Wanna get your advice regarding powering up Arduino Uno using AC/DC Adapter to the barrel jack.

The first adapter I use couldn't work and the shop which I bought it from said the adapter was short circuit-ed.

Out of goodwill, she replace it for free and I tested it out again. The first few tries it worked perfectly fine but stopped working (suspected short-circuited again).

The adapter output is DV9V - 2A.

The circuit consists of 2 ultrasonic sensor and 1 buzzer.

I am quite sure the Arduino circuit does not draw more than 2A of current.

Any idea what's the issue? Thanks!

EDIT - enter image description here

I've uploaded a photo of the schematic done using Tinkercad. I am using a different breadboard thus the configuration as shown.

  • As you suspect a short circuit, have you checked for that? Also: Are you sure, that the power supply is broken? Or is it the Arduino? The barrel jack is connected to a voltage regulator, which will go into emergency shutdown, if you draw more current through it, than supported, (for genuine Arduinos). Cheap clones might get their voltage regulator destroyed. Please show your real circuit, so that we can check for a short circuit
    – chrisl
    Commented Jul 13, 2020 at 10:19
  • You need to troubleshoot the system. 2 failed power supplies in a row seems suspicious. I would try to rule out a problem with your Arduino or with your circuit. Buy a multi-tester and measure the voltage out of your power supply, and the resistance of your circuit. You might want to add a 2A fuse to your power supply to protect it. (You'd need a male and a female barrel jack connector, a fuse holder, some wire, and a soldering iron.)
    – Duncan C
    Commented Jul 13, 2020 at 11:41
  • Switch-mode based DC adapters virtually have to have short circuit protection and OCP to pass UL certification (otherwise it would fail). Most smps driver chips have that built-in as well, so if it's a recently made adapter, that's probably not the issue.
    – dandavis
    Commented Jul 13, 2020 at 19:21
  • Hi @chrisl I have uploaded a photo of the schematic. Can you help to take a look? The Arduino works perfectly fine because it is able to power up via USB. I am supplying a 2A into the Arduino which requires only 1A. I read on forum that supplying more current is fine
    – Zac
    Commented Jul 14, 2020 at 4:24
  • @DuncanC Hi, I've tested the adapter, it doesn't have any voltage output. So pretty sure the adapter is damaged. I'm trying to find out why the adapter is damaged
    – Zac
    Commented Jul 14, 2020 at 4:25


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