Identify Data Analysis Requirements - Keithley 4200A-SCS Reference Manual

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Section 6: Clarius

Model 4200A-SCS Parameter Analyzer Reference Manual

Identify data analysis requirements

In many cases, you may already know a needed analysis formula, even before running a test. In fact,

for a test, you may create a real-time formula in advance so that you can monitor its output during a

test, either in the Analyze sheet or graph.

However, in other cases, you may decide to perform an analysis after a review of existing test data.

The Formulator functions to use and the data to be included in the Formulator calculations must be

evaluated to meet your requirements. The following topics illustrate one such evaluation.

Determining the type of calculation: an example

For example, after looking at the BJT saturation voltage plot below, you need to have a better look at

the point where the slope of the saturation plateau becomes constant.

Figure 382: Formulator example data

You might decide to apply the function REGFIT to the CollectorV values (and corresponding

CollectorI values) between 1 V and 3 V. The line generated by REGFIT, when co-plotted with the

existing curve, should depart from the plateau at the point of curvature.

The following topics apply the REGFIT function to the data in the above figure to illustrate use of the

Determining range data for a calculation: an example

Many Formulator functions do not require you to specify row numbers (indices) as arguments.

However, some Formulator functions, such as REGFIT, require you to specify the range of data to be

included in the calculation (typically as the row numbers (indices) for the first and last values to be

included (refer to

Using the Formulator functions

(on page 6-226)). This requirement allows you to

apply a calculation to only a specific part of the data.

To find the corresponding row numbers (indices) for that specific part of the data, check the Run

worksheet. For example, referring to the figure below, you might decide to apply REGFIT only to the

CollectorV values between 1 V and 3 V. Looking at the Analyze sheet for this data, you note that the

CollectorV values between 1 V and 3 V are located between rows (indices) 52 and 152. This is the

range information that you need to create the regression analysis equation using REGFIT.

4200A-901-01 Rev. C / February 2017