So this is probably a rather simple question but electrical circuits are not my forte. I have been curious about how devices, specifically a laptop, can seamlessly switch between AC wall power (plugged in) and battery power?
This has been on my mind after doing some research on Lithium ion batteries and their lifespan in laptops. Some folks say that when plugged in, the laptop is using power through the battery and simply constantly charging it between that 90% and 100% range as it goes. Now this seems rather detrimental for the lifespan of the battery, so I can't imagine that most laptops are actually doing this. In my mind the simplest solution is just running completely on the AC wall power and leaving the battery alone when it is fully charged. So the question lies in how does the laptop switch from using AC wall power to using the battery, without shutting down for that split second when you unplug the machine from the wall power adapter?
My expertise is in the software realm, so I am rather ignorant on how the actual electrical engineering works in these cases. My simple guess was that a capacitor(s) supplies the power during that short time when switching between power sources. So, could anyone please explain how this actually works? Feel free to be as technical as you'd like. I have an engineering mindset, so I find the low level details interesting.
Thanks! Also, if this is a duplicate question, feel free to close or remove it and link the answered thread. I did some searching and didn't come across a similar enough thread.