Well, FWIW, the answer appears to be that the headphone jack of the Note 5 does provide some power. I received a Safe heart iOximeter today. I plugged it into the headphone jack and it works. I understand from the website safeheartus.com that this device may not work with some android phones (not a problem with iPhones) because they do not all provide sufficient power through the headphone jack. On reflection, it would seem that the headphone jack would have to provide at least the minimal power required for headphones or speakers. Sorry my question was not very clear, as I assume the power provided is inconsequential compared to the power available through the mini USB