Is it simple math such as for 100mA load Base has to be at 11mA, then for 40mA how much?
where as 2N2222 has max Power Dissipation of 625mW in which case I need higher capacity transistor right?
and eliminated out-of-spec ones
Yes TIP120 is overkill at 60V and 5A but it will definitely work!
would it b okay to build about 150 LED sign-board on a styrofoam/Cardboard