Is power consumed from battery to run the phone when charging? I want to download torrents while keeping the device plugged to charge. My device is made by Samsung.

Is the power consumed from charger, or battery, to power the device when charging? Will my battery take a hit?
Of course your device requires power to run – whether you've set it for charging or not. Question is: Does it use more power than it gets by charging? Which depends on multiple factors:


Your "power source". USB only charges with 500 mA (USB2) resp. 900 mA (USB3), A/C with up to 2 A.
Your devices power consumption. Depending on what it's doing. Display turned on max brightness already uses more than USB can provide, recording/playing HD videos takes bit bites, and even a WiFi download might exceed that (see the table in my answer here for some example values).


So in your case, all depends on the power source. If it's USB, it might just "hold the charge", get a "trickle" or lose "a trickle" or more when downloading on WiFi – or probably constanly lose charge when on mobile data.1

Btw: Your device might get quite hot in either case :)

Edit: Reading your question again after the discussion in the comments, it looks like I've missed a major part of it. Asking whether the "battery will take a hit", you most likely wanted to know if "torrenting while charging" causes any harm to your battery. Hard to say absolutely, as it depends on device an battery; but a good indicator is "temperature". Batteries used today are mostly Lithium Ion (LiIo), seconded by Lithium Polymer (LiPo). Both have in common not to like "extreme temperatures". So if in the process the device gets hot, that's an indicator your battery might not like that for long.

For details, please also see our battery tag-wiki and charging tag-wiki. Both give general information on them.



1: Note that the values in the linked post are exemplary only; your device might differ, but relations will be comparable.