> >as well, eg 4050

> think of just using a logic buffer...makes a lot of sense I think.

If you do decide to go that way, the 4049/4050 like most common
gate ICs can sink more current than they can source. With only one
LED probably doesn't make much difference either way. Putting
3 LEDs in series on 5V without R could be marginal depending
on their Vf

Connect the LEDs  V+ -- R --- >|--  pin. If you use the 4049 you
can keep the PIC s/w logic positive. ie BSF --> PIC o/p goes
high, 4049 (an inverter) o/p goes low and the LED comes on.
Obviously if you use a 4050 then BCF for LED on unless you
put the LED from 4050 o/p to 0V

In displays such as scrolling signs where strobing / PWM is on
permanently and there's no chance of static DC across the LED
the current limiting resistor can be reduced, depending on the
MS ratio of the drive. For example perhaps 47R or 56R with a
12V supply and a few percent duty cycle. And also IR LEDs that
may pass 10's of amps in microsecond bursts with only 1R to
limit the current. LEDs in such situations do get warm and you'd
need to read up on the tolerances to get the best out of them. For
an experimental circuit it would be wise to keep a couple of 100
ohms in series

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