How to use external power supply for Arduino

When should use the extra power supply

Power from 5v pin of Arduino may NOT be enough in some cases. For example:

• The sensors/devices consumes much energy
• A large number of sensors/devices are connected to Arduino

How to connect to the external power supply

In these cases, we MUST use the external powers for sensors/devices. To use multiple power source, it need to follow the following conditions:

• MUST NOT connect 5V of the external power supply to 5V of Arduino
• MUST connect GND of the external power supply to GND of Arduino

Example

• The external power supply for servo motor

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• The external power supply for relay

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• The external power supply for LED strip

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See Also

• How to know I2C address of sensor/device
• How to control speed of servo motor
• How to connect multiple I2C sensors/devices with Arduino
• How to convert string variable to integer in Arduino
• Switch Case statement does not work correctly