Is it true that when you leave electronics plugged on it consumes electricity even when off?

Answer 1

Keep in mind I'm not an electric engineer or electrician.

Leaving a phone charger plugged in without the cellphone plugged in is a waste of electricity. It's not a very big drain, but it's there and it costs you a tiny, tiny, bit more on your electric bills.

Without going into too much detail/complexity: the purpose of a phone charger or "adapter" is to adapt the electricity coming from your outlet into a kind that the cellphone can use. This process is not perfectly efficient and because of the way it works, it drains a small amount of power even if you are not charging your cellphone.

Now if you are interested in the more technical answer, I will do my best to do so:

To make the electricity coming from the outlet (Alternating Current) more suitable for the cellphone, the adapter must do at least two things. First it needs to step-down the high voltage coming from the outlet to a lower voltage that the cellphone can handle. This is done by using a transformer. The transformer is the main culprit, a transformer is basically a couple of wound-up coils of wire on an iron core. The outlet is connected to one of the coils, and this uses up a little bit of power even when you are not charging your cellphone since there is no switch on an adapter to disconnect the transformer coil from the plug.

Also, an adapter needs to convert the AC (Alternating Current) to DC (Direct Current). This is done by using diodes to rectify the AC to DC. This process can also cause some more of the power drain, costing you a tiny, tiny bit more on your electric bill.

My technical answer lacks a better, and more detailed, explanation of AC, DC, Transformers, diodes, and etc. You should look up these on Wikipedia or do a Google search if you would like to learn more.

Below is a related link to a Wikipedia article that explains battery chargers, which are basically the same as cellphone chargers.

Answer 2

Yes. It does but very minimal. Look at the following link where someone plugged in 5 chargers to get a reading of 1W on the reading meter. Compare this to a 100W bulb being left idle when not in use. Stop using bulbs and start using CFL's that would help much more. Check out the link for the experiment: http://www.inference.phy.cam.ac.uk/sustainable/charger/

Answer 3

It depends on where the power switch sits electrically in the device.

If the device has a "soft power button" or sits in standby it does consume power.

If it's a direct interruption of the AC current feeding the device, it doesn't.

If you're interrupting the power AFTER the power transformer in the device, the transformer's primary windings still have power from the mains flowing through them, so the device still will consume power.