If i leave my charger plugged in and the switch is on without any device charging, does it ‘waste’ electricity? Why/why not?
In: 58
The power in your wall is AC. Your device charges with DC. Essentially, there is a rectifier circuit that converts the AC to DC. But now the voltage is much too high. You need 5v and you are at 120v, so they use a device called a buck converter to drop it down. The buck converter uses an inductor to smooth out the choppiness and a high speed switch to pulse the DC through the inductor to end up with a smoothish lower average voltage for the DC.
Yes, the transistors that perform the switching in the buck converter have a quiescent current at all times. Additionally, there is some magnetizing current lost to the inductor and some voltage drop in the rectifier circuit. There is a small amount of power being lost to this at all times it is plugged in.
Any time electricity flows through something a bit is dissipated as heat. (Except in something called a superconductor!) The more resistance it experiences along its path, the more energy is lost to heat. The longer, skinnier, or tougher the path the more resistance it experiences.
This is the basis of electric heater function or a coffee maker. They just provide a hard to travel path for the electric.
The wires in your wall are always live, so, when you plug in your charger you are adding more path and a tougher path to travel so more heat is lost.
Inside the charger is a really long spool of wire and some semiconductors and capacitors. They all stay on, traveled by electric, ready for you to plug your phone in.
A simple way to save money if you want to keep your charger plugged in all the time is to use switch before it like a power strip.
It used to be that some chargers wasted power that wasn’t going into charging a device, and it used to be with televisions that parts of the circuits that took time to “warm up” (including the cathode-ray tube) were kept on so that TVs would turn “instant on.”
With more modern switch-mode chargers, and LCD/LED TVs, this wasted power has been reduced dramatically. Government regulation has required these more efficient designs to be used, and the market has shifted from CRT-based TVs to flat-panel displays, so the amount of power “wasted” by plugged-in, but turned-off devices is now just a small percentage of the power in regular use.
Yet, we have billions of people on the planet, and multiplying the small power usage of individual devices by the number of people can be an impressively large number. However, compared to the many other kinds of losses in power distribution systems (resistance in power wires, fringing magnetic fields in high voltage lines, transformer conversion losses, etc.), it’s still a small percentage of the “wasted” or “lost” power.
Short answer, your charger converts AC power to DC power and even if nothing is plugged into it, that conversion will draw a little something. It’s not much, though.
Yes but by such a small amount that it doesn’t matter unless you have dozens of things plugged in and even then do you want to unplug 80 things before bed to save 50 cents?
A lot of comments here try to define the “waste” aspect of the question. For this purpose any energy used to not fulfill the devices primary function is wasted energy.
In chargers there are small buckets of magnetism. The magnetism is created by using electricity. But every bucket is not perfect – it has holes, so magnetism is leaking.
Additionally, there are other components used to keep filling the buckets that aren’t perfect either.
Buckets = coils.
For a more nuanced answer; the electricity is actually isn’t “wasted” if the temperature outside is couldn’t than inside. The energy becomes heat in a 1:1 ratio.
Now if it is hotter outside than inside and A/C is cooling the house, the charger and the A/C are in a fight. For every unit of heat the charger wastes the more the A/C has to counteract.
So in the winter time I see no problem, but at summer it can add up. Especially if you have a lot of devices in stand-by.
Yes, but the waste is pretty minimal. Chargers need to convert the 120V AC voltage of the wall into a 5V DC power your phone actually uses. This conversion requires transformers which consists of a wire going from the hot prong, wrapping/coiling around a magnetic core, then going back out to the neutral prong. There’s a similar setup on the device side with fewer windings on the same core. I’m going to avoid the technicalities of how a transformer steps down the voltage to keep things simple, but I can go into more detail if people are interested.
Since there’s a complete connection between the hot and neutral prongs, electricity can flow through the device. Now there’s no real resistance with this setup without something plugged in on the other side, so it draws very little power until something is plugged in. We’re talking less than a dollar per year.
No. It’s pennies. Not worth the hassle. You waste more energy when you open the fridge door.
Buy a kill-a-watt and see for yourself.
I feel like none of these are answering the question so I’m going to take a try.
If you imagine a charger as a person being awake and when it’s charging something he/she is talking to someone else, you could imagine it takes a lot of energy to talk to that other person. But how do you know if the other person is there? You need to stay awake, you need to let others know that you’re available, etc. There’s a lot going on to be idle. But even when you’re alone, there’s a voice in your head having a small conversation, transferring power (in our analogy). It transfers a lot less than when you’re talking with someone else but it’s still there and it’s always there. An adaptor works in kind of a similar way, no matter how perfectly we design it, there’s always going to be something to sense if something else is plugged in, and or there’s going to be leakage in imperfect parts.
By leaving your charger plugged in, you reduce its lifetime. As every electric appliance, it will not last forever, and the cost of the charger is much more than the idle electricity it uses.
PS: I will not repeat what other said about electricity.
Latest Answers