hi tanks for the info.
but i still have a couple of questions, first... all my steppers are low voltage 2.8 and 3.1v.... this is the real voltage??? because it makes me think this motors are very weak, but the look big enough to move a CNC homemaded.... but also 2A are high current motors no???
If you supply the motor with (using the round stepper as an example) 2.8V it will consume its peak of 2A. If you use a higher voltage you must find a way to limit the current. That would imply high wattage resistors, or, more commonly, chopping the current. In practical usage the motors will never be run at their rated voltage but rather ~12V to ~40V is common; using a higher voltage results in a higher speed.
maybe this can be stupid question, but with my tester, how do i know which it the power, and whichs are the coils???....
Do more reading on unipolar and bipolar motors and how the coils are laid out. When you understand those differences then you'll realize you can set your meter to measure resistance and then test the resistance between the various wires to figure out the layout.
FYI, a motor with 5, 6, or 8 wires can be used in a unipolar mode. A motor with 4, 6, or 8 wires can be used in a bipolar mode. If you're planning on building your own driver with discrete components you will find it simpler to build a unipolar driver.
One last comment: in your posts you seem to be burning through periods and question marks at a very high rate. Take more care so that you don't exceed your quota.