> > Easy. From spec sheet, .7v at 3mA, from Ohm's Law .7/.003 = 233 Ohms. > > That is either a minimum guaranteed current at that voltage or the maximum > guaranteed voltage at that current (the exact reference wasn't supplied, > so I didn't chase down the particular spec sheet line). Nothing says that > the current at 700mV couldn't be considerably higher. With a red LED that amounts to 15 mA at best. Say the spec is very conservative and you get "considerably higher". You're still likely to be less than 25 mA. We're talking PICs here, OK? Not mil-spec, the only time you'd do this is if you wanted a bright LED and no resistor. Otherwise you'd have to use some active component to boost the current. Please let me pose a question. What would you do to get 15 mA into a red LED when the PIC output is positive and it's supplied with 5 volts or less? I don't see any way to do it with a resistor, you won't get enough current. Cheers, Bob -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body