For protection techniques see:-http://www.thebox.myzen.co.uk/Tutorial/Protection.html
A regular signal diode, such as a 1N914, would allow the voltage to go too, high, wouldn't it?
Yes you would think so but that is the system used in industry and we test it with an electro static zapping gun to test for compliance to the human body static model. It works, time and time again in the most demanding situations. https://en.wikipedia.org/wiki/Human-body_model