5V Box Mod Question

I was looking at madvapes site in the How to. My questions are:

Why is pos wire from switch connected to voltage in and neg wire from switch connected to the control pin on regulator?
What is the resistor for?

The reason for asking is after 2 attemps regulator test fine but afer assembly I have 7.4 volts in 7.0 volts out 7.0 on neg and 7.0 volts on control pin. I'm using 2 14500 3.7 ea

You have to look on myvapes.com Mark has not got how to switched over yet

 

Well the regulator in question is a 5v 3amp resistor. If you are using 2 stacked 3.7 batteries, you will get roughly 8.4volts fresh off the charger.Now it will go down some after a little bit, but the regulator should be good for regulating up to 9v down to 5volts.As for the wiring diagram it is sound. I have used the 3 pin TI regulator and my mods work great. The 4th pin is for the control pin to downsize the current sent to your switch. That being said the smaller amp switches can be used without burning them up as quickly. I hope this helped a little bit.