hello experts,
my stepper motor knowledge is limited i read in the forum but not able to understand properly !!!

- what is UNipolar and bi-polar difference , which is better in quality and durability now a days ??

- what is single phase and double phase stepper motor , also i see stepper driver specs. also mention this , i don't under stand this term.

- some stepper motor with encoder for better position contorl , is this really good for quality CNC build than regular stepper driver ??

can anybody help me to understand this term.

help appriciated...thanks in advance