Series Capacitor calculations

Discussion in 'Homework Help' started by gilbey, Jan 9, 2006.

  1. gilbey

    Thread Starter New Member

    Jan 9, 2006
    Really hope someone can help me here!

    I'm really struggling to understand the formulae used to express the capacitance or resistance of series capacitors or parallel resistors. I know it must be really simple but i just cannot understand how the text books get to the final figures!

    Say for instance you had 2 capacitors wired in series that were 10 μ F & 20 μ F how do i find the total capacitance for the circuit.

    Please help this is driving me insane, i keep just staring at the formulae feeling pretty dumb.

  2. pebe

    AAC Fanatic!

    Oct 11, 2004
    The formula for series capacitors is
    1/Ctot = 1/C1 + 1/C2 + 1/C3 ....etc where Ctot is the total value.

    In your case 1/C1+1/C2 becomes 1/10+1/20 which equals 3/20 . So Ctot = 20/3 = 6.66uF

    Resistors in parallel use the same formula - just replace C with R.
  3. gilbey

    Thread Starter New Member

    Jan 9, 2006
    thank you, i knew it was simple but for some reason it just wouldn't sink in
  4. mikeakarobinhood

    New Member

    Mar 6, 2008
    mad, thanx! my engineering test is tomorrow and this thread helped alot, its the only place i could find the capacitor formula in series. i registered just to say thanx, ill probly be on here alot more often now. ty:):):)
  5. hgmjr

    Retired Moderator

    Jan 28, 2005