Advanced Measurement Technology 273A, Руководство пользователя

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10
Model 273A Potentiostat/Galvanostat User’s Manual
environments to be so severe as to make reliable operation uncertain. High-level transients are
of three general types.
1. Static Discharge: Transients from this source generally affect input or output circuits. Input
circuits that include MOS field-effect transistors to achieve a high input impedance are
particularly susceptible to damage from this source. Damage typically occurs when the
charge built up on a user's body discharges into an input or output connector as a connection
is being made. Among the factors determining the tendency for charges to build are the kind
of clothing fabrics worn, shoe materials, and the materials in the floor or floor covering.
2. High Level Transients Generated Internal to the Place of Use: Such transients almost
always enter the instrument via the line cord. Possible sources include heavy-duty electric
motors, rf equipment, lasers, diathermy machines, arc welders, spark chambers, and others.
3. Lightning: Unless the equipment is connected to remote sensors, or other devices so
located as to be vulnerable to lightning strikes, transients caused by lightning almost always
enter the instrument via the line cord.
Static discharge problems can sometimes be avoided by judiciously selecting the floor
covering in the work area. The simplest approach to the problem is to discharge one's body
by touching a grounded metal object just before touching the instrument, particularly when
making connections to it. Transients that enter the instrument via the line cord can generally
be suppressed by external line-transient filters. Suitable devices are commercially available.