Output Current

What is the output current on the 5V pin on the Arduino Uno? When I connect 3 IR sensors and one Ultrasonic sensor (to the 5V pin) and make a Line Follower & Obstacle Avoider and power the Arduino board using the USB it works perfectly but when Arduino Uno board is given power using 6f22 9V Hi-Watt battery the robot moves randomly and sometimes stops. Is current the problem? If no, then what might be?

6f22 9V Hi-Watt

"Hi-Watt" ? :smiley:

Put it back in the smoke-detector, where it belongs.

Nominal Capacity: 520mAh

And don’t post the same question in different parts of the forum.

This is called cross-posting and IT WASTES TIME.

Duplicate post deleted.

Perversely, it depends on the voltage of the input. A higher input voltage means the voltage regulator must do more "work" to reduce the voltage to 5V. The little voltage regulator on the Uno board can't power common components like LCDs with backlight when it's running on 12V, but it can do so at 7V.

You need to work out the power dissipated in the voltage regulator and then look at the temperature rise, based on the datasheet figures.

That kind of 9v battery is terrible. It is unsuited for any arduino-related purpose - they can only provide very limited current.

You say you have line follower + obstacle avoider - that implies that your device has some means of locomotion (motors, presumably), else you couldn't follow a line (though avoiding obstacles is a cinch). Those little rectangular 9v batteries cannot provide sufficient current to power all but the tiniest of motors - they are just not up to task for most electronics tasks.