Abstract
The rapid development of the smartphones penetrated in every aspect of daily life starting from the health care, education, economics, social life etc. The prominence of the smartphones comes due to their size and connectivity, size made them the first handy personal computer available for 24\7 to the users. Unfortunately, the power of these smart devices and applications are limited and dependent on their battery power, which directly effects their usability. To overcome the shortage of battery life, scientists conducted several researches to get more power efficient hardware components, operating system and applications. This paper introduces review to the different techniques introduced to reduce the power consumptions in smartphones by using any mean.