In sci.electronics.design Paul Burridge wrote:
On Tue, 21 Sep 2004 20:56:00 +0200, "Helmut Sennewald"
wrote:

Hello Paul,
Vgs_off seems to be often specified at Id=1nA. The measurement
at such low current levels takes a lot of time and it requires a
very clean test fixture.

How have you measured at exactly Id = 1nA +/-0.1nA ?

Hi Helmut,

Is it 1nA? I thought it was 5. No matter.
Yes, I'd expected someone to point out that the "negligible current"
point was the likely problem area. I can't honestly say that I have,
because my DVM drops out at 0.01mA! However, in the context of the

Turn it to voltage.
Most meters (the four I've measured) have a 1Mohm or so input impedance
on the 200mv range.
This is 200nA full scale.
Probably best to do the test twice, with the meter leads reversed though.