User manual

8-4 Relative and Math 2400 Series SourceMeter

User’s Manual

Math operations

Built-in math functions

The SourceMeter has built-in math functions to calculate the following:

•Power

• Offset Compensated Ω

• Varistor Alpha

• Voltage Coefficient

• Percent Deviation

The Power and Percent Deviation math functions use a single voltage and/or cur-

rent measurement to perform the calculation. The Offset-Compensated Ω, Varis-

tor Alpha, and Voltage Coefficient math functions require 2-point measurements

to perform a calculation.

Power

This math function calculates power using the measured voltage and measured

current values as follows:

Power = V × I

where:

V = measured voltage

I = measured current

Note that power is displayed in watts with “W” in the units field of the display.

Offset-compensated ohms

The presence of thermal EMFs (V

EMF

) can adversely affect low-resistance mea-

surement accuracy. To overcome these unwanted OFFset voltages, use the Off-

set-Compensated Ω measurement method. In general, this method measures

resistance (V/I) at a specific I-Source level and then subtracts a resistance mea-

surement made with the I-Source set to a different level (typically zero).

NOTE Offset-compensated Ω is also available from the CONFIG OHMS menu

structure. Using Offset-Compensated Ω from this menu automatically

selects zero as one of the source values. For details, see

Section 4, “Off-

set-compensated ohms.”