Advanced Measurement Technology 273A, User Manual

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1. INTRODUCTION
1.1. Overview
The Model 273A Potentiostat/Galvanostat features both front-panel and computer control for
virtually unlimited flexibility and utility. It uses the latest analog and microcomputer design
advances to provide high performance, ease of use, and greater versatility in electrochemical
measurements.
The instruments 100 V compliance and 1 A output capability allows rapid and accurate potential
or current control in virtually any electrochemical cell. The high compliance voltage is particularly
important in maintaining potential control when working with high-resistance, dilute electrolytes
or non-aqueous solvents. Moreover, it enables faster charging of the cell capacitance, allowing
the potentiostat to rapidly respond to step transitions in the control potential.
Component selection, shielding, grounding, and circuit design are all carefully optimized for
minimum internal electronic noise, giving high sensitivity and a quiet output signal. A low pass
filter facilitates dealing with noise arising in the cell itself.
The Model 273A uniquely addresses the critical question of stability versus speed. The user can
select a HIGH SPEED mode to take advantage of the potentiostat's extraordinarily fast rise time.
Alternatively, the user can select the HIGH STABILITY mode for oscillation-free operation with
almost any cell.
A high-performance, four-terminal current-to-voltage converter circuit is inducted for accurate,
rapid, low-drift current measurements, free of degradation from cell-cable resistance,
capacitance, and inductance.
The Model 273A uses an external differential electrometer. Not only does this approach further
assure freedom from cell-cable effects, but it allows the use of two reference electrodes to
control the potential across an interface, such as a membrane. In addition, the electrometer can
be configured to provide a remote sensing contact to the working electrode and so eliminate any
potential error resulting from high current in the contact resistance.
1.2. About this Manual
The Model 273A Potentiostat/Galvanostat can be operated either directly with its front-panel
controls or remotely from a personal computer or workstation. This Instruction Manual provides
details of the physical and electrical characteristics of the Model 273A, and describes how to
operate it as a stand-alone instrument controlled from its front panel.
Instructions for operating the unit remotely via either the RS-232C or GPIB (IEEE-488) interface
port are given in the separately bound Model 273A Remote-Programming Command Handbook.
In addition to the command descriptions, the Command Handbook gives detailed explanations of
GPIB (IEEE-488) and RS-232C communications, including rear-panel switch settings,
communications protocols, and some useful communications routines. Also included in the
Command Handbook is an application note on waveform programming„ one of the most useful
functions of the Model 273A.
This Instruction Manual is organized into five chapters and three appendices. Chapter 1 provides
a general description of the Model 273A. Be sure you understand the information in Section 1.4
about the polarity convention used in this instrument.
The 100 V output and high current capability of the Model 273A make it potentially lethal if not
used with care and respect. Chapter 2 describes recommended safety precautions for operating
it. Chapter 2 also explains how to set the instrument for operation with different input power
voltages, replace the power line fuse, and determine whether power is applied to the counter
electrode connector.