At 05:18 PM 3/13/2004, Matt Marsh wrote: >Actually, I was just wondering, could I just use another tranistor >when selecting the porta pin so that power would then be taken from >the main positive power rail? (I might be way off here...) Yep - use an NPN transistor such as the 2n4401. Pinout is: leads down, flat towards you (so you can read the number) - left to right is EBC. Connect C to + supply, connect B to PIC pin, connect E to display. The neat thing about this is that you can connect C to the un-regulated supply if you wish - that way, the display current does not come from the +5V rail. In effect, you move the heat dissipation from the 5V regulator to the driver transistors. If this seems complicated - ignore it and just connect the C lead to the +5V rail. This is a common way to drive LED displays - the PIC pins can handle the segment current and the transistors handle the digit current. dwayne -- Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax Celebrating 20 years of Engineering Innovation (1984 - 2004) .-. .-. .-. .-. .-. .-. .-. .-. .-. .- `-' `-' `-' `-' `-' `-' `-' `-' `-' Do NOT send unsolicited commercial email to this email address. This message neither grants consent to receive unsolicited commercial email nor is intended to solicit commercial email. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics