Over a 0-10V signal why 4-20 mA signals is preferred

Question

Over a 0-10V signal why 4-20 mA signals is preferred?

Answer 1

Commonly in a transistor some quantity of voltage is needed for turning it on. This voltage is cut in voltage. Up to this voltage the holds a non-linearity in its attributes. Further than this cut in voltage the char. of transistor is linear. This non-linear area lies between 0-4ma, further than 4ma it linear. This is why 4-20 ma range is employed.