In a comment to a recent blog entry somebody left a link to an interesting S60 utility that records power consumption and other interesting technical information while Noka NSeries and other S60 based devices execute programs. Running in the background, one can perform actions and see the impact on power consumption. The picture on the left for example shows power consumption during different states during mobile web browsing.
The left side of the graph (click to enlarge) shows power consumption while a web page is loaded, i.e. while the device is in Cell-DCH / HSPA state. Power consumption is at almost 2 watts during this time. Once no more data is transferred, the mobile is set into Cell-FACH state by the network which requires much less power. However, the 0.8 watts is still significant. After about 30 seconds of inactivity the network releases the physical bearer and only maintains a logical connection. In this state, power requirements drop to about 0.2 watts which is mostly used for driving the display and the background light. When the device is locked and the background light is switched off, the graph almost drops to the bottom, i.e. to less than 0.1 watts.
An excellent tool to gain a better understanding of power requirements of different actions and processes!