I have an NTE2013 which I want to use with an Arduino. I may be driving the base pins directly off of the Arduino or perhaps off of a 74HC595. Should I use resistors between the outputs and the base inputs to the NTE2013 to limit current? If so, about what resistor value ranges would work best?
The NTE2013 has the base current-limiting resistors (2700Ω) built in. You can connect its inputs directly to the '595 outputs.