How long... LED on time without resistors?

[Archangel]

Well that was EASY!!

What if I want to use a 5 Volt supply for testing?

I thought about just ramping up the "on" time until the brightness matches the brightness of a properly current limited LED of the same type.

Hi Dwight,
I will give a metaphor to answer the question: how long can I hold a lit cigarette to my skin without a heat shield in between?
It is exactly the same scenario, you are abusing the components both PIC and LEDs, how long before complete burnout? I guess it depends upon the particular batch of parts. I "think" they do sell LEDs with internal resistors, or at least they did. FYI they also sell transistors with internal bias resistors too . . . call them digital transistors. I know it is NOT Uncommon for designers to overdrive components particularly when using PWM, but IMHO it is not the best practice. If this is a home project, and not life critical then who cares right? Then do it, if/when it fails you will fix it.


EDIT:
Here is a link to Mouser's search for 5 volt LEDs: http://www.mouser.com/Optoelectronic...rd=LED&FS=True

This link will allow you to select from whichever voltage and current values you like: http://www.mouser.com/Optoelectronic...rd=LED&FS=True