[Yahya (OP)]

beside energy consumption  , will a charger be working when it is plugged in electric source and it is not plugged in a laptop.
I am worried because my laptop charger is always plugged in a electric source, I think it might be working all the time or perhaps at least working partially .
thanks,

[Colin2B]

Most plug top chargers have a transformer and this will consume a small amount of power even when not under load, mainly due to heating losses in the transformer.
If you compare the temperature of an unplugged charger to the same when plugged in you will notice a slight temp difference.

[syhprum]

It will probably cost you no more than £1.00 per year

[evan_au]

Older chargers contained a heavy iron-cored transformer operating at mains frequency (50 or 60Hz).

An Iron-cored transformer loses a fair amount of power to magnetising current and eddy currents, even when it has no load.

Modern chargers use an electronic circuit called an invertor, which produces a frequency of 100kHz or more from the mains voltage. This can be carried by a small and light ferrite-cored transformer, which has very low losses.
The electronic circuit is designed to go into low power mode when there is no load. It feels slightly warm, but not as hot as when it is charging a device.

Some countries are introducing legislation for minimum efficiency of chargers. These regulations effectively ban iron-cored transformers for small chargers.


In some countries you can turn off the charger at a switch as you unplug your iDevice, which eliminates the idle current too.

[vhfpmr]

Older chargers contained a heavy iron-cored transformer operating at mains frequency (50 or 60Hz).

An Iron-cored transformer loses a fair amount of power to magnetising current and eddy currents, even when it has no load.

Modern chargers use an electronic circuit called an invertor, which produces a frequency of 100kHz or more from the mains voltage. This can be carried by a small and light ferrite-cored transformer, which has very low losses.
The electronic circuit is designed to go into low power mode when there is no load. It feels slightly warm, but not as hot as when it is charging a device.

Some countries are introducing legislation for minimum efficiency of chargers. These regulations effectively ban iron-cored transformers for small chargers.


In some countries you can turn off the charger at a switch as you unplug your iDevice, which eliminates the idle current too.

Iron cored transformers are not particularly inefficient at 50Hz, a good transformer should be 95-98% efficient. The reason for rectifying the mains and chopping it at 100kHz is that the transformer can be much smaller and lighter at high frequency because the amount of energy the core has to store is less, and the core material then has to be changed to ferrite in order to keep the losses low at the higher frequency.

The reason that older power supplies are less efficient is that they use linear regulators rather than switch mode. In a SMR the control element is either on or off and therefore dissipates little power as either the current or voltage are near zero, by comparison a linear series regulator carries the full output current simultaneously with having a voltage across it and therefore wastes a lot of power.

It would be possible to get quite good efficiency using an iron cored transformer followed by a switching regulator, but if you're going to chop the supply at 100kHz for the regulator anyway it makes sense to put the chopper in front of the transformer so that you can use a much smaller and lighter one.

[syhprum]

Up until the fifties away from electric railways with a good receiver it was possible to receive American domestic MW broadcasts but now one can only hear continuous hash from switched mode PSU,s