on November 24, 2009

 filter cap

Have you ever came across electrolytic capacitor value that you can’t get from the market? The situation may be that you can get the exact cap value from the market but it was just not worth it to purposely drive to down and buy the exact cap value. Let’s take this for example, in LCD Monitor repair, many of the main filter cap rated from 68 uf to 120 uf with 400 to 450 volt. In some cases like when i could not get the 120uf 400 volt cap, i would just install a 100uf 400 volt cap as replacement. The result was-the LCD Monitor still could work well without problem. Similarly if you can’t get a 68uf cap, you can always use a 100Uf e-cap for replacement.

A slight different in capacitance value for the main cap is acceptable. If you are replacing cap in the frequency circuit, then the value have to be the same regardless what cap it is.



  1. Namal Vaas

    November 30, 2009 at 7:11 pm

    Hi sir thank you for sending these details I'm Still satudtying. Sir can you send me readings of the component(multy meter readings)

  2. admin

    December 1, 2009 at 8:05 am

    Hi Namal,

    All these i have compiled into an ebook


  3. Franco

    December 9, 2009 at 9:27 pm

    Dear Admin,

    I found only now Your great website , thanks alot to you and all the fellows tech. That fill own problem on your website.

    My adventure start 2 months ago, I have a TDS scope TEK model 420, well in short the problem is present only in standby mode, you can heard a tick, tick and tick every second, but if you turn on the scope all it works fine.

    I take the power supply and put on my desk, with a simulated load for 5 Vcc on main power output, and I have replaced all caps ìn the pcb, only the 2 main caps input on 220Vca ,I do not change.

    After that the tick stay there, I have checked also the diode regulator but all seems ok.

    I checked the kickstart circuit but seems to work.

    The only strange things that I note is that in standby mode the UC3884, on pin 7 I found 12 Vcc with a 2 volt ripple, it take the power supply thru a resistor connected on the main rectifier, but main cap the 2 680hU 400v seems ok.

    Also the signal on the 2 gate mosfet , isolated by a transformer, arrived a tick.

    I am not able to find a spare part, and need to repair.

    All suggestion are welcome.


  4. admin

    December 10, 2009 at 2:22 pm

    Hi Franco,

    Is all the output voltages from the SMPS good/stable?


  5. brian sammut

    December 16, 2009 at 4:52 pm

    we order buy mistake the e-book testing electronic compoments because we didin't notice that it was a e-book we was looking for a normal book,so if is not possible we are asking for our money back.

    thanks from your friend brian hope i hear from you soon .

  6. admin

    December 16, 2009 at 9:32 pm

    Hi Brian,

    The website clearly stated that it is an ebook and not a hard copy book. Please refer to the refund policy:

    All my buyers bought my ebook and print out the information. When they have question, they will email me for support. It is the information inside that counts. You can have a 1000 pages in a hard copy book but most of it are theories.


  7. Amir Mukhtar

    November 3, 2011 at 9:15 am

    Sir Jestine
    Assalam Alaikum
    Greetings to you and your whole family from me.
    ACtually, Capacitor is an important component in electronic circuit because, capacitor provides filtering in circuits in general and balancing in particular. Like-Wise, Capacitor use in power supplies for filteration. But mostly uses in other circuits for frequency and clamping control as usual. Capacitor is also used in Patriot defence system circuitry for Low and high pass filters which not detection of enemy but it also hit as per programmed functions.

    thanks you
    yours student
    Amir MUkhtar

  8. admin

    November 4, 2011 at 7:54 am

    HI Amir,

    Thanks for your comment.



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