Task Masters based on Galvanostats There are a number of options to specify when designing a multiple channel galvanostat based Task Master.

A: Number of channels required.
B: Multiplexed Galvanostat system.
C: Multiple Galvanostat system.
D: Current Control Range of each Galvanostat
E: Electrical Isolation of each Galvanostat.
F: Test Type
G: Read Rate

A: Number of Channels Required.

Each channel can monitor a single cell typically containing 2 or 3 electrodes. Thus in order to polarise 12 test electrodes a 12 channel system is required.

B: Multiplexed Galvanostat system.

A multiplexed system consists of a single galvanostat that is switched between channels. Thus only one channel can be controlled at the same time. The technique is cost effective especially if a complex Galvanostat is required. The same technique is employed with instruments such as the Gill 8 & Gill 12. Channels that are not connected to the galvanostat however are isolated. Thus such a system is not suitable for tests that need to be galvanostatically controlled for a long time period as only one channel is controlled at any one time. 

C: Multiple Galvanostat System

Such a system comprises of a Galvanostat per channel. This enables current control of all channels at all times

D: Current Range of each Galvanostat

A typical single range Galvanostat will give a comfortable current range over four decades. Current ranges up to 7mA are the most cost effective. Each galvanostat can have a wider range of current using switched current ranges. This could be relatively simple in that each Galvanostat has only two current ranges or a wide spread giving a current range from 10pA to 5Amps. The current range needs to be specified by the customer.

E: Electrical Isolation of each Galvanostat

Electrical isolation enables each Galvanostat and thus its associated electrodes to be electrically isolated from the other channels. With electrical isolation electrodes from all Galvanostats can be placed in the same cell at the same time without any externally imposed polarisation between channels. Multiple channel switched Galvanostat systems also offer isolation between channels.

F: Electrical Isolation of each Galvanostat

Any galvanostatic or galvanodynamic test type can be specified with a Task Master. This includes galvanostatic galvanostatic pulse and galvanodynamic sweeps.

G: Read Rate:

The read rate depends on the design of the system and the time constraints of the type of test itself. One reading per minute for each channel is typical for types of test that are quick to monitor such as galvanostatic tests. In a typical cost effective instrument the measurement technology is switched between Galvanostats. However this need not be the case Task Masters can be supplied that perform and monitor more complicated tests on all channels at the same time. 

Examples of Galvanostat based Task Masters.

Gal 15: An instrument for galvanostatic polarisation on all 15 channels fitted with a single current range.

Due to the great variety of these types of instrument we have not supplied pricing information. Please decide what you want using the above information as a guide and ask ACM Instruments for a quotation. Alternatively contact us preferably by 'phone and we will ask the necessary questions and quote to your specifications.