Capacitor voltage rating with rectifier

Discussion in 'General Electronics Chat' started by mendiola_loyola, Nov 12, 2010.

  1. mendiola_loyola

    Thread Starter New Member

    Sep 18, 2010
    16
    0
    Dear All:

    I'm rectifying a 12V rms AC voltage using a diode bridge.

    I want to know how to calculate the capacitor voltage rating.

    Do I have to multiply 12 * 1.5 or 12*2 ?

    Thanks.
    Alfredo Mendiola Loyola
    Lima, Perú
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    The multiplier to go from RMS to peak is 1.404. The voltage on the caps will be a bit less, due to the conduction drops across the diodes. For a good safety margin, use a capacitor voltage rating of about double the calculated voltage.

    So, 12 VRMS * 1.404 = 16.85 VDC. Use a capacitor rated for 35 volts.
     
  3. mendiola_loyola

    Thread Starter New Member

    Sep 18, 2010
    16
    0
    Thank you for your Help

    Alfredo Mendiola Loyola
    Lima, Perú
     
  4. BillB3857

    Senior Member

    Feb 28, 2009
    2,400
    348

    Hey Beenthere,

    When did they change the value of the square root of two? :eek: I missed it. How do I update the programming on my TI calculator?:confused:

    Just kidding of course. My fat fingers frequently get me, too. At least yours are consistent.
     
  5. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Wow, I've been dropping the 1 out of the value for years. For the record, it's 1.4142136 on my TI.

    Let's see, that's 16.97 volts.
     
  6. BillB3857

    Senior Member

    Feb 28, 2009
    2,400
    348
    Olde age tends to let us lock in pre-conceived notions. From your avitar, I can only guess tht I have a couple of years head start on you.
     
Loading...