Connect with us

Circuit problem

Discussion in 'General Electronics Discussion' started by tenmen, Oct 5, 2012.

  1. tenmen

    tenmen

    13
    0
    Oct 5, 2012
    Can anyone help me, Im trying to build a small 12v portable supply which is recharable, my problem is identifying how to connect it up so I have a flashing LED when connected to AC.
     
  2. davenn

    davenn Moderator

    13,249
    1,746
    Sep 5, 2009
    hi tenmen
    welcome to the forums :)

    OK draw out and post what you have already and then we can go from there :)

    There are flashing LED's available that along with a current limiting resistor could
    be placed across the DC input to the charging cct

    Dave
     
    Last edited: Oct 6, 2012
  3. tenmen

    tenmen

    13
    0
    Oct 5, 2012
    What I have is a 12v rechargable battery, this is connected to a cigarette socket and a rocker switch to turn the unit on.

    I have a 500Ma trickle charge which plugs into a mains supply for re-charging the unit, the 12v battery is directly connect to the jack plug socket so it can be charged, is it possible to include a flashing LED which will illuminate only when connected to mains supply and not the 12v battery.

    Any help or advice will be much appriceated.

    Regards
     
  4. donkey

    donkey

    1,286
    56
    Feb 26, 2011
    [​IMG]
    the easy way of doing it is to run an LED accross the 2 pins with a diode to stop it detecting the battery itself. I hope someone can correct me if I am wrong
    if you use the same jack for both the car lighter as you do for the mains then this won't work
     
  5. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

    8,393
    1,266
    Nov 28, 2011
    What type of battery?

    What is the battery's rated voltage, exactly? Is it actually 12V? Some "12V" batteries are actually specified as 13.8V.

    Donkey's suggestion is good (although it's drawn upside down, with negative at the top, and you need to confirm that the charger output connector is wired with negative on the outer and positive on the inner contact). But inserting the diode between the trickle charger and the battery could affect the battery's charging - it depends on exactly how the charger works.

    Do you have a part number for the charger?

    The more information and details you post, the more accurately we can answer your questions.
     
    Last edited: Oct 7, 2012
  6. donkey

    donkey

    1,286
    56
    Feb 26, 2011
    I thought it was upside down. still a newbie but I got the concept right i think lol
     
  7. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

    8,393
    1,266
    Nov 28, 2011
    Just load the image into an image editor, flip it and rotate it 180 degrees, and you got it right first time!
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-