What Are the Common Screwdrivers?

Screwdriver, a tool used to twist a screw to force it into place, usually with a thin wedge shaped head that can be inserted into a slot or recess in a screw head. There are a word (minus) and cross (positive). There are also common hexagonal screwdriver. So, what are the common screwdriver?
1.Ordinary screwdriver, screwdriver is made with the head handle, easy to prepare, easy to use, but because there are many different screw length and thickness, and sometimes need to prepare a lot of different support screwdriver.
2.electric screwdriver, install and remove screws with an electric motor instead of manual, usually a combination screwdriver.
3.combination type screwdriver, A screwdriver to separate the head and handle, to install different types of screws, just replace the screwdriver head, do not need to bring a lot of screwdriver.
4.watch screwdriver, belongs to precision screwdriver, commonly used in the repair hand-banded watches, so this one said.