how to test mosfet 2n7002 to be tested whether good or fail, on board..please advise?

Question

in antistatic environment we r working one circuit which is having one MOSFET transistor 2n7002 switching component..how to test

Answer 1

There are a couple of ways that I can think of right off hand. They depend on what the surrounding circuitry is like.

Remember, a static discharge is a fairly high voltage arc. So one possibility is to measure the resistance at the transistor and compare it to a known good board. The low voltage used to measure the resistance shouldn't hurt anything, but like I pointed out, this depends on the circuitry. One company I am familiar with used to do this to trouble shoot a circuit. They had a whole list of resistance readings for various points in a circuit. It was quite helpful.

You might also power the board and use a scope to measure wave forms. Or even a DMM to measure voltages.

Another way is to use a curve tracer. Again, depending on the circuitry.

Answer 2

Testing in situ (on board) is not advisable, since surrounding components can give you false readings, especially for a MOSFET which has a very high internal resistance.
some ideas:
http://www.uoguelph.ca/~antoon/gadgets/mostest.htm
http://www.4qd.co.uk/serv/mostest.html

Answer 3

2n7002