Selecting capacitor values

Discussion in 'General Electronics Chat' started by shortbus, Mar 6, 2010.

  1. shortbus

    Thread Starter AAC Fanatic!

    Sep 30, 2009
    hobbyist, thanks again. Do you have anything on choosing a capacitor value? I don't have a circuit in mind. Just a general rule of how to pick values, then refine from there.

    This is the practical hands on stuff I've been looking for. It's hard learning this on your own, and books don't give practical/usable info.

    Thanks again.
  2. beenthere

    Retired Moderator

    Apr 20, 2004
  3. Wendy


    Mar 24, 2008
    The thing about picking parts is it isn't as important as you think. Sometimes it is critical, if you are feeding a 50Ω impedance (RF) or a 600Ω audio line then that will set the standard, but after that a wide range of values will work.

    There are several questions you ask yourself when you are selecting a component, what is too much, and what will it do to my circuit? What is too little, and what will it do to my circuit? This applies for all component, not just caps or resistors. Pick a transistor whose voltage ranges are too small, or wattage is too small, and it will fry. In this math is your friend.

    After establishing what is too much or too little then pick a middle ground, and look at what it does. Does it force another part to be too much or too little (a common problem with filters). Don't assume, do the math. When everything is balanced then try building the design. If it fails then analyze why.

    One of the reasons old techs and old engineers make it look so easy is they have seen a lot of failure modes. There is an old expression, you learn more from your failures than your successes. This is true.

    One way to get experience is to jump in there, and fail every so often pushing your personal envelope.
  4. hobbyist

    Distinguished Member

    Aug 10, 2008

    Please don't get me wrong,
    I really appreciate all the nice comments people gave me on that thread,

    But I do agree with "Beenthere", that thread is sticky'd for a subject learning purpose, and if it continues, as a open thread, then the purpose for it being sticky'd will get lost in the shuffle"

    The only reason I kept adding to that thread is I felt I needed to show the courtesy of replying back to the people who were asking questions to me,
    otherwise I would not have added to the thread.