DC Bias Module

The DC Bias Module is an optional plug-in data acquisition module for PRAP and ZAP. Its use requires the Basic Data Acquisition Module. The Basic Data Acquisition Module is an optional plug-in data acquisition module for PRAP while it is part of the regular ZAP package.

The DC Bias Module allows resonance spectra to be collected into a PRAP compound document as a function of DC bias applied to the sample. DC bias can either be generated directly by the impedance analyser, or can be amplified by a DC power supply.

The DC Bias data acquisition module allows resonance spectra to be acquired as a function of DC bias in a 'sawtooth' waveform. The DC bias is first set to a starting DC bias, and the instrumentation is allowed to settle for the settling time in seconds. A resonance spectrum is then acquired and stored in a PRAP compound document. The DC bias is then incremented or decremented by the specified bias step size, and the settling and measurement sequence is repeated. When the next DC bias exceeds the minimum or maximum DC bias, the next DC bias in the sequence is 'aliased' around the limit so that no DC bias is greater or less than the maximum or minimum DC bias, respectively. The number of resonance spectra acquired is determined by step size, maximum and minimum DC bias voltages, the percentage of sawtooth waveform cycles from the starting DC bias to be performed, and the number of times the whole sequence is to be repeated.

As an example, a starting DC bias of 15V, a step size of 5V, a maximum DC bias of 30V, a minimum DC bias of 5V, an initially increasing scan in DC bias, and 100% of a cycle would produce resonance spectra at the following DC bias voltages;

Spectrum

DC Bias (V)

1

15

2

20

3

25

4

30

5

25

6

20

7

15

8

10

9

5

10

10

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