On Mar 2, 6:21 pm, MassiveProng
wrote:
On Thu, 1 Mar 2007 06:43:01 -0600, "Anthony Fremont"
Gave us:

Since 3% accuracy is considered good in the scope world,

Huh?

Yep, didn't you know that scope you are using is only a few % accurate
on the vertical scale?

I think it would do
fine.

Bwuahahahahahahaha! Hilarious!

Hardly, it would be perfectly adequate for the job actually.

Dave

On 1 Mar 2007 23:53:14 -0800, "David L. Jones"
Gave us:

Yep, didn't you know that scope you are using is only a few % accurate
on the vertical scale?


You guys must be behind the times.

On Mar 2, 7:31 pm, MassiveProng
wrote:
On 1 Mar 2007 23:53:14 -0800, "David L. Jones"
Gave us:

Yep, didn't you know that scope you are using is only a few % accurate
on the vertical scale?

You guys must be behind the times.

My 6000 series Agilent is not behind the times, and it's only +/-2%
accurate on the vertical scale.
A good analog scope like say the Tek2465 is only 2% as well.

Perhaps those two are the exception huh? Care to post some links to
prove otherwise?
I could post until the cows come home scopes that are no better than a
few % accurate on the vertical scale.

Dave

"David L. Jones" wrote in
ups.com:

On Mar 2, 7:31 pm, MassiveProng
wrote:
On 1 Mar 2007 23:53:14 -0800, "David L. Jones"
Gave us:

Yep, didn't you know that scope you are using is only a few % accurate
on the vertical scale?

You guys must be behind the times.

My 6000 series Agilent is not behind the times, and it's only +/-2%
accurate on the vertical scale.
A good analog scope like say the Tek2465 is only 2% as well.

Better look again;IIRC,it's 1.25% . That does not include the cursors.

It's not really significant,as you can't get that resolution on the screen.


--
Jim Yanik
jyanik
at
kua.net

On 1 Mar 2007 23:53:14 -0800, "David L. Jones"
Gave us:


Hardly, it would be perfectly adequate for the job actually.


Wrong. That could easily leave the scope over 6% off.

It takes a much finer source to calibrate a device than the final
accuracy of the device being calibrated, dip****.

On Mar 2, 7:32 pm, MassiveProng
wrote:
On 1 Mar 2007 23:53:14 -0800, "David L. Jones"
Gave us:



Hardly, it would be perfectly adequate for the job actually.

Wrong. That could easily leave the scope over 6% off.

It takes a much finer source to calibrate a device than the final
accuracy of the device being calibrated, dip****.

Not in this case.
If he used a meter with 0.5% accuracy on DC volts then he could check
and adjust his scope's vertical scale to the same 0.5% accuracy.

And if you start crapping on about the tolerance of the resistor chain
adding up etc, then you haven't thought about this one hard enough...

Dave

On 2 Mar 2007 13:06:24 -0800, "David L. Jones"
Gave us:

On Mar 2, 7:32 pm, MassiveProng
wrote:
On 1 Mar 2007 23:53:14 -0800, "David L. Jones"
Gave us:



Hardly, it would be perfectly adequate for the job actually.

Wrong. That could easily leave the scope over 6% off.

It takes a much finer source to calibrate a device than the final
accuracy of the device being calibrated, dip****.

Not in this case.
If he used a meter with 0.5% accuracy on DC volts then he could check
and adjust his scope's vertical scale to the same 0.5% accuracy.

And if you start crapping on about the tolerance of the resistor chain
adding up etc, then you haven't thought about this one hard enough...


If you set a scope up with 0.5% accurate source validator, the scope
will NOT have that accuracy level. It will ONLY have that accuracy
level at that set point, and that is even questionable.

On Mar 3, 9:30 am, MassiveProng
wrote:
On 2 Mar 2007 13:06:24 -0800, "David L. Jones"
Gave us:



On Mar 2, 7:32 pm, MassiveProng
wrote:
On 1 Mar 2007 23:53:14 -0800, "David L. Jones"
Gave us:

Hardly, it would be perfectly adequate for the job actually.

Wrong. That could easily leave the scope over 6% off.

It takes a much finer source to calibrate a device than the final
accuracy of the device being calibrated, dip****.

Not in this case.
If he used a meter with 0.5% accuracy on DC volts then he could check
and adjust his scope's vertical scale to the same 0.5% accuracy.

And if you start crapping on about the tolerance of the resistor chain
adding up etc, then you haven't thought about this one hard enough...

If you set a scope up with 0.5% accurate source validator, the scope
will NOT have that accuracy level. It will ONLY have that accuracy
level at that set point, and that is even questionable.

Which is why you do it for each range and then spot check it to see
that there is no funny business. Perfectly valid technique for home
calibration of a scope vertical scale.

Dave

On 2 Mar 2007 15:09:30 -0800, "David L. Jones"
Gave us:

Which is why you do it for each range and then spot check it to see
that there is no funny business. Perfectly valid technique for home
calibration of a scope vertical scale.

Dave

It doesn't matter how many "places" you "spot check" it, you are not
going to get the accuracy of your comparison standard on the device
you intend to set with it. What you do is take the basic INaccuracy
of the device needing to be set, and add to it the basic INaccuracy of
the standard to which you are setting it. You CANNOT get any closer
than that. So, a 0.5% meter, and a 0.5% scope cannot be used together
to make the scope that accurate. You need a *finer* standard than the
accuracy level you wish to achieve.

You need to understand that as a basic fact, chucko.

MassiveProng wrote:
On 2 Mar 2007 15:09:30 -0800, "David L. Jones"
Gave us:

Which is why you do it for each range and then spot check it to see
that there is no funny business. Perfectly valid technique for home
calibration of a scope vertical scale.

Dave

It doesn't matter how many "places" you "spot check" it, you are not
going to get the accuracy of your comparison standard on the device
you intend to set with it. What you do is take the basic INaccuracy
of the device needing to be set, and add to it the basic INaccuracy of
the standard to which you are setting it. You CANNOT get any closer
than that. So, a 0.5% meter, and a 0.5% scope cannot be used together
to make the scope that accurate. You need a *finer* standard than the
accuracy level you wish to achieve.

You need to understand that as a basic fact, chucko.

The "basic fact" here is that we were talking about adjusting a 3% scope
with a .03% meter. Now that the number are back where they belong, please
procede to restate your case. The scope's vertical sensitivity could easily
be adjusted to within 3% using said meter, now can't it? Just like Keith
says......

On Mar 4, 12:38 pm, MassiveProng
wrote:
On 2 Mar 2007 15:09:30 -0800, "David L. Jones"
Gave us:

Which is why you do it for each range and then spot check it to see
that there is no funny business. Perfectly valid technique for home
calibration of a scope vertical scale.

Dave

It doesn't matter how many "places" you "spot check" it, you are not
going to get the accuracy of your comparison standard on the device
you intend to set with it. What you do is take the basic INaccuracy
of the device needing to be set, and add to it the basic INaccuracy of
the standard to which you are setting it. You CANNOT get any closer
than that. So, a 0.5% meter, and a 0.5% scope cannot be used together
to make the scope that accurate. You need a *finer* standard than the
accuracy level you wish to achieve.

You need to understand that as a basic fact, chucko.

LMAO!
If I use 0.5% accurate meter to adjust a something, then the accuracy
of that adjusted device at that point in time at that adjusted value
*becomes* 0.5%. The device that was adjusted only gets it's accuracy
figure of 0.5% *after* the adjustment. The 0.5% of the device does NOT
get added to the 0.5% of the meter in this particular case!

Dave

MassiveProng wrote:

On 2 Mar 2007 15:09:30 -0800, "David L. Jones"
Gave us:


Which is why you do it for each range and then spot check it to see
that there is no funny business. Perfectly valid technique for home
calibration of a scope vertical scale.

Dave


It doesn't matter how many "places" you "spot check" it, you are not
going to get the accuracy of your comparison standard on the device
you intend to set with it. What you do is take the basic INaccuracy
of the device needing to be set, and add to it the basic INaccuracy of
the standard to which you are setting it. You CANNOT get any closer
than that. So, a 0.5% meter, and a 0.5% scope cannot be used together
to make the scope that accurate. You need a *finer* standard than the
accuracy level you wish to achieve.

You need to understand that as a basic fact, chucko.
Furthermore, an analog scope cannot measure better than 1% (ie 0ne
part in 100 of what is on the scope face).
Now one can "cheat" by using a precision offset differenced with an
input and that difference amplified to *display* (part of) that
difference: note the "Z", the "W", and the more modern "7A13" type plugins.
But *on the screen*, i defy anyone to consistently "read" better than
one part in 100 (ie if 10 divisions on screen, read to better than 1
division on a consistent basis.
Thus, for a scope, one might use standards good to 5 or more places,
but the result will be no better than what has been called "slide rule
accuracy".
Do you believe all 15 digits of each and every number in a computer
printout?