Advanced Measurement Technology 273A, Руководство пользователя

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Model 273A Potentiostat/Galvanostat User’s Manual
Warning! For operator and equipment safety, the power should be off when connecting or
disconnecting cables.
on the 1 mA current range (assuming a Log Reference of -3), 1 mA would give 0 V, 100
µA would give -1 V, 10 µA would give -2 V, and so forth.
Currents larger than the Log Reference Range give positive outputs. In the example
being considered, a current of 2 mA would give +0.301 V on the 1 mA range, a current
of 10 mA would give 1 V, and a current of 100 mA would give 2 V.
These relationships hold for both automatic and manual current ranging.
The maximum possible voltage in any case is 10 V. The smallest change is 5 mV (1 part
in 2000).
d. COULOMBS: In this mode, a full-scale current for one second on the current range in
effect when RESET INTEGRAL is pressed will give 10 V out. For example, if, on the
1 mA range, the current was 1 mA for 1 s, the OUTPUT voltage would be 10 V,
representing one millicoulomb of charge. At that point, the output scaling would decrease
by a factor of ten. In the example, after one second, the output would reach 10 V and
then immediately drop to 1 V as the scaling shift occurs. The voltage would then rise
linearly with charge until 10 V was reached again (this time indicating ten
millicoulombs). At that point, another factor-of-ten scaling change would take place, and
the cycle would repeat. This process can repeat as many times as necessary for any
practical experiment. The current integral, in coulombs, can be displayed, if desired, with
continuous updating as the measurement progresses. (Recall that one of the functions of
the [ENTER] key is to control the "bottom line display".)
If anodic to cathodic crossover occurs during the measurement, the coulometer will
reverse direction and downrange if necessary. Current Range changes that occur, either
manual or automatic, will have no effect on the voltage at the OUTPUT connector in
coulometer operation.
For best results, the starting current range, the one in effect when RESET INTEGRAL is
selected, should be that which yields the highest on-scale current reading.
3. [RESET INTEGRAL]: This key causes the final current integral, in coulombs, to be
displayed. At the same time the coulometer is reset to zero and the initial scaling factor,
as set by the selected Current Range, is established. Note: The reset state is maintained
for three seconds or until the [RESET INTEGRAL] key is released, whichever is longer.
At that point charge accumulation begins again.
4. [SET I OFFSET]: This key allows one to specify a current that is internally subtracted
from the cell current. The offset is specified in units of current, and the offset range is ±2
times the full-scale range in effect at the time I OFFSET is set. Note that the offset
function only affects the level at the OUTPUT connector (identically the Y Axis Recorder
Output). It is functional for all three output modes (LINEAR, LOG, and COULOMBS).
The displayed cell current is not affected, unless Override 10 (see Section 5.2.4) is
placed in the YES state.
5.3. Rear Panel
In addition to the ac power/fuse assembly (Chapter 2), there are numerous connectors and two
switch assemblies located on the rear panel (Fig. 8). A brief description of each follows. Pinouts
for the multi-pin connectors are provided in Appendix A.