I found this online:If you leave your mobile phone charger plugged into the mains you will use the same amount of electricity whether or not your mobile is being charged. So when you've finished charging your phone unplug your charger!Is it true? Surely if the phone isn't connected, there is no circuit, so no power will be used.?
The charger has a transformer in it that uses some power any time it is plugged in. And you risk wearing out the transformer sooner due to power surges if you do not have it on a surge protector. It might consume less power but it is still consuming power by being plugged in.
As you say, there is no circuit hence no load on the transformer, hence it will not use as much power as when charging, however transformers are not 100% efficient (it will get warm) hence even if unconnected it will use some power.
It does consume energy. Feel it, it will feel warm or even hot. It doesn't use much, but it is still a good idea to not waste this. Unplug it, or buy a power strip and turn off the power strip when it isn't needed.
Firefoxy gave the surprising answer to this. If the wall socket is on then a transformer will nevertheless soak up electrical energy, dropping maximum of it as warmth. circulate on, wrap it up in a woollen jumper for 10 minutes (now no longer or it is going to become a hearth risk). After this time you will experience how a lot warmth has outfitted up in purely a jiffy. If the wall socket is switched off then there is not any electrical energy utilization. If there's a thunder hurricane interior of reach you may desire to journey a rapid surge in the electricty grant that blows the transformer, that's why electric powered products would desire to continually be unplugged (no longer purely switched off) for the time of a hurricane if there is not any anti-surge risk-free practices.
The modern chargers used by the mobile phones do not use transformers, but rather a fully electronic circuit that converts the AC power to a small DC voltage. But as there's no power switch in the charger to physically open the circuit (turn it off), even when it is on no-load status (no phone being charged) part of the internal circuits will still be on. To illustrate, here's an example: a typical mobile phone with a 900mAh battery will consume approx. 3.5Wh when charging and something a bit under 0.5Wh when in 'standby' mode.
