In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Jon Williams wrote: No need to guess when Ohm's Law lets us calculate the value. The spec brief I pointed to earlier says the Vf of the LED is 2.5 at a current of 10 mA. The rest is easy: R = (Vdd - Vf) / If ... R = (5 - 2.5) / 0.01 ... R = 250 ---------- End of Message ---------- You can view the post on-line at: http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=87994#m88066 Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2005 (http://www.dotNetBB.com)