Jim Thompson wrote:
On Fri, 20 Oct 2006 08:10:41 GMT, Robert Baer
Jonathan Kirwan wrote:
[snip]
You can do a one-point calculation of Is, just as I did earlier. That
works and is simple, but it may not be enough at times. You can do
better than this by doing curve-tracing of Ic versus Vce with a range
of fixed Vbe's set up. Then take each fixed Vbe that you used and
find it on the Vce (horizontal) axis and mark them. Take a vertical
line up from there and mark its intercept with the associated Vbe
curve you traced out. Do that for each Vbe you used. That will give
you points where Vbc=0. (Not done like you did with B and C shorted.)
This allows for a more accurate estimation of Is, drawing the line
back to its intercept with the Ic axis.
Jon
Forget all of that. KISS.
I made a measurement and it did not even come close to what Mr Pease
said.
I made another measurement at a different current with the same result.
I am puzzled about that discrepancy.
Robert, Post your lash-up. You must be doing something terribly
wrong.
...Jim Thompson
Very crude; the base and collector leads were twisted together and
poked into the "sideways: hole in the banana connector which then was
cinched up; the emitter lead was treated in a similar manner to the
other banana connector of an HP5326B in DVM mode.
An adhustable HP6228B supply in series with a fairly large resistor
and current meter supplied the current to the lash-up at the banana
connector plugin holes.
When i have time, i will try with the collector open.