Results 1 to 6 of 6
  1. #1
    Join Date
    Aug 2016
    Location
    USA
    Age
    32
    Posts
    95
    Rep Power
    8

    Do capacitors have a polarity?



    I know that this is a dumb question, but here goes. Basically, my central AC system from the early 2000s has been having a hard time starting up. It used to come on almost instantly, but it recently started struggling to start and browning out the lights for about 1 second when it starts up. However, once the system is running, it runs great. I checked the cap, and it was very corroded. I installed a new capacitor, and the unit starts up instantly again. The cap for the indoor blower motor seems weak too, so I went back to that HVAC shop to get a new cap for that too, and the guy warned me that they have a polarity, and the cap may work fine if connected backwards for a little while, but it can explode and start a fire with no warning. That doesn’t sound right to me, but I’m far from an expert. I thought that AC caps don’t have a polarity since the current alternates anyway, hence the name “AC”. Could someone please verify that the capacitors don’t have a polarity? Thanks, I just want to make sure that I didn’t screw up.



  2. #2
    Join Date
    Sep 2003
    Location
    ISRAEL
    Age
    72
    Posts
    4,266
    Rep Power
    46

    Re: Do capacitors have a polarity?

    Capacitors used in electronic have polarity.
    The capacitors we use in AC&R do not have polarity.

  3. #3
    Join Date
    Aug 2016
    Location
    USA
    Age
    32
    Posts
    95
    Rep Power
    8

    Re: Do capacitors have a polarity?

    Quote Originally Posted by chemi-cool View Post
    Capacitors used in electronic have polarity.
    The capacitors we use in AC&R do not have polarity.
    My understanding is that AC capacitors don’t have a polarity since AC alternates, but DC capacitors have a positive and negative. Is that correct?

  4. #4
    Brian_UK's Avatar
    Brian_UK is offline Moderator I am starting to push the Mods: of RE Site Moderator : and general nice guy
    Join Date
    Mar 2001
    Location
    Dorset
    Age
    76
    Posts
    11,192
    Rep Power
    60

    Re: Do capacitors have a polarity?

    That's what he said, electronics are DC.
    Brian - Newton Abbot, Devon, UK
    Retired March 2015

  5. #5
    Join Date
    Aug 2006
    Location
    england
    Age
    49
    Posts
    3,874
    Rep Power
    46

    Re: Do capacitors have a polarity?

    The HVAC shop guy is either lying to you or is incompetent.
    Mostly found in Oxfordshire, UK :)

  6. #6
    Join Date
    Feb 2009
    Location
    telford
    Posts
    2,097
    Rep Power
    33

    Re: Do capacitors have a polarity?

    Only ever witnessed one explode wow how do they get all that stuff in a small tube

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •