Why Is My Board Getting Hot?

Short answer: too much current or a wiring mistake is forcing the board to dissipate more heat than it can handle.

Common causes

  • Short circuit: 5V or 3.3V connected to ground.
  • Overcurrent load: powering motors, servos, or LEDs from the board.
  • Wrong input voltage: too high on VIN or barrel jack.
  • Bad regulator: linear regulator overheating under load.

Quick safety steps

  1. Unplug power immediately.
  2. Check for hot components with care.
  3. Inspect for shorts or miswired rails.
  4. Power the board alone before reconnecting peripherals.

Warning

If a chip is too hot to touch, power off and fix the wiring before you try again.

The VIN and regulator trap

Feeding 9V or 12V into VIN with a heavy load forces the onboard regulator to burn off extra voltage as heat. That heat can reset or damage the board.

Use a buck converter to supply a clean 5V instead.

LEDs and power rails

Large LED strips or many LEDs can overload the 5V pin. Power them from a separate supply and share ground.

Bottom line

Boards get hot from shorts, overcurrent, or too much input voltage. Fix wiring, use a buck converter, and power heavy loads separately.

Related: How do I use external power safely? · Can I power a motor or servo from the Arduino 5V pin? · Why does my Arduino reset when the motor turns on?