I'm working on my little graphic equalizer meter display project.
The graphic EQ IC has a "split rail" reference output and since the supply is 5 volts I'm getting around 2.5, 2.6. But I don't really need this for the rest of the circuit.
I'm thinking about using some VFD "bargraph" indicator tubes for the display. The ones I have in mind need a filament voltage of around 2 volts at about 30-40 mA each, times 7.
I'd like to just slap a transistor fed from that reference on the base to regulate the filaments... 5 volts in on collector, ~2 volts out, just under 1 watt dissipation.
Darlington NPN will have too much B-E drop to work here. Can anyone suggest a suitable jellybean tranny for this purpose?