How do pth8080 react?

[lyberty5]

I am trying to build a iphone charger from a dynamo lamp for my brother's birthday, so i'm trying to regulate the varyiating voltage to 5volts, i already have a pth8080 wired up that outputs 5V, but i'm wondering how it will react to voltages under and other its input voltages...
Will it work? If not what should i use to regulate this voltage?
Thanks

 

[brunoip]

lm7805
remember to rectify and estabize the voltage.