Wonder if when I leave it connected to the outlet but not connected to the laptop, it still consumes electricity.
Does laptop charger wastes electric current when not connected to the laptop
power supply
power supply
Wonder if when I leave it connected to the outlet but not connected to the laptop, it still consumes electricity.
Best Answer
The answer for this is: YES, it will consume power, but such a little power that you may consider it irrelevant in terms of overall power consumption.
As you can see in the picture below (a schematic of an AC notebook adapter), the "entrance" of the circuit (“L and N 90 - 265 VAC”, in the lower left corner) has an AC transformer:
This component is responsible for converting the entrance AC voltage into another one in AC (if there is a load on the "output" side of this component). As you can see in the picture below:
Wikipedia has a good explanation about the operation of a transformer:
I marked in bold the main part of explanation to explain what will happen if there is no load on the transformer (in this case, it means that there is no device "consuming" power from the transformer). If there is no load, the secondary part of the transformer will not "act" on the primary part of it. It means that you will only have the input loaded with the entrance impedance of the transformer, or, in this specific case, the AC power from your electric outlet to an inductor of 200 µH in the transformer. A theoretical "ideal" inductor will not dissipate any power, but a real inductor will also have a resistive component that dissipates a small amount of power, usually due to the magnetic material in the core of the transformer producing "core losses". This will explain why you have a consumption of the AC adapter even if there is no "load" or on this case, if the notebook is turned off.
PS: This situation applies not only for your notebook AC adapter but to all adapters that have a transformer on their entrance.
Hope being helpful with my explanations.