RE the list on using a MOSFET for reverse polarity protection...... Should work fine for single power source--I used the circuit and it works really great--low low voltage drop with the right part. QUESTION: has anyone manage a clever way to do this with MULTIPLE power sources?? The FET itself will pass current in either direction when it is on. I need to run redundant, but isolated power sources into a data logger--a couple of internal batteries, external batteries, and a wall-cube power supply in a "highest voltage rules" configuration without any power being forced into the lower voltage sources. QUESTION 2: How about leakage when off? Anyone have any real-world measurements? Kelly ******************************************************************************** **** All legitimate attachments to this email will be clearly identified in the text. William K. Borsum, P.E. OEM Dataloggers and Instrumentation Systems < & <