At 01:33 PM 10/26/2012, tim@nevyn.co.za wrote: >I have a small project that requires that I switch current on an off via a > PIC. What I need advice on is which transistor I should use to switch >power on and off to a device which is powered by a 3.7V 1200mAh battery. >To add context the PIC will need to remove and apply power to a cell phone >and hence the transistor needs to sit between the phone and battery. Is the PIC powered by the same battery as the cell phone? If so,=20 consider using a P-channel MOSFET with the source connected to=20 battery +, gate to the PIC via a 100R resistor, drain to the cell phone. I would use one of the modern extremely-low RDSon mosfets. The=20 keyword to look for is "trench", as in "TrenchFET" and=20 "PowerTrench". This is a series of low-voltage, very-low-RDSon=20 MOSFETs. You should have no problem finding a suitable part from=20 Digikey or other supplier. A couple of example parts are DMP2035U and FDS4465. dwayne --=20 Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .