Caluclating battery life of microcontroller device

[nzkunal]

Hi
Wanted to know if anyone had any ideas on how to calculate the battery life for a hand held device I am making. It takes 3 AA batteries and spends most of its time in standby mode drawing 300uA at 4.5V. Is the approximate battery life for this just the mAH rating of the battery divided by the stand by current or is there a more complex way.
Any ideas?

 

[bobcat1]

Measure the current consumed by the UC(of full opration) during 1 Sec

And add it to the total consmption of the UC e.g:

with in 1 Sec the UC fullly work for 100Msc and reast for 900 Msc

100Msc * 20mA + 900msc * 300 uA = Total cosumption of power in 1 sec

this will give you the basic for the reast of calculation

Bobi