Friday Free Board Quiz – Filtering capacitors Part 3 – Prize is wireless keyboard


KBD-BT2 is wireless keyboard with 2.4ghz USB dongle. It works with all our OLinuXino boards, but should work also with all smart TVs and Linux/Android SBCs.

To participate in the Quiz is enough to re-tweet the Twitter Quiz announcement message.

To double your chances you have to answer the Quiz question :)


We continue to ask about filtering capacitors 🙂 This time you can see C1 and C2 are filtering capacitors with different values connected together. C1 is 100 NF and helps with the high frequencies filtering on the power supply, C2 is with 10 uF and helps with higher current spikes with lower frequency. The picture above is the schematic. The Question is which one of these two capacitors C1 or C2 you should put closer to the IC1 pins?

You have time to re-tweet and/or answer until Monday 9th of November.

In Monday we will post the correct answer and ask to generate random number in range then announce the winner and ship the board by post/airmail.

Good Luck!


8 Comments (+add yours?)

  1. Robert Owen
    Nov 06, 2015 @ 19:32:50

    Smallest value C1 should be closest to VCC pin. Solder directly onto pin underneath board if possible.


  2. Alan Vogel
    Nov 06, 2015 @ 20:40:42

    C1 should be as close to the VCC pin of the IC as possible. If not, then the inductance of the long PCB trace, or wire, to the capacitor can begin to cancel out C1’s capacitance.


  3. Rosen Vuchev
    Nov 06, 2015 @ 22:46:48

    The first C1 cap should be close to the VCC pin for better filterint.


  4. Nebk
    Nov 07, 2015 @ 06:17:54

    The smaller capacitor (C1) should be put closer to the micro because it helps to supply small amounts of power quickly.


  5. Dost Muhammad Shah (@dmsherazi)
    Nov 07, 2015 @ 11:07:06

    C1 should be put closer!


  6. luca
    Nov 07, 2015 @ 15:36:24

    C1 should be closer to the chip!


  7. Brendan Simon
    Nov 08, 2015 @ 02:15:21

    C1 – the lower value capacitor, used to filter high frequency switching transients, should be placed closest to the IC – as close as possible.


  8. Enrico Hartwig (@shudderdev)
    Nov 09, 2015 @ 09:09:34

    C1 has to be closer to the IC


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