A:Answerthis particular charger model won't work with i-phone 6 or i-pad air 2. This charger only works with older model i-phones and i-pads that have the wide charger access.
A:AnswerMost USB powered or charged devices operate at +/- 5v DC. Discovery Channel has a neat analogy on electricity: http://science.howstuffworks.com/environmental/energy/question501.htm