For reference I'm using the following datasheet: http://www.fairchildsemi.com/ds/TI/TIP120.pdf
I am going to use the TIP120 transistor as a switch to turn off and on a group of LEDs; however I'm getting confused on the research I'm doing and the datasheet. When looking at the table on page 2 ,it states the hFE is a min of 1000. However in Figure 2 (page 3) there is a graph of Base-Emitter Saturation Voltage and Collector-Emitter Saturation Voltage where it states Ic = 250*Ib (upper right corner of graph); this leads me to believe that the hFE is 250. Which value do I use to calculate Ib, 1000 or 250 (Ib = Ic/hFE)?
Secondly, on Figure 2 (page 3) can I use that graph to determine the Vbe at a particular Ic? The reason for asking is because I want to determine the resistance at the base I need (Rb = (Vin - Vbe)/Ib) and during my research it said that most Vbe is around 0.7V. Looking at that graph the Vbe can be anywhere between 1.25V to 2.5V for the TIP120, so should I use that value to determine the Rb?
Any help is appreciated.