The displays are common anode, and crave 8-10 V at a max of 25 mA. Using the 74LS192 to sink 16 mA *should* give a bright enough display. After a quick test setup, 9.4 V at 15.2 mA is a little on the dim side, but it would suffice. I'm going to at least 20 mA though, which is very easily...
My plan was to use a voltage regulator so that I would have a 9 or 12 volt supply and 5 volts regulated off of that, so two power supplies isn't a problem.
The OC buffer is sounding like a better idea now that I've tried breadboarding it with no success. The breadboard setup is pretty clunky...
My concern about using a bipolar transistor is that the logic won't push enough current. Granted the signaling current is on the order of microamps, and I have some 2N3904s lying around, I'll see what I can do.
thanks all
I have some 7-segment LED displays which require ~9 volts to run. I want to control them using a TTL digital logic circuit which works perfectly on it's own when 5-volt displays are used. I need a way to power the 9 V displays from 5 V logic via a BCD-to-7seg decoder chip. I anticipate having to...
