TECHNICAL BULLETIN TB-3090

Static Field Meter & Ionization Test Kit

Operation and Maintenance Made in the
United States of America

The Desco 19443 Air Ionization Test Kit includes and

utilizes the 19442 Digital Static Field Meter to measure
the offset voltage (balance) and charge decay of
ionization equipment. The Air Ionization Test Kit also
includes a charger used to place a ±1000V charge on
the conductive plate, making it possible to also measure
the discharge times of air ionization equipment per ANSI/
ESD SP3.3 Periodic Verification of Air Ionizers.
Although not as accurate, the Desco Air Ionization Test
Kit is designed to make measurements that correspond
to those made by using a charged plate monitor and
ANSI/ESD STM3.1. The Air Ionization Test Kit provides
convenience and portability to test per ANSI/ESD SP3.3
Periodic Verification of Air Ionizers or Compliance
Verification ESD TR53. Desco recommends using the
a Charged Plate Monitor if precise measurements are
Figure 1. Desco 19442 Digital Static Field Meter required.
All Digital Static Field Meters and Air Ionization Test Kits
are calibrated to NIST standards.
“When any object becomes electrostatically charged,
there is an electrostatic field associated with that charge.
If an ESDS (ESD sensitive) device is placed in that
electrostatic field, a voltage may be induced on the
device. If the device is then momentarily grounded, a
transfer of charge from the device occurs as a CDM
(Charged Device Model) event. If the device is removed
from the region of the electrostatic field and grounded
again, a second CDM event will occur as charge (of
opposite polarity from the first event) is transferred from
the device.” (Handbook ESD TR20.20 section 2.7.5 Field
Induced Discharges)
The Digital Static Field Meter, Air Ionization Test Kit,
Figure 2. Desco 19443 Air Ionization Test Kit and its accessories are available as the following item
numbers:
Description Item Description
The Desco 19442 Digital Static Field Meter indicates
19442 Digital Static Field Meter
surface voltage and polarity on objects. The meter has
a measurement range of 0 to ±19.99 kV at a distance of 19443 Air Ionization Test Kit
1 inch and a measurement accuracy of ±5%. It utilizes 19440 Conductive Plate and Charger
a chopper-stablized sensor for use in both normal 19441 Conductive Plate
and ionized environments. The meter’s enclosure is
19864 Replacement Coiled Ground Cord
dissipative and features a 7 mm snap and ground
cord for bonding to equipment ground. A rotary zero
knob sets the zero-reference point with finely tuned
precision, and a Hold button allows the user to “freeze”
a displayed measurement for evaluation. A LED range
indicator assists with placing the meter at the correct
distance from the object being measured.
DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • (909) 627-8178
DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • (781) 821-8370 • Website: Desco.com

TB-3090 Page 1 of 7 September 2024 © 2024 DESCO INDUSTRIES, INC

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 Packaging Features and Components
19442 Digital Static Field Meter Digital Static Field Meter
1 Digital Static Field Meter
1 Coiled Ground Cord, 12' length
1 9V Alkaline Battery

19443 Air Ionization Test Kit

1 Digital Static Field Meter A
1 Conductive Plate
1 Charger B
1 Coiled Ground Cord, 12’ length D
2 9V Alkaline Battery C
1 Carrying Case

19440 Conductive Plate and Charger

1 Conductive Plate
1 Charger
1 9V Alkaline Battery
1 Carrying Case
19441 Conductive Plate
1 Conductive Plate

Figure 4. Digital Static Field Meter features and

components

A. Display: Displays the measured value in kV/inch.

B. Rotary Zero Knob: Sets the 0 volt reference point.
C. Power Switch: Slide to the left to power the meter off.
Slide to the right to power the meter on.
D. Measure/Hold Pushbutton Switch: Press the
pushbutton to display live measurements. Release the
pushbutton to freeze the measurement on the display.
Figure 3. Air Ionization Test Kit and Carrying Case The red LED above the pushbutton will illuminate when
HOLD is enabled.
E. 7 mm Ground Snap: Connect the included 7 mm
coiled ground cord here to ground the meter.
F. Battery Cover: Slide the cover down to open the 9V
battery compartment.

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • (909) 627-8178

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • (781) 821-8370 • Website: Desco.com

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 Charger Operation
Digital Static Field Meter
A NOTE: The Digital Static Field Meter’s enclosure is
conductive. The instrument senses the difference in
potential between the enclosure and the tested surface.
The meter must be grounded by either the hand of a
grounded operator or the included coiled ground cord to
achieve accurate measurements.
Zeroing the Digital Static Field Meter
B Slide the power switch to the right to power the Digital
Static Field Meter. Point the top of the Digital Static
Field Meter approximately 1 inch (2.5 cm) away from
a grounded metal surface. Proper spacing is indicated
when the two red bullseyes emitted LED range indicator
become centered on top of each other. Turn the rotary
zero knob until the Digital Static Field Meter’s display
reads 0.00.

Figure 5. Charger features and components

A. Output Contact: The output contact is connected to

an internal power source. When the touch plate located
Figure 6. Pointing the Digital Static Field Meter to a
underneath the unit is connected to ground, the output
grounded surface
contact will provide a charge of the indicated polarity.
The charger is designed so that an operator can press
the rocker switch and touch the plate simultaneously
with the fingers of the same hand.
B. Rocker Switch: Press and hold to select the polarity
that will be provided at the Output Contact.
C. Touch Plate: Make contact with the touch plate while
pressing down the rocker switch to provide voltage to the
Output Contact. The operator must be properly
grounded during use.
D. Battery Compartment: Slide the cover down to open
the 9V battery compartment.

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • (909) 627-8178

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • (781) 821-8370 • Website: Desco.com

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 Holding the Last Reading
With the Digital Static Field Meter positioned 1 inch
(2.5 cm) from the object being measured, press the
red pushbutton switch into the HOLD position. This will
freeze the measurement on the display and illuminate
the red LED located above the pushbutton switch. This
feature allows the operator to move the Digital Static
Field Meter where it may be more easily read or saved
for later reference.
NOTE: The LED range indicator will disable while the
Digital Static Field Meter is in HOLD mode. Use the
HOLD feature between measurements to prolong the
Figure 7. Aligning the two bullseyes emitted by the LED battery’s life.
range indicator

Performing a Measurement Air Ionization Test Kit

Use the LED range indicator to position the top of the Performing Offset Voltage (Balance) Measurements
Digital Static Field Meter 1 inch (2.5 cm) from the object The Air Ionization Test Kit has been designed to match
to be measured. The Digital Static Field Meter will the
display a reading (from 0 to ±19.99) of the electrostatic compact size and hand held convenience of the Digital
field in kilovolts per inch. Static Field Meter. Use the following procedure to verify
the offset voltage (balance) of air ionization equipment.
NOTE: The display will indicate “1” or “-1” when the
This quick and easy procedure will help determine if
Digital Static Field Meter is over-ranged. Change the
the piece of ionization equipment is working within the
range of the unit if necessary. If the measurement
manufacturer’s specifications or user requirements. It is
exceeds 20 kV, move the Digital Static Field Meter
extremely important that ionizers be checked regularly
farther away from the object and multiply the reading
for offset voltage (balance) and discharge times.
by the distance (in inches) away from the object being
An ionizer operating in an out-of-balance state can
measured. The measurement accuracy is dependent
place a charge on sensitive electronic components or
on a stable ground reference and the 1 inch measuring
assemblies.
distance. It is also dependent on the “aspect ratio”,
relating the size of the object to be measured to the NOTE: The Digital Static Field Meter’s enclosure is
measurement distance. conductive. The instrument senses the difference in
potential between the enclosure and the tested surface.
NOTE: This aspect ratio should be at least 3 for best
The meter must be grounded by either the hand of a
accuracy. In other words, the object should be at least
grounded operator or the included coiled ground cord to
a 3 inch square when measuring at a 1 inch distance.
achieve accurate measurements.
Accurate measurements may be made at other
measurement distances by scaling the Digital Static Installing the Conductive Plate
Field Meter range and observing the proper aspect ratio. The Digital Static Field Meter’s case has two slots
For example, at a measurement distance of 3 inches, along its sides. The top slot is closest to the face of the
multiply the Digital Static Field Meter reading by 3 to instrument. Slide down the tabs of the Conductive Plate
give a range of 0 to 60 kilovolts. For accuracy, the object plate into the top slot of the Digital Static Field Meter’s
being measured at this distance should be at least a 9 case as far as they go.
inch square.

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • (909) 627-8178

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • (781) 821-8370 • Website: Desco.com

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 Figure 9. Using the Digital Static Field Meter with
Conductive Plate to measure the offset voltage of a
benchtop ionizer

Holding the Last Reading

Press the red pushbutton switch into the HOLD position.
Figure 8. Sliding the Conductive Plate onto the Digital This will freeze the measurement on the display and
Static Field Meter illuminate the red LED located above the pushbutton
Zeroing the Digital Static Field Meter switch. This feature allows the operator to move the
Slide the power switch to the right to power the Digital Digital Static Field Meter where it may be more easily
Static Field Meter. Make contact between the top of read or saved for later reference.
the Conductive Plate and a grounded surface. Turn the
Performing Discharge Time Measurements
rotary zero knob until the Digital Static Field Meter’s
In order to verify that an ionizer is operating properly it is
display reads 0.00.
also important that its ability to neutralize or discharge
Performing a Measurement static electricity is measured. The following procedure
Locate the Test Kit in an ionized environment at the will measure an ionizer’s discharge time:
appropriate distance from the device under test. The
Operating the Charger
static field displayed is the actual balance of the ionizer
The Charger has a momentary rocker switch that powers
or voltage offset. The display will indicate “1” or “-1”
the unit. Holding the switch forward / backward supplies
when the Digital Static Field Meter is over-ranged.
power to the output terminals.
Change the range of the unit if necessary.
Polarity Selection
NOTE: When testing pulsed ionizer systems, the voltage
The top of the rocker switch is labeled “+”, and the
displayed is constantly changing. This pulse rate may
bottom is labeled “-”. To provide a POSITIVE voltage
be faster than the display update rate of the Digital
output, touch the plate located underneath the charger,
Static Field Meter, therefore the displayed voltage is an
and press the switch forward at the same time. To
average of the actual voltage. The output of the Digital
provide a NEGATIVE voltage output, touch the plate
Static Field Meter is useful in this situation for more
located underneath the charger, and press the switch
accurate measurements.
downward at the same time.
NOTE: For the Charger to work correctly, the operator
and Digital Static Field Meter must be properly
grounded. A ground path to the touch plate must exist.
Ionizer Discharge Time
Use the Digital Static Field Meter with the Conductive
Plate in the appropriate location for measurements.

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • (909) 627-8178

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • (781) 821-8370 • Website: Desco.com

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 Positive Discharge Time Measurements Maintenance
To provide a POSITIVE voltage output, touch the
The Digital Static Field Meter and Charger are factory
plate located underneath the Charger, and press the
calibrated and no maintenance is required. Contact
switch forward at the same time. Momentarily touch
Desco Customer Service should the products behave
the Charger’s output terminal to the conductive plate
abnormally. Any unauthorized service will void the
attached to the Digital Static Field Meter. The Digital
warranty and result in additional repair charges.
Static Field Meter reads approximately +1.10 kV. By
using a stop watch or other timing device, determine the NOTE: This Digital Static Field Meter is a precision
time needed for the voltages to decrease from +1.10 kV instrument and should not be subjected to dropping as
to +0.10 kV. This is the positive discharge time. that would void the warranty.
Negative Discharge Time Measurements Replacing the Battery
To provide a NEGATIVE voltage output, touch the plate The Digital Static Field Meter’s battery should be
located underneath the Charger, and press the switch replaced when four decimal points appear on its display.
downward at the same time. Momentarily touch the The battery in the Charger should be replaced annually
Charger’s output terminal to the conductive plate or when it is unable to provide approximately ±1100V.
attached to the Digital Static Field Meter. The Digital Always replace the batteries with a 9V alkaline or
Static Field Meter reads equivalent battery.
approximately -1.10 kV. By using a stop watch or other
timing device, determine the time needed for the Cleaning
voltages to decrease from -1.10 kV to -0.10 kV. This is The area around the aperture of the Digital Static Field
the negative discharge time. Meter must be kept clean to ensure accurate, drift-free
readings. Never touch the aperture. Use low-pressure
NOTE: A ground path must be provided between the instrument-grade air to remove dust or other debris. To
touch plate of the Charger and the ground reference of remove more severe contamination, spray or flush with
the Digital Static Field Meter. This is normally provided the smallest practical amount of clean technical-grade
by holding the Charger in one hand and the Digital Static of isopropyl alcohol. Allow the instrument to air dry for
Field Meter with Conductive Plate in the other. several hours afterward.
Keep the insulators on the Aluminum Conductive Plate
clean and free of contaminates that may cause surface
leakage. To test the performance of the Conductive
Plate, charge the plate and note the discharge rate in
a non-ionized area. The self discharge rate to 10% of
original voltage should be greater than five minutes.

Figure 10. Using the Charger to apply a charge onto the

Conductive Plate

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • (909) 627-8178

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • (781) 821-8370 • Website: Desco.com

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 Specifications Air Ionization Test Kit
Digital Static Field Meter Conductive plate Aluminum bracket, bare
Assembly aluminum plate and teflon
Display LCD. 3.5 digit numeric display, spacers isolate plate from
0.375" height. Displays measured bracket
voltage in kV when measurement
distance is 1 inch. Voltage Output 1/10,000 of measured voltage
Range -19.99 kV to +19.99 kV at a Conductive plate Area 2.95" W x 1.18" L
distance of 1 inch (25 mm). Higher (7.5 x 3.0 cm)
voltages may be measured at Conductive plate 2.4 oz. (68 g)
distances greater than 1 inch. Assembly Weight
Accuracy ±5% Charger Dimensions 1.1" H x 2.6" W x 4.5" L
Controls ON/OFF slide switch. MEASURE/ (2.8 x 6.6 x 11.4 cm)
HOLD pushbutton (latching push- Charger Weight 5 oz. (140 g) with battery
ON/push-OFF). ZERO adjustment Charger Power One 9-volt alkaline battery
knob. Requirements
Analog Output 2.5 mm subminiature jack. Scaling Charger Output (using 1.1 kV minimum for ± voltage
is 100 mV per kV. Full scale is -2 V Static Sensor with
to +2 V. conductive plate)
Power 9 VDC alkaline battery. Battery life Certifications CE
in excess of 30 hours. Reversal
protected. Country of Origin United States of America
Size 2.4" W x 4.2" L x 1.3" D
(61 x 107 x 33 mm)
Limited Warranty, Warranty Exclusions, Limit
Weight 5 oz. (14.2 g) with battery
of Liability and RMA Request Instructions
Environmental Operates at 0 to 50° C and 0
to 85% RH (non-condensing). See the Desco Warranty -
Accuracy unaffected by air Desco.com/Limited-Warranty.aspx
ionization.
Certifications CE
Country of Origin United States of America

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • (909) 627-8178

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • (781) 821-8370 • Website: Desco.com

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