Trek 325 User Manual
Model 325
High-Sensitivity , DC Stable
Electrostatic Voltmeter
! Measurement Range:
0 to ±40 V DC or Peak AC
!
! Sensitivity: 1 mV
!
! Noise: Less than 1 mV
rms, Referenced to
Measured Voltage
!
! High Seed of Response:
Less Than 3 ms for a
The Trek Model 325 Electrostatic Voltmeter is a versatile
instrument used for performing noncontacting electrostatic
voltage measurements in applications which include
contact potential (surface work function) determination,
materials evaluation and electret studies. The Model 325
was specifically designed for high sensitivity applications to
allo w highly accurate, low noise, no n c o n t acting
measurement of electrostatic voltages of 0 to ±40 V over a
wide range of probe-to-surface distances.
Special features of the Model 325 allow adjusting the
performance of the unit to compensate for specific test
conditions. A calibrated Null Voltage supply of 0 to ±10 volts
nulls measured surface contact potential when measuring
voltages on test surfaces. A response Speed Control adjusts
the AC response of the Model 325. A Drift/Spacing Null
Adjustment minimizes the variation in monitored voltage
values as the probe to test surface spacing changes.
A dual range front panel 3½ digit LED display resolves
±10 mV. The measured voltage can also be monitored
through a precision 1:1 voltage monitor output and/or a
10:1 voltage monitor output.
Trek’s patented low impedance probe sensor assures
measurement accuracy which is essentially independent of
probe-to-test-surface spacing while eliminating the external
environmental effects of high humidity and contamination,
such as airborne dust, toner, ions and chemicals, on
measurement accuracy.
The Model 325 is bench top operable or, with optional
hardware, in a half 9½-inch or standard 19-inch rack.
10 V Step
!
! Voltage Monitor
Accuracy: Better Than
0.05% of Full Scale
!
! Null Voltage Source:
0 to ±10 Volt Calibrated
Supply (nulls measured
surface contact potential
in reference to probe’s
gold sensing electrode)
!
! Drift Spacing/Null
Adjustment (minimizes
measured variations in
voltage as probe to test
surface spacing changes)
!
! Voltage Monitor Outputs:
1:1 and 10:1 of measured
voltage
Measurement and Power Solutions
www.trekinc.com
TM
Model 325 Specifications
All specifications are with a Model PD1216P probe with a probe-to-surface separation of 0.4 mm.
Performance Features (cont.) Features (cont.)
Measurement Range Drift/Spacing Null Adjustment
0 to ±40 V DC or peak AC.
Sensitivity
1 mV.
Accuracy
Voltage Monitor Output
Better than ±0.05% of full scale.
Voltage Display
Better than or equal to ±2 counts,
referred to the voltage monitor.
Speed of Response (10% to 90%)
At Fastest Speed Setting
Less than 3 ms for a 10 V step.
At Slowest Speed Setting
Less than 5 ms for a 10 V step.
Noise (typical)
Less than 1 mV rms,
referenced to measured voltage.
Stability
Drift with Time
Less than 50 ppm/hour,
noncumulative.
Drift with Temperature
1:1 monitor output
Less than 50 ppm/°C.
10:1 monitor output
Less than 100 ppm/°C.
Features
Null Voltage Source
A calibrated 10-turn dial representing a
0 to ±10 volt supply with switch
selectable polarity, is used to produce
zero volts output when the probe is
coupled to a known zero volt surface.
It is also used to null contact potentials
on measured surfaces relative to the
probe’s gold sensitive reference
electrode.
Range
±10 volts
Accuracy
1%
Resolution
10 mV.
This back panel adjustment
minimizes the variation in monitored
voltage values as the probe to test
surface spacing changes.
Voltage Display
3½ digit LED display.
Range
Switch selectable for ±10 V
or ±40 V full scale.
Resolution
10 V Range
0.01 V.
40 V Range
0.1 V.
Zero Offset
±2 counts, referred to the
voltage monitor.
Sampling Rate
3 readings per second.
Voltage Monitor Output (1:1)
A buffered 0 to ±40 V output
provides a replica of the measured
voltage.
Scale Factor
1:1 of the measured voltage.
Output Noise
Less than 1 mV rms
(measured using the true
rms feature of the Hewlett
Packard Model 34401A
digital multimeter).
Output Current
5 mA minimum.
Output Impedance
100 W, nominal.
Voltage Monitor Output (10:1)
A buffered 0 to ±4 V output
providing a replica of the
measured voltage.
Scale Factor
10:1 of the measured voltage
Output Current
5 mA minimum.
Output Impedance
0.1 W, nominal.
Response Speed Control
A front panel potentiometer that adjusts
the AC response of the Model 325.
Probe
During operation, the metallic surfaces of
the probe are driven to voltage levels
equal to the measured surface voltage
value, therefore, the probe holding fixture
must be of an insulating material of
approximately 10 to 10 ohms/square.
Phenolic or other dissipative type material
is recommended to avoid any fixture
charge retention.
Probe-to-Surface Separation
0.2 mm to 2 mm (recommended).
Model PD1216P Sensor Probe
Aperture Orientation
Side viewing.
Aperture Size
4.6 mm (0.18").
Probe Body Type
Round body.
Dimensions
10 mm Diameter x 56 mm L
(0.4" Diameter x 2" L).
Probe Cable Length
2743 mm ±127 mm (9 ft ±5").
7 11
General
Dimensions
108 mm H x 223 mm W x 370 mm D
(4.25² H x 8.75² W x 14.5² L).
Weight
3.6 kg (8 lb).
Voltage Monitor Connector
BNC connector.
Ground Receptacle
Banana jack.
AC Line Cord Receptacle
Standard three-prong line cord with
integral fuse holder.
Line Supply
90 to 127 V AC at 48 to 63 Hz
(optionally available at 180 to 250 V AC
at 48 to 63 Hz).
Copyright ã 2011 TREK, INC.
All specifications are subject to change.
1122/DEC
Model 325 Ordering Information Trek Certification
Item Part No.
Model 325-L (90 to 127 V AC) . . . . . . . . . . . . . . . . . . . . . . 325-L-CE
Model 325-H (180 to 250 V AC) . . . . . . . . . . . . . . . . . . . . . 325-H-CE
Probe
Model PD1216P High-Sensitivity Probe . . . . . . . . . . . . . . . PD1216P
TREK, INC. • 190 Walnut Street • Lockport, NY 14094 • USA • 800-FOR TREK
(fax) • www.trekinc.com • sales@trekinc.com 716-438-7555 • 716-201-1804
TREK, INC. certifies that each Model 325 is tested and
calibrated to specifications using measurement equipment
traceable to the National Institute of Standards and
Technology or traceable to consensus standards.
Loading...