some mosfet drain leakages

Yup, a test I sometimes do on small power FETs is use the DVM to charge the gate to ~ +3 or -3 V, and then check the drain current with the same meter, assuming the gate will hold the charge long enough to perform the test. If the transistor is clean, it will hold the charge for a lot longer that that.

Jon

And the data sheets make it clear that neither has any kind of built- in protection diode, so you can build up enough electrostatic charge to break down the gate-substrate oxide (or whatever - nitride layers were rather tougher) layer by shuffling over a nylon carpet on a dry day.

-- Bill Sloman, Nijmegen

So don't do that.

Duh. Rich

I've had some fun with a 2N7000, a battery, an led and a resistor. Connect the obvious way, with the gate floating. You can do all sorts of cool stuff with the floating gate, including charging it by shuffling around the floor and approaching, or touching, the gate. I haven't blown one up so far.

John

In a 2N7000?

I figure that if I damaged a gate, the gate leakage would go up. Even after playing with them, the gate voltage will hang stable for hours.

John

Try checking the RF noise figure before and after...

Using the diode check function? Nice!

Well, I don't have the gear to measure RF noise figure. Is a 2N7000 any good as a low-noise RF amp? Capacitance is sort of high.

John

Not necessarily; the damage can be subtle; the RF noise figure is a sure way to tell; something i learned at Fairchild in the uA709 daze.