Gamry Instruments Interface 1010 Operator's Manual page 71

3) Unity-gain bandwidth and slew rate are correlated. Each has five settings, with the highest slew rate
occurring at the highest bandwidth, down to the lowest slew rate occurring at lowest bandwidth. Both
are measured with 20 kΩ between counter and reference, and 100 Ω between the reference and the
working and working sense leads.
4) Measured with an external function generator connected to the Ext Sig In BNC.
5) The A/D and signal-processing chain in the Interface 1010 allows measurement of voltage signals as
large as ±13.107 V. The voltage on the working sense lead can be as high as ±0.4 V when measuring
1 A using a 60 cm cell cable. This implies a maximum voltage input on the differential electrometer of
±13.6 V.
In practice, the operational amplifiers in the voltage-signal processing circuitry cannot guarantee
voltages beyond ±12.5 V.
6) This specification is tested using a 2 GΩ resistor switched into the input and measuring the voltage
difference with and without the input resistance.
7) The differential impedance is measured between the reference and working sense inputs. This is the
impedance you measure when you record the EIS spectrum of an infinite impedance (open-lead) cell.
There is also a common-mode resistance and capacitance associated with the differential electrometer
inputs. These values tell you how much the electrometer response is modified by a resistance in series
with the source.
8) The bandwidth is for a sine-wave source with a 50 Ω output impedance driving either input. The
bandwidth is well in excess of this specification, which is limited by the measurement equipment used
in routine testing of the Interface 1010.
9) CMRR is common-mode rejection ratio. It specifies the ability of the differential electrometer to reject
signals connected to both inputs. The CMRR is measured driving both inputs with a sine-wave source
with a 50 Ω output impedance and measuring the error as a function of frequency. Resistance in either
input causes a loss of CMRR.
10) Voltage measurement is performed with a nominal 3 V signal input to the ADC signal chain. The
actual full scale is 3.2768 V. A 4 attenuator divides down higher-voltage electrometer outputs, so they
fit into a 3 V input, thus making a 12 V nominal (13.1072 V) actual full-scale range.
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.
Interface 1010 Specifications
71