Provided by the ESD Association
Specifying Electrostatic Measurement Tools
With many instruments available for program evaluation, how does one choose effectively?
Q: There are many instruments available for making
electrostatic measurements. What types of equipment do I need to
audit and evaluate my program?
A: Because most material and procedure evaluations
involve charge or voltage generation, resistance or resistivity,
or ground connections, the typical minimum instrumentation requirements
include an electrostatic field meter, a charge plate monitor, a
wide-range resistance meter, a ground/circuit tester, and the appropriate
electrodes and accessories.
Because resistance and resistivity are key
parameters in evaluating many ESD control materials, a wide-range
resistance meter is one of the most critical instruments. It should
be capable of applying both 10 V and 100 V to the materials being
tested. The meter must also be capable of measuring resistance ranges
of 103 to 1012 ,
depending on the resistance range of the materials you typically
Many standard test methods specify test instruments
with open circuit voltages (OCVs). The actual applied voltage of
these instruments may vary with the resistance of the material depending
upon the short-circuit current of the instrument. Be sure you know
the actual applied voltage of the instrument.
For measuring electrostatic charge or voltage,
you will need a handheld electrostatic field meter or a charge plate
monitor. Many field meters simply measure the gross level of electrostatic
charge, and are used as general indicators of the presence of a
charge and its approximate level. A charge plate monitor can be
attached to some field meters for greater precision in facility
measurements or connected to a voltmeter for laboratory evaluation.
Finally you'll need a simple ground/circuit
tester. With this device you can measure the continuity of your
ESD grounds and check the impedance and neutral-to-ground shorts.
Your specific needs are determined by what
you are trying to measure, the required precision, and the sophistication
of your program. Instrumentation requirements for laboratory evaluation
of materials are usually different from those for auditing or monitoring
your program on the factory floor. While some meters are designed
for very precise measurements and typically would be used for laboratory
evaluations, others are less precise, usually designed for portability
and implemented for auditing and monitoring.
In selecting your instrumentation, remember
this: you want the right tool for the job.
Submit your questions to the ESD Help Desk. View other ESD Help Desk topics. Learn more about the ESD Association.
Back to January/February Table of Contents