Gamry Instruments Interface 1000 Operator's Manual page 67

Appendix A: Interface 1000 Specifications--Floating Operation
11. The total error in a voltage measurement is:
Error = Zero Offset Error + Gain Error × Voltage
For a 1 V signal, the theoretical error can be as high as 3 mV. This error is typically less than 0.5 mV.
12. Offsets are summed into the signal. Offset inaccuracy is approximately ±0.05% of the setting plus
±0.5 mV.
13. There are nine hardware current ranges, separated in sensitivity by decades. The ranges are 10 nA,
100 nA, 1 µA, ... 100 mA, 1 A full-scale. The ×10 and ×100 gains add two virtual ranges of 1 nA and
100 pA full-scale.
14. The voltage across the current-measurement resistor, Rm, is as shown. On ranges below 1 mA, the
working-electrode voltage is similar to the voltage across Rm. At 1 A and 1 MHz, the working electrode
voltage can be as high as 0.4 V, because the cable has both resistive and inductive impedance.
15. The total error in a current measurement is:
Error = Input Current Offset + Range Zero Offset × FS Current + Gain Tolerance × Measured Current
For small currents (pA) the first term is usually dominant.
For large currents (uA), the first term can usually be ignored.
The units for the error are amperes.
16. Drift can be approximated by simple drift in the Range Zero Error. In reality all three terms in the
equation above can have drift.
17. The Current-to-Voltage converter bandwidth is a function of the current range, the cell cable, and the
IEStability setting. The bandwidth can be very low on very sensitive ranges. Longer cell cables add
capacitance and slow the current measurement.
18. The total error in a voltage setting is:
Error = DC Zero Offset + Gain × Voltage Setting
For a 1 V signal the theoretical error can be as high as 3 mV. In practice the error is generally less than
1 mV.
19. This specification is guaranteed by design. It is not tested.
20. This specification is measured by applying zero voltage across a 1 Ω resistor and measuring current
noise on the 600 µA scale. One µV of voltage noise creates a current of 1 µA. The filters in the ADC
Chain for the I Signal are used to limit the bandwidths as shown in the specification.
Signal-averaging via Gamry DSP mode further reduces the measured noise.
21. See Appendix D.
22. Isolation quality has both DC factors and AC factors (predominately at the 600 kHz power-supply
frequency). Only the DC leakage current is shown here. Consult Gamry technical support for
additional information.
23. Excluding external power adapter and any cables supplied with unit.
24. Excluding removable line cord.
Appendix A - 5