Should a Bridge Rectifier read 0 Ohms in any direction?

Discussion in 'General Electronics Chat' started by Fred1451, Oct 3, 2012.

  1. Fred1451

    Thread Starter New Member

    Oct 3, 2012
    2
    0
    I have a piece of equipment that is tripping breakers as soon as it is turned on. I was pointed to a bridge rectirfier as the probably cause of my problems. My meter does not have a diode test function so I tried reading resistance. I have opens between every pin except between the '+' DC pin and one of the AC pins. Is that supposed to be there, or have I found my problem?

    Thanks.
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,647
    2,346
    Hello,

    Have you taken the bridge rectifier out of the circuit?
    If the bridge rectifier is still in the circuit the transformer will measure like an almost short.
    Take a look at this page how to measure diodes with a DMM:
    http://www.allaboutcircuits.com/vol_3/chpt_3/2.html

    Bertus
     
  3. vk6zgo

    Active Member

    Jul 21, 2012
    677
    85
    You may also find it helpful to read this thread on p2 of this forum:-
    Full bridge rectifier

    P.S On second thoughts,you probably have found your culprit.
    In a normal circuit using a transformer,there will be a short between the two AC inputs,but there should not be one between either of the AC inputs & the positive output.
    The bad news is,that if you have AC on that rail,you may have killed some components.

    Thanks for the link,Bertus.
     
    Last edited: Oct 3, 2012
  4. Fred1451

    Thread Starter New Member

    Oct 3, 2012
    2
    0
    I had the bridge completly out of the machine.
     
  5. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,386
    1,605
    It's worst then that, he's dead, Jim.
     
  6. ramancini8

    Member

    Jul 18, 2012
    442
    118
    Check for a shorted filter capacitor or you might blow another diode bridge when you fire it up.
     
Loading...