What not to do to avoid damaging your Arduino Board

Author: Aus Electronics Direct   Date Posted:9 April 2019 

What not to do to avoid damaging your Arduino Board

Before you begin plugging and connecting things into your new Arduino development, it may be good idea to know what can damage the board.

Drawing more than 40mA from an output pin.
An Arduino can only supply 40mA per output pin. That means that you are not able to drive a motor or a speaker directly from the Arduino
board. You also cannot connect an LED directly without a voltage dropping resistor. 

Shorting an output in to the +5v, +3.3v or the ground pins, will also damage your board. As an example, if an output pin is connected 5v 
and you connect it to the ground, it will draw an enormous amount of current and burns out your Arduino almost instantly.

The pins and solder tabs on the underside all go through the circuit board, so make sure you don't place the Arduino on a conductive (metal) 
surface as it will short out the pins and damage your board.

Drawing more than 200mA from all output pins together.
The ATmega chip on your Arduino can only supply 200mA in total, so driving more than 10 LEDs @ 20mA each, for example, will eventually 
damage your board.

Supplying more than 5v (3.3v) to an input pin.

Supplying more than the operating voltage of the Arduino on any pin is very dangerous. Some Arduinos that run at 3.3v have 5v tolerant 
pins, but that's about it. This also holds true for other devices, like sensors or wireless chips: always check the voltages: if you 
connect the output of a 5V Arduino to a 3.3V chip, you might damage it.

Supplying more than 5v to the 5v pin.
The 5v of the Arduino board goes directly to the ATmega chip, that is rated for an absolute maximum of 6v.

Supplying more than 12v to the Vin pin.
There's an onboard 5v voltage regulator on the board, that will overheat and die if you feed it with more than 12v.

Drawing more than 500mA from the 5v pin (when running off an external power supply.
The onboard 5v voltage regulator can only supply 500mA of current. The 5vUSB has a polyfuse to limit the current to 500mA.

Drawing more than 50mA from the 3.3v pin.
The onboard 3.3v voltage regulator can only supply 50mA of current. This means that you can not connect power hungry 3.3v devices like an 
ESP8266 or nRF24L01 directly to the Arduino: you need an external 3.3v voltage regulator.

Reversing the polarity of the power supply.
If you swap the 5v or Vin pin with the GND pin, you'll kill the board almost instantly.The barrel jack has a diode to protect against reverse polarity.

Connecting a load to the Vin pin while using USB power.
If you connect a load to the Vin pin while the 5v to the Arduino comes from the USB connection, current will flow backwards through the 
voltage regulator, damaging the Arduino Board

Static electricity
Although most chips have clamping diodes and has protection against ESDs (electrostatic discharges), it may be wise to us an anti-static wrist 
strap, or to remove the carpet under your desk.

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