Yeah F5ing I used to be able to work out the voltage drops, current losses, through something as simple as passage of the electrical current through components such as even the very basic ones like resistors, caps, transistors, vacuum tubes and even the cables themselves.
Well I guess you already know all that some of that energy is converted into heat which we all know today is so important to get rid of before it destroys the components using said current, and one source that very familiar to us all in notably the CPU
Anyway sorry mate but did I quote 23v it is actually 21.3v which still in my mind is too high at the DC socket of the adaptor as it definitely states it's output is 19v and I could accept say 1v difference - allowing for fluctuations in the AC voltage.
Having said that in reality the voltage regulators in those devices should well regulate to within say +/- 0.015 tolerance but closer to 2.5v - hum? I mean it isn't rockets science as have built many adaptors for various purposes and one just adjusts until one gets those tolerances - or doe one?? Perhaps not in China?