> The phone normally operates from its battery, the amount of ripple present from a battery is zero. I'm not sure what source exactly you want me to provide to cite the fact that a phone has a battery, anyone knows that.
I was asking for a cite on the claim that the phone has a better voltage regulation circuit. AFAIK both the RPi and phones are using jellybean switching regulator ICs to convert and regulate the voltage. Even an expensive switching regulator is going to have a hard time competing with the PI's linear regulators in terms of output noise. (The Pi, of course, can afford to waste a bit of power, whereas the phone needs to juice all of the battery capacity.)
>Also, typically a phone will use a buck converter (or perhaps buck-boost) to drop its voltage, rather than a switching regulator.
Erm, a buck converter is a kind of switching regulator (one that drops rather than increases the voltage). See for example the buck/boost/etc. options under 'Topology' in Mouser's switching regulator category, or the Wikipedia definition:
http://www.mouser.co.uk/search/refine.aspx?N=10368713
https://en.wikipedia.org/wiki/Buck_converter
>Some phones do have problems operating while plugged into crappy adapters (the power does pass through), the most common being that the touchscreens stop working.
This undermines your point that phones somehow have better voltage regulation circuitry than the RPi. Many that will run directly off USB power have exactly the same issues.
>Good on them for finally doing it, but it should be included with the device, and should have been included from day 1.
But why are you still advising people not to buy the Pi because of power supply issues? I bought my first Pi a few months ago and made sure to get an adequate power supply (not difficult). I haven't had any problems.