On Wed, 25 May 2011 18:12:11 +0100, "Ian Field" wrote:


"John Larkin" wrote in message
.. .
On Mon, 23 May 2011 16:35:57 -0700, Tim Wescott
wrote:

On 05/23/2011 03:52 PM, Jim Thompson wrote:
Is this the correct pin out for a 2N7000...

http://analog-innovations.com/SED/2N...ak_Pin_Out.pdf

My expectations, from bipolar's, would be, facing the flat, leads
down. left-to-right...

D-G-S

My expectations, from browsing many data sheets, is that the pinout of
any three-terminal device is pretty well standardized:

Pin 1: random
Pin 2: random
Pin 3: random

Even the pin numbers can be random. I've seen all possible
permutations of 1-2-3 on various SOT23 parts. We use the "Motorola"
convention, and force any parts that we use into it.


So, maybe the 2N7000 is a little randomer than you thought -- it's still
normal.

All you need is a ohmmeter to discover/verify the pinout.


What I use is a Steinel continuity checker, it has a 12V keyfob battery & 2
LEDs. Stick the + probe on the drain and the - on source, usually stray
charge will cause enough conduction to make the LED glow, breifly moving
the - probe to gate discharges it then back to source and no light means
good MOSFET, move the positive to the gate to charge it and it conducts
again.

With unknown leadouts its relatively simple to identify the gate as there's
no continuity to either other terminal either way round. Which way round the
body diode is tells you half of what else you need to know.

A decent meter identifies the body diode by voltage drop, not continuity.

Meter I'm using here is half the price I paid for decent test leads for it

So knowing which two pins hold the body diode unambiguously identify the
three pins for me.