Not 1255, is TIP125. I know about the current, but you said that there just need to be enough the base voltage for the current to flow.
Let's take an example from this datasheet:
https://www.electro-tech-online.com/custompdfs/2006/10/TIP120-DPDF-1.pdf
from the figure 10, when the collector current is around 100mA, the Vbe is around 1V for tip125. If the supply to emitter is 12V, the base need to have 11V to turn it off, right?
Let's say for tip120, NPN darlington. With the supply of 12V also, To turn it on, lets say 100mA at collector, the base current is 1/125th of it which is very small, then how about the voltage that is enough for it? Is it around 1.25V?
Thanks for your explaination..