# Maximum and minimum power(watt) for arduino uno

Hi, Can someone give me Maximum and minimum power(watt) for arduino uno.

Thanks

You question is a bit wrong.
Power where input or through the output pins?
We don’t talk about power output only current output, it is 40mA per pin with a total of 200mA over all pins with some restrictions on pin combinations, see section 28 of the data sheet.
Minimum power out doesn’t make any sense at all unless you say it is zero.

The arduino itself takes about 30mA plus any current supplied to the pins.
The power depends on your input voltage, it can be 5V regulated or between 7v and 24V unregulated.

"Power" is a concept that causes people a lot of confusion.

Most understand Mr Ohm's law....

If everything else stays the same, and you use a bigger battery, or other source of voltage, you WILL get more current.

If there's no change in the source of the voltage, and something reduces the resistance of the circuit, you WILL get more current.

If you multiply the voltage number and the current number, you get the "power".

Power and current are RESULTS. Voltage and resistance determine what current, and thus what power, will be involved in any given situation.

=== A little "gotcha"....

A 9 volt battery doesn't always supply 9v (same story also applies with other voltages, other sources of voltage)

It only supplies 9v for "a while"... you knew that... and it only supplies 9v as long as you keep the current flowing from it below a certain "reasonable" level. You may not have understood that?

While we're at it: How long will the battery last? How long is "a while"? A typical 9v alkaline (non-rechargeable) battery will give you about 56 hours of operation if you put it in a circuit where the resistance means that the current which flows is 10mA. Or, you could have about 112 hours of operation at 5mA. Again, there are limits. I doubt you will get 1 hour of operation at 56 times 10mA. This property of the battery is called it's capacity.

(For more on capacity, see http://en.wikipedia.org/wiki/Nine-volt_battery)