Desco 19635 Installation Manual

TECHNICAL BULLETIN TB-2083

Micro Meg™ Pocket Megohmmeter
Operation and Maintenance

Installation

Remove the meter from the carton and inspect for
damage. Each unit should be fully charged and
includes:

1 Micro Meg Pocket Megohmmeter
1 Surface-to-Ground, cord assembly
1 Installed 9V battery

Properly store the megohmmeter and its component
assemblies when not in use.

Operation

The Micro Meg will perform Surface Resistivity

Figure 1. 19635 Micro Meg Pocket Megohmmeter

Description

The Desco 19635 Micro Meg Pocket Megohmmeter
is a portable test instrument designed for measuring
both surface and surface-to-ground resistance of
static dissipative and conductive materials. Seven
color-coded LEDs, read from right to left, easily identify
static dissipative and conductive ranges. The µMeg will
test materials with surface resistivity of 1 x 10E5 to 1 x
10E10. This test instrument is ideally suited for Quality
Control and Field Service personnel as well as for use
in routine auditing of your ESD protective materials.
The Micro Meg features simple one-button operation
and a 9V battery for ease of use and maximum
portability. This auto-ranging instrument weighs only
six ounces. The high-impact plastic case ensures
durability despite the meter’s light weight.

and Surface-to-Ground resistance measurements.
Work surfaces and materials to be tested should be
cleaned prior to testing to ensure that surface dirt and
contamination do not affect results. It is recommended
that non-silicone and non-alcohol based cleaners
such as Desco’s Reztore™ Surface and Mat Cleaner
be used for regular cleaning of ESD protective work
surfaces. When non-ESD surfaces are being used,
Reztore™ Topical Antistat is recommended for
eliminating static charge generation.

Made in America

The Micro Meg has not been designed to meet ESD
S4.1 test equipment requirements and therefore
measurements obtained with this device may not
agree with measurements taken according to the ESD
S4.1 test procedure. This test instrument is intended
for use only as an auxiliary tool for monitoring surface
resistance performance.

If you are interested in obtaining a meter which does
meet all the test equipment requirements of ESD S4.1,
we recommend our model 19780 Surface Resistance
Test Kit. For more information on this product ask for
Techical Bulletin TB-3014.

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • [phone] • Fax [phone]

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • [phone] • Fax [phone] • Web Site: Desco.com

TB-2083 September 2010 Page 1 of 4

Figure 2. Cleaning the work surface before testing.

Surface and Surface-to-Ground resistance readings
are indicated by the series of LEDs on the face of the
meter. The LEDs are read from right to left as follows:

1. RED – Meter is on and battery is functioning

2. GREEN – 5 x 10E10

3. GREEN – 1 x 10E9

4. GREEN – 1 x 10E8

5. GREEN – 1 x 10E7

6. YELLOW – 1 x 10E6

7. YELLOW – 1 x 10E5

© 2010 DESCO INDUSTRIES INC.

Employee Owned

Each LED indicates one order of magnitude of
resistance. If the test surface is conductive to less than
10E5, all the LEDs will be lit. If it is neither conductive
nor static dissipative, only the red “On” LED will be lit.

Surface Resistivity Measurements

Surface resistivity measurements are made using only
the meter without the cord assembly. When the white
button is depressed a test voltage of 9 VDC is applied
to the meter’s center electrode. The second resistivity
electrode will supply the resistance bridge and provide
the measurement. To perform surface resistivity tests,
follow these simple instructions:

Figure 4. Installing Surface-to-Ground cord assembly.

C. Place the Micro Meg on the test surface.

A. Check battery operation by depressing the white
button on the center of the megohmmeter. The red
“On” lamp at the far right should light to indicate that
the unit is functioning properly.

B. Place the meter on the surface being tested. All
three electrodes should make contact with the surface.

C. Press the white button. The surface resistance will
be indicated by the number of LEDs which light up.
The more lights illuminated, the greater the conductivity
of the surface. The measurement is in ohms/square.

WORK SURFACE

Figure 3. Measuring surface resistivity.

Surface-to-Ground Measurements (RTG)

The Surface-to-Ground feature is best used when
expected results are less than 10E6 ohms, and
when residual voltages can be removed from the test
surface. Residual voltages may cause the two upper
range LEDs to light, resulting in a false reading.

When the Surface-to-Ground cord is plugged in,
voltage is diverted from the center electrode to the
cord in order to measure resistance. When making
Surface-to-Ground tests, follow these procedures:

A. Check battery operation by depressing the white
button. The red “On” lamp will indicate that the unit is
functioning properly.

B. Plug the Surface-to-Ground cord into the left side of
the megohmmeter.

D. Connect the test cord to the ground-point for the
surface.

E. Press the white button. The LEDs will indicate the
test results. The measurement is in ohms.

GROUND
POINT

Figure 5. Measuring Surface-to-Ground resistance.

F. Unplug the cord when testing is finished.

Battery Operation

Battery function is automatically checked by the unit
when the meter is turned on. If the battery voltage
drops below 8 VDC, the red LED on the far right of the
meter will not light, indicating a “low battery” condition.
Replace battery with a new 9V alkaline battery.

Maintenance

Your Micro Meg will require very little maintenance,
and there are few user-serviceable parts. If your
meter requires service beyond the simple procedures
described below please contact the factory.

Electrode Cleaning

To assure accurate measurements the electrodes
should be kept as clean as possible. A thorough
cleaning at least every 3 months is recommended. The
following is the recommended cleaning procedure:

1. Carefully remove the electrodes from their
snap-jacks using a screw driver or other blunt flat
bladed object. Avoid scratching or bending electrodes.

TB-2083 Page 2 of 4

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • [phone] • Fax [phone] • Web Site: Desco.com

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • [phone] • Fax [phone]

© 2010 DESCO INDUSTRIES INC.

Employee Owned