Arduino with 9V: gets hot?

Discussion in 'Embedded Systems and Microcontrollers' started by Captain E, Jun 24, 2015.

  1. Captain E

    Thread Starter Member

    Jun 16, 2015
    81
    6
    Hi!
    Using the Arduino UNO, I want to power it from a battery, so I watched a tutorial and plugged in the 9V battery to the VIN pin and to ground.
    The Arduino has a recommended input voltage of 7-12 V, as the documentation says. When I did this, the Arduino got much more hot than it is with 5V from a USB cable. It's not melting, and I can keep my finger on it without the need to remove my finger, but it's still hot.
    1. What temperature is dangerous for the Arduino? (Maybe I'm overreacting on the heat)
    2. How can I use a 9V powersource and get 5V to my components?
    3. SHOULD I even use a 9V power supply?
    Thanks!
     
  2. nerdegutta

    Moderator

    Dec 15, 2009
    2,515
    785
    Are you using the 3.5mm power connector?
     
  3. Captain E

    Thread Starter Member

    Jun 16, 2015
    81
    6
    no :0
    I read you can just plug in a 9V in the Vin pin? :00
     
  4. DickCappels

    Moderator

    Aug 21, 2008
    2,653
    632
    Is it the voltage regulator that is getting hot, or is something else getting, and if something else, what is getting hot?

    Note: Check to see whether you power supply is connected in the correct polarity.
     
  5. takao21203

    Distinguished Member

    Apr 28, 2012
    3,577
    463
    no you cant.
    the only reason its maybe surviving is the battery voltage breaking down.
     
  6. Captain E

    Thread Starter Member

    Jun 16, 2015
    81
    6
    What do you mean, should my Arduino be broken now?? <:0
     
  7. Captain E

    Thread Starter Member

    Jun 16, 2015
    81
    6
    Most of the heat is at the power connector, on the two cylinders.
     
  8. DickCappels

    Moderator

    Aug 21, 2008
    2,653
    632
    If you are lucky, the maker of the board put in a rectifier to protect the circuit from the power supply being reversed and the power supply is driving the rectifier. Make sure your power supply voltage is the correct polarity.
     
  9. takao21203

    Distinguished Member

    Apr 28, 2012
    3,577
    463
    well applying 9v to the jack is OK and a little heat is OK too.

    Good question if it is broken. You should be able to find out yourself??

    For the dummies: Download the Arduino IDE, load the blink LED sketch + flash it.
     
  10. Captain E

    Thread Starter Member

    Jun 16, 2015
    81
    6
    Yes it seems to have survived, everything works :p phuu....

    Thanks for the help! :)
     
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