but it won't help with the current distribution problem. The PSU who's output after the diode drop is the highest voltage will end up sourcing all the current. Not what you really want. -tony Not quite, the forward volt drop of the diodes will even out the current between the individual units. Even shottky barrier diodes have a vf of >0.4v at the curents that would be involved. Lee. ---------------------------------------------------------------------------- ---- This email is intended only for the above named addressee(s). The information contained in this email may contain information which is confidential. The views expressed in this email are personal to the sender and do not in any way reflect the views of the company. If you have received this email and you are not a named addressee please delete it from your system and contact Merlin Communications International IT Department on +44 20 7344 5888. ________________________________________________________________________ This e-mail has been scanned for all viruses by Star Internet. The service is powered by MessageLabs. For more information on a proactive anti-virus service working around the clock, around the globe, visit: http://www.star.net.uk ________________________________________________________________________