Don't forget FETs can be damaged by static. Use ground straps and static mats when installing them, and make sure the topology o fthe circuit will drain off voltages if the circuit is turned off. The symptom you will get if you static shock a FET is, it will work fine a time or two then quit. Same with PICs. Are you, perhaps, wearing a wool sweater? -- Lawrence Lile Harold Hallikainen Sent by: pic microcontroller discussion list 11/14/2003 12:57 PM Please respond to pic microcontroller discussion list To: PICLIST@MITVMA.MIT.EDU cc: Subject: Re: FET getting damaged by unknown reasons One way I blew out some FETs was inductance in the source lead. I was driving the gate with a low impedance (a PIC, of course). When the drain started drawing current, it appears I got a transient pulse between the gate and source due to the source being "pulled up". I put a small resistor (10 to 100 ohms) between the gate and the driver and the problem went away. Gate capacity then kept the source/gate voltage from changing too far (over the gate/source voltage limit). Also, since this is driving a motor, I assume there's a diode across the motor for when the FET opens, right? Without it, I'd expect the drain voltage to go real high when the FET opens. Harold -- FCC Rules Online at http://www.hallikainen.com/FccRules/ -- 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 -- 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