TB-3090
Page 6 of 8
Positive Discharge Time Measurements
To provide a POSITIVE voltage output, touch the
plate located underneath the Charger, and press the
switch forward at the same time. Momentarily touch
the Charger’s output terminal to the conductive plate
attached to the Digital Static Field Meter. The Digital
Static Field Meter reads approxi1.10 kV. By
using a stop watch or other timing device, determine the
time needed for the voltages to decrease from +1.10 kV
to +0.10 kV. This is the positive discharge time.
Negative Discharge Time Measurements
To provide a NEGATIVE voltage output, touch the plate
located underneath the Charger, and press the switch
downward at the same time. Momentarily touch the
Charger’s output terminal to the conductive plate
attached to the Digital Static Field Meter. The Digital
Static Field Meter reads
approximately -1.10 kV. By using a stop watch or other
timing device, determine the time needed for the
voltages to decrease from -1.10 kV to -0.10 kV. This is
the negative discharge time.
NOTE: A ground path must be provided between the
touch plate of the Charger and the ground reference of
the Digital Static Field Meter. This is normally provided
by holding the Charger in one hand and the Digital Static
Field Meter with Conductive Plate in the other.
Maintenance
The Digital Static Field Meter and Charger are factory
calibrated and no maintenance is required. Contact
Desco Customer Service should the products behave
abnormally. Any unauthorized service will void the
warranty and result in additional repair charges.
NOTE: This Digital Static Field Meter is a precision
instrument and should not be subjected to dropping as
that would void the warranty.
Replacing the Battery
The Digital Static Field Meter’s battery should be
replaced when a battery symbol appears on the display.
The battery in the Charger should be replaced annually
or when it is unable to provide approximately ±1100V.
Always replace the batteries with a 9V alkaline or
equivalent battery.
Cleaning
The area around the aperture of the Digital Static Field
Meter must be kept clean to ensure accurate, drift-free
readings. Never touch the aperture. Use low-pressure
instrument-grade air to remove dust or other debris. To
remove more severe contamination, spray or flush with
the smallest practical amount of clean technical-grade
of isopropyl alcohol. Allow the instrument to air dry for
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
Test Equipment Depot - 800.517.8431 -
5 Commonwealth Ave,
Woburn,
MA 01801
