Bio-Logic SP-240 User Manual

Manual for VMP300-based instruments
57
6. Advanced features
6.1 Bandwidth
6.1.1 Bandwidth selection of a standard channel
Nine bandwidth possibilities are available for the instrument. These bandwidths represent the
stability factors (SF) for a good measurement; if the bandwidth value is not well adjusted, the
potentiostat will oscillate. Selection of the bandwidth well adapted to the cell is mainly done
considering the response time of the studied cell and its capacity.
Table 6 gives information to help the user select the bandwidth most adapted to the studied
cell in the required experimental conditions. Note that the values of capacity are given for a
cell purely capacitive. The time constant (TC) is calculated considering the capacity of the cell
and the resistance of the current range used for the measurement, i.e. TC = RC. Cells located
in the green part of the table can be studied with all the bandwidths (1 to 9). Note however that
the most suitable bandwidth is underlined in the table. For the cells located in the white part of
the table, fewer bandwidth choices are available, whereas for the cells located in the red part,
selection of the bandwidth has to be done by the trial and error method depending on the cell’s
particulars.
Table 6: Help for bandwidth selection for a standard board considering the capacity and
the time constant (TC) of the studied cell, but also the experimental conditions.
Considering these factors the most appropriate bandwidth (SF) is given.
1 µA/
1 MΩ
10 µA/
100 kΩ
100 µA/
10 kΩ
1 mA/
1 kΩ
10 mA/
100 Ω
100 mA/
10 Ω
1 A/
1 Ω
TC
SF
TC
SF
TC
SF
TC
SF
TC
SF
TC
SF
TC
SF
10 pF
10 µs
6/7
1 µs
7/8
100 ns
1-9
10 ns
1-9
1 ns
1-9
100 ps
1-9
10 ps
1-9
100 pF
100 µs
5
10 µs
6/7
1 µs
7/8
100 ns
1-9
10 ns
1-9
1 ns
1-9
100 ps
1-9
1 nF
1 ms
4
100 µs
5
10 µs
6/7
1 µs
7/8
100 ns
1-9
10 ns
1-9
1 ns
1-9
10 nF
10 ms
3
1 ms
4
100 µs
5
10 µs
6/7
1 µs
7/8
100 ns
1-9
10 ns
1-9
100 nF
100 ms
2
10 ms
3
1 ms
4
100 µs
5
10 µs
6/7
1 µs
7/8
100 ns
1-9
1 µF
1 s
1
100 ms
2
10 ms
3
1 ms
4
100 µs
5
10 µs
6/7
1 µs
7/8
10 µF
10 s
1 s
1
100 ms
2
10 ms
3
1 ms
4
100 µs
5
10 µs
6/7
100 µF
100 s
10 s
1 s
1
100 ms
2
10 ms
3
1 ms
4
100 µs
5
1 mF
1 ks
100 s
10 s
1 s
1
100 ms
2
10 ms
3
1 ms
4
10 mF
10 ks
1 ks
100 s
10 s
1 s
1
100 ms
2
10 ms
3
100 mF
100 ks
10 ks
1 ks
100 s
10 s
1 s
1
100 ms
2
1 F
1 Ms
100 ks
10 ks
1 ks
100 s
10 s
1 s
1
Example: for a cell with a capacity of 100 nF with a time constant of 1 ms, studied with a current
range of 100 µA, the recommended bandwidth is the bandwidth number 4.
6.1.2 Bandwidth selection of a channel connected to ULC and/or one booster
The same kind of table can be proposed to help the user select the correct bandwidth when
the channel board is connected with the booster. The selection of the bandwidth can be done
as previously, considering the cell capacity and time constant of the cell.

Bio-Logic SP-240 Specifications

General

Brand	Bio-Logic
Model	SP-240
Category	Measuring Instruments
Language	English