SunwayLED        
Results 1 to 5 of 5

Thread: How does reverse polarity protection work?

  1. #1
    Enlightened
    Join Date
    Jun 2008
    Location
    Florida
    Posts
    30

    Thinking How does reverse polarity protection work?

    Was wondering if someone could explain this concept (reverse polarity protection) to me in layman terms?

    For example, I read that if you put the batteries in backwards in a minimag led, the moment you twist it on.......poof?


    I am assuming flashlights without reverse polarity protection are the minority?.....Is this correct?

    Appreciate all the help and info yall can give me!

  2. #2
    *Flashaholic* Marduke's Avatar
    Join Date
    Jun 2007
    Location
    Huntsville, AL
    Posts
    10,110

    Default Re: How does reverse polarity protection work?

    Most reverse polarity protection is a physical ring which allows a positive nipple to contact the board, but won't allow the negative end to touch.

    Most lights have no protection. Don't assume it does unless it explicitly states so.

  3. #3
    *Flashaholic* kramer5150's Avatar
    Join Date
    Sep 2005
    Location
    Palo Alto, CA
    Posts
    6,328

    Default Re: How does reverse polarity protection work?

    As marduke says... usually a ring or raised bumps around the + contact. They prevent electrical contact when the cell is installed backwards. Some DC-DC boards have diodes in line with the +ive input to protect the circuit, they present a Vdrop to the circuit though so a physical type of prevention is better. I always bypass the diodes on my boards to keep the 7135 chips running in regulation for a longer time.
    CLICK HERE for my flashlight reviews.
    PAUL KIM... AN INDUSTRY GENIUS

  4. #4
    Enlightened
    Join Date
    Jun 2008
    Location
    Florida
    Posts
    30

    Default Re: How does reverse polarity protection work?

    appreciate the reply's and apologize for putting the thread on the wrong subforum...

  5. #5

    Default Re: How does reverse polarity protection work?

    You can also use FETs to provide reverse polarity protection with a minimal drop compared to, say, a straight in-line diode.

Posting Permissions

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