Zener diode is forward when used with the general use of diode forward basically the same, after the forward pass is essentially the same voltage across all about 0.7V. In theory, the Zener diode voltage regulator can also be used to make a positive regulator works, but its value will be lower than the regulator 1V, and regulator performance is not good, generally do not use a separate regulator for forward conduction features to the regulator, but with the reverse breakdown voltage characteristics. Value is the reverse breakdown voltage regulation.