How is measurement accuracy calculated when the 42841A is used with the 4284A, 4285A or E4980A?
The measurement accuracy is the sum of the measurement instrument accuracy and additional error produced when the instrument is used with the 42841A and bias current test fixture.
When the E4980A or 4284A is used with the 42841A (and 42842A/B), the instrument accuracy for DC current bias measurement is specified separately from that for no bias or voltage bias measurement because selectable measurement ranges are limited to low impedance ranges. When the 4285A is used with the 42841A (and 42842C), the 42842C additional error is added to normal 4285A accuracy (same as 4285A accuracy for no bias or voltage bias measurement).
For the details of accuracy calculation, please refer to the specification described in Chapter 4 of the 42841A operation manual.