GLK 3000 Use and care manual

MODEL 3000
DIGITAL CAPACITANCE METER
Operation and Calibration Manual
Serial Numbers
This manual applies directly to instruments with serial
numbers 30700 and up, m ain board assembly
8503000-0-3, revision 3.
Rev. 3.3, 21 January 2007
Copyright 2007
Serial Number: ___________
For technical assistance, contact
GLK INSTRUMENTS
Email: [email protected]
Website: www.glkinst.com

GLK INSTRUMENTS
Rev. 3.3, 21 January 2007
Copyright 2007
2
TABLE OF CONTENTS
Section Page
I. Warranty 3
II. Product Use Restrictions 3
III. Return Material Authorization 3
IV. Specifications 4
V. Description 5
VI. Initial Preparation 7
VII. Operating Instructions 8
VIII. Servicing Information 12
IX. Calibration 14
X. Revisions 15

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I. WARRANTY
GLK Instruments products are warranted against defects in wor kmanship and
materials under normal use and service for one year from date of their shipment by
GLK Instruments, except that component s obtained from other s are warranted only
to the extent of the original manufacturers' warranties, if any. This warranty does not
extend to any products t hat have been repaired or altered by other s. GLK
Instruments' sole liability and the Purchaser 's sole remedy under this warranty are
limited to repairing or replacing defective products. The repair or replacement of
defective products does not extend the wa rranty period. This warranty does not
apply to c omponents or products which by the nature of the applic ations are
consumed in operation or wh ich have a normal life inherently shorter than one year.
Examples of this are batteries, com ponents or products exposed to nuclear
radiation, or used in t he measurement of detection of explosions. GLK Instruments
shall not be liable for consequential damages under any circumstances.
THE FOREGOING WARRANTY AND REMEDY ARE IN LIEU OF ALL OTHER REMEDIES AND
ALL OTHER WARRANTIES, WRITTEN OR ORAL, STATUTORY, EXPRESS, OR IMPLIED,
INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR
PURPOSE.
II. PRODUCT USE RESTRICTIONS
GLK Instruments does not recommend the use of any of its products or the
incorporation of any of its products by second parties in their products in (a) life
support applications where failure or malfunction of the product can be reasonably
expected to cause failure of the life support dev ice or to significantly affect its safety
or effectiveness, (b) any nuclear facility applications which including nuclear reactors
and devices designed or used in con nection with the handling, processing
packaging, preparation, utilization, fabricating, alloying, storing, or dis posal of
fissionable material or waste products, (c) consumer applications where failure or
malfunction of the product can be reasonably expec ted to cause injury, and (d)
applications where failure or malf unction of the product can reasonably be expected
to place the health and safety of the gener al public in jeopardy. GLK Instruments will
not knowingly sell its products for use in such applications unless GLK Instruments
receives in writing satisfactory assurances that (a) the risks of injury or damage have
been minimized, (b) the customer assumes a ll such risks, and (c) the liabilit y of GLK
Instruments is adequately protected under the circumstances.
III. RETURN MATERIAL AUTHORIZATION
In the unlikely event that any of the products of GLK Instruments need repair,
contact GLK Instruments for a return material authorization (RMA) number.

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IV. SPECIFICATIONS
(25 oC unless specified otherwise)
Electrical
Capacitance range: 2.000 pF to 200.0 nF
Resolution: 0.001 pF to 0.1 nF
Display: 3 1/2 digit liquid crystal display (LCD)
Accuracy with or without probes: ± (0.1% of reading + 2 digits)
Measurement frequencies: 24 kHz (2 pF, 20 pF, 200 pF, 2 nF)
2.4 kHz (20 nF)
240 Hz (200 nF)
Charging voltage: 5 V (all ranges)
Offset adjustment: 1.5 pF
Analog output voltage: 0 - 200 mV DC
Analog bandwidth(1) : 1.2 Hz (2 pF), 2.8 Hz (20 pF), 15 Hz (200 pF), 64 Hz
(2 nF, 20 nF, 200 nF)
Source resistance: 1000 ohms (1%)
Reference output voltage: 5.000 V DC
Source resistance: 1000 ohms (1%)
Digital I/O: USB Port 1.1 compliant, optically isolated
Battery: 9 V alkaline (NEDA 1604A)
Auxiliary power: 12 - 14 V DC, 50 mA supply
with 2.1 mm DC power jack
USB port power: Isolated, 4.5V to 5.5V, 300mA
Environmental
Operating Temperature: 0 oC to +50 oC
Storage Temperature: -20 oC to +70 oC
Operating relative humidity: 80% (noncondensing)
Mechanical
Package: Bench top, portable instrument case
with tilt bail
Dimensions: 8.50 x 9.52 x2.44 inches
Net Weight: 2 lbs
Accessories Supplied
Two miniature shielded probes and probe accessories (PN 2110112)
9 V battery (NEDA 1604A)
Operation and Calibration Manual
100 nF Chip Capacitor
Battery eliminator (PN 4001200): input 120 VAC, 60 Hz, 6 W; output 9 VDC, 200 mA; 2.1 mm Plug
Application CD and USB cable
Optional Accessories
International battery eliminator (PN 4001201): input 90 to 264 VAC, 47 to 63 Hz, 18 W, IEC 320 connector;
output 12 VDC, 1.5 A, 2.1 mm Plug. Customer supplies AC cord set, 3-prong IEC 320 to local connection.
(1) Note: wideband option 001 increases bandwidth to ~70 Hz on each range. Wideband option must be
specified at time of order. Bandwidth of each range can be customized at time order.

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V. DESCRIPTION
The Model 3000 Digital Capacitance Meter is the first commercially available low
cost, high accuracy instrument designed ex clusively for the measurement of very
small value capac itors and capacitors wh ose size and shape are not conveniently
handled by conventional sock ets, clamp fixtures, or alligator clip lea ds. This
instrument is particularly useful f or the measurement chip capacit ors whose small
size precludes the use of identifying marks.
The Model 3000 em ploys a unique and pat ented (U.S. Patent No. 4806846)
switched capacitor circuit and a ratio metric measurement technique that eliminates
errors due to stray capacitance t o ground. The patent ed circuit has high common-
mode rejection and eliminates errors due to changes in the refe rence voltage from
temperature, aging, etc. This unique circuit allows the capacitor under measurement
to be remotely connected to the meter via two, miniature, shielded probes or coaxial
cables without affecting the accuracy or resolution of the instrument.
The convenience of using miniature pr obes solves the costly problem of
constructing special t est fixtures and shie lded boxes for the determination of the
capacitance of a vari ety of objects. For example, the Model 3000 with its standard
probes can easily determine the capac itance between the pins of a connector, the
large signal gate capacitanc e of power MOSFETs, the depletion capacitance of
diodes, the capac itance between the traces on a printed circui t board, or even the
static capacitance of microstrip or stripline microwave circ uits. Using ultra-miniature,
shielded probes, very accurate wafer le vel, large signal meas urements of MOS
capacitors are easily obtained.
Miniature, shielded probes are normally supplied with the instrument; however,
the Model 3000, due to its unique c ircuitry, can acc ommodate a large v ariety of
custom built shielded probes, special shielded connectors, or test fixtures. Coarse
and fine of fset adjustment potentiometers are provided on the front panel of the
instrument to compensate for any unshield ed test fixture capacitance up to 1.5 pF.
Capacitors can be remotely connected to the Model 3000 usin g standard coaxial
cables such as RG-223. The Model 3000 maintains its accuracy and resolution wit h
or without probes.
Auxiliary analog outputs of the meter reading (0-200mV ) and reference voltage
(5.000V) are available on the bac k panel. These outputs can be c onnected to digital
voltmeters, plotters, data loggers, comput er data acquisition s ystems, etc. using
standard banana jacks and shielded coaxial cables.
Fully isolated digital I/O is available at the USB port on all new instruments
starting at serial num bers 30024 and up. Older instruments can be upgr aded to
support digital I/O fo r a nominal charge. Contact GLK Instruments for details. The
USB port provides access to the instrum ent’s 24-bit ADC an d range switches.

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Digital I/O support ex tends the resolution and range of the instru ment as sh own in
Table I.
A standard 9 V alkaline or lithium battery powers the Model 3000. Battery life is
approximately 200 hours. An auxiliary DC power jack is provided for powering the
instrument from the battery eliminat or (US version PN 4001200 or optional,
international version PN 4001201). The USB port supplie s isolated power to the
Model 3000 whenever a USB cable is conn ected to a compliant USB port (powered
port) on the host computer. When power ed by the USB port, the Model 3000 is
always on, independent of t he ON/OFF s witch position. Due to the optical and
magnetic isolation of the U SB port from the Model 3000 circuitry, the USB port is
active only when powered from the host computer.
Table I. Extended Range and Resolution at USB Port
Front Panel USB Port
Range
Switch
3 ½ Digit LCD
Meter
Extended
Range
Extended
Resolution
2 pF 1.999 pF 3.0000 pF 0.1 fF
20 pF 19.99 pF 30.000 pF 1 fF
200 pF 199.9 pF 300.00 pF 10 fF
2 nF 1.999 nF 3.0000 nF 0.1 pF
20 nF 19.99 nF 30.000 nF 1 pF
200 nF 199.9 nF 300.00 nF 10 pF

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VI. INITIAL PREPARATION
The Model 3000 (PN 2903000-0) is supplied ready for use with a battery, battery
eliminator, two probes wit h accessories, USB cable, and applic ation CD with USB
port drivers and LabVIEW7 demonstration programs. If the 9 V battery is not
installed, open the battery compartment co ver on the back of the instrument by
removing the two thumbscrews. Connect a 9 V battery to the polarized s nap lead,
clamp the battery to the cover, replace co ver, and secure with t humb screws. If the
instrument is to be s tored for an extended period, remove the battery to prevent
damage from leakage.
*********************************************************
ALWAYS DISCONNECT THE BATTERY ELIMINATOR AND ANY TEST
FIXTURES OR PROBES FROM THE INSTRUMENT WHEN REPLACING THE
BATTERY. BEWARE OF STATIC ELECTRICITY
*********************************************************
The instrument is now ready for use; however, it is recommended to perform the
following initial chec kout to become more familiar with the in strument. Select the
2.000 pF range by depressing the respective front panel s witch. Turn on the
instrument by pressing the ON switch. The liquid crystal display should appear and
settle to a stable reading of ± 0.002 withi n a few seconds. The instrument wa s
adjusted at the factory to read ± 0.002 pF. If the display is not within ± 0.002 pF,
then adjust the OFFSET COAR SE or FINE potentiometers on the front panel of the
instrument. Unpack the two probes, and c onnect each probe to the front panel BNC
connectors. Hold probes at least 6 inches apart and observe the display. The display
should read ± 0.002 pF provided the probes are held stationary. If necessary, adjust
the OFFSET FINE potentiometer to zero the display. Hold the probes tips about 1/10
inch apart. You should observ e a readi ng of approximately 0.015 pF or 15
femtofarads. Place the probes at least 6 in ches apart again and check the zero on
the other ranges by depressing each range switch while observing the display. Next,
measure a 100 nF chip capac itor supplied with the unit. First select the 200 nF
range; second touch each of the metalized ends of the chip capacitor with the probe
tips; and third, read the display. The 100 nF chip capacitor has tolerance of ± 20%.
*******************************************************
CAUTION - ALWAYS DISCHARGE HIGH VOLTAGE CAPACITORS BEFORE
MEASURING TO AVOID DAMAGE TO INSTRUMENT
*******************************************************
You should now be familiar wit h the gener al use of the Model 3000 Digital
Capacitance Meter. For a more detailed discussion of the operation of the Model
3000, refer to the following section.

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VII. OPERATING INSTRUCTIONS
A detailed description of each function of the instrument is given in this section.
The basic functions of the Model 3000 are listed below.
Front Panel:
1) Display, 3 1/2 digit LCD
2) Range switch, 2 pF to 200 nF, push-to-select
3) Power switch, push-ON, push-OFF
4) Cx HIGH input BNC (positive connection, drive)
5) Cx LOW input BNC (negative connection, sense)
6) OFFSET COARSE and FINE potentiometers
Rear panel:
7) 9 V battery compartment
8) Auxiliary DC power jack
9) Analog output jacks, 0 - 200 mV DC
10) Reference voltage output jacks, 5.000 V DC
11) USB port
1) The display is a self-contained 3 1/2 digit LCD digital voltmeter with polarity and
decimal point indic ation. The decimal poi nt is automatically s elected when the
desired range switch is pushed.
2) The range switch is a push-to-select interlocking assembly. Ranges are 2 pF, 20
pF, 200 pF, 2 nF, 20 nF, and 200 nF. A resolution of 0.001 pF or 1 femofarad can be
achieved on the 2 pF range.
3) The power switch is a push-ON and pus h-OFF type. Note that the Model 3000 is
always on, independent of the ON/OFF swit ch position, when powered by the US B
port.
4 & 5) Connection to t he Model 3000 is via the BNC's on the front panel. Normally
the probes supplied with the instrument will be connect ed to these terminals .
However, custom-built shielded probes, connectors, or other special test fixtures can
be connected to these terminals without affe cting the accuracy of the instrument.
The terminal marked (+) or HIGH is the positive drive or charging terminal an d
should be connected to the pos itive terminal of polarized capaci tors. Likewise, the
negative sense terminal (-) or LOW input should be connect ed to the negative
terminal of polarized c apacitors. The HIGH terminal should al ways be connected to
the outer foil, plate, or larger electrode of the capacitor under measurement and t he
LOW terminal to its other electrode to mi nimize noise pickup. In the case of 3-
terminal capacitors, such as calibration standar ds, the shield of the capacit or (i.e. its
third electrode) should be c onnected to the ground shield of the probes. An
alternative is to connect a 3-terminal capac itor to the instrument using coaxia l

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cables. In electrically noisy environments the capacitor under test may requir e
shielding to obtain a stable reading. To maintain accuracy and obtain low noise
readings, connect external shielding to both probe shields.
The Model 3000 uses a combin ation of CMOS and JFET devices to charge and
discharge the capacitor under test; cons equently, voltage transients can damage
these devices and will ca use the instrument to malfunction. All capac itors, but
specifically high voltage and high capacit ance capacitors, must be dischar ged first
before measurement to avoid damage to the instrument.
**********************************************************
DISCHARGE ALL CAPACITORS BEFORE MEASUREMENT TO PREVENT
DAMAGE TO THE INSTRUMENT AND TO PREVENT PERSONAL INJURY
**********************************************************
The drive level that is presented to the capacitor under test from the (+) or HIGH
connection is +5.0 V peak with respect to the (-) or LOW connection or to ground
(shields); thus, a wide range of capacitors that have breakdown voltages as low as 5
V can be measured with the Model 3000 without damaging the capacitor under test.
Avoid capacitors that have leaky dielec tric or high conductance. The Model 3000
cannot measure conductance. Depending on the range, l eaky dielectric capacitors
can produce erroneous readings. Likewise, the depletion capacitance of diodes must
be measured under reverse bias conditions, i. e. HIGH terminal is connect ed to the
cathode, and the LOW terminal is connected to the anode to reverse bias the diode.
6) The O FFSET COARSE and FINE pot entiometers on the front panel of the
instrument are used primarily to com pensate for the capacitance between the
unshielded terminals of test fixtures us ed to measure axial and radial leaded
capacitors. The OFF SET potentiometers can subtrac t up to 1.5 pF of test fixture
capacitance. The OFFSET potentiometers are used also to z ero the instrument on
the 2 pF scale and may be re quired occasionally due to amplifier drift, component
replacement, or operation at elevated temperatures.
7) The 9 V battery is housed in a compartm ent on the rear of the instrument. The
Model 3000 will operate for approximately 200 hours on a 9 V alkaline battery. A low
dropout voltage regulator allows extended use of the batte ry down to a voltage of
about 5.2 V before replacement.
8) The auxiliary DC power ja ck provides the capability of operating the inst rument
continuously from an exter nal power source such as the battery eliminator (PN
4001200). The internal 9 V battery is automatically disconnected from the instrument
when the battery eliminator is connected.
9) The analog output jacks provide a 0 - 200 mV DC s ignal proportional to the
capacitor value under test. The bandwidth of the analog output signal is range

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dependent as shown in Table II. The source resistance of the analog output is 1000
ohms.
Table II. Analog Bandwidth
Range Measurement
Frequency (Hz)
Bandwidth (Hz)
(Standard)
Bandwidth (Hz)
(Option 001)
2 pF 24,000 1.2 67
20 pF 24,000 2.8 71
200 pF 24,000 15 78
2 nF 24,000 64 79
20 nF 2400 64 79
200 nF 240 64 79
10) The instrument's inter nal 5.000 V DC reference volt age is available at the
reference output jacks. Its source resist ance is 1000 ohms. The reference output
voltage is used to pr ovide external ratio m etric capability to remove errors in the
analog output signal due to changes in the reference voltage from temperature and
long term drift. Fo r ratio metric measurements, connect the 5 V reference output to
the external reference input on digital voltme ters, data loggers, etc. that provide for
this option. Alternatively, errors from variations in the reference voltage can be
removed from the analog output signal by calc ulating the ratio of analog output to
the 5 V reference output and multiply ing by the appropriate scale factor. U sing the
external outputs of the Model 3000 with precision digital v oltmeters or data
acquisition systems, capac itors can be measured to 0.05% accuracy and to a
resolution of 10 ppm.
11) USB port provides fully isolated digi tal I/O and po wer, extended resolution and
range as shown in Table I, and powers the M odel 3000 from the host computer. To
access the USB port, the appropriate drivers must be installed on the host computer.
The drivers are available on the application CD-ROM or can be down lo aded from
our website: www.glkinst.com/cmetersoftware. To install the USB drivers on the host
computer, follow the instructions in the file: ReadmeUSBDriverInstall
To demonstrate the basic f eatures of the M odel 3000 digital I/O, load and run
the LabVIEW® demonstration program. This program is availabl e as a sta ndalone
application or VI. The demonstration pr ogram is written in LabVIEW® 7 and
complied with National Instruments' ( www.ni.com) Application Builder. Users without
LabVIEW® 7 can run the applic ation by in stalling the LabVIEW® 7 runtime engine
included on the Model 3000 application CD-ROM.
Note: All s oftware and drivers for the Model 3000 have been tested only on
computers running Microsoft's Windows XP® Professional and Home editions. To
completely install all USB drivers, “found new hardware” will run four times. All of the

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Model 3000 and USB communication VI's were written in LabVIEW® 7 an d will not
run in earlier versions of LabVIE W®. Contact National Instruments, www.ni.com, to
upgrade to version 7 or later, or insta ll the runtime engine a nd run the executable
version of the demonstration program.

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VIII. SERVICING INFORMATION
For service and calibration of the Model 3000 Digital Capacitance Meter, contact
GLK Instruments directly. Complete repair and cali bration services are maintained
by GLK I nstruments; however, minor re pair and calibration can generally be
performed in the fi eld if you have acce ss to a precision 3-terminal capacitor
standard. Location of parts, test points, and adjustments are shown in Figure 1.
The switched capacitor circuit in the Model 3000 us es two JF ET transistors
driven by CMOS logic and an o pamp to convert current to voltage. Circuit protection
from voltage transients is built-in to the switched capacitor circuit; however, failure to
discharge high voltage capacitors or static discharge can damage the circuitry. The
switched capacitor circuit includes these replaceable parts Q3 and Q4 ( 2N5116
JFETS), U3, U4, and U6 (4049 CMOS hex buffers), and U10 (TL061 opamp).
In the event that the switched capacit or circuit is damaged, spare parts are
located inside the Model 3000 on the main board, A0, below the ADC-digital I/O
board (USB interface), A3, if present. T he spare parts include 2-each, 2N5116
JEFTS (Q3 and Q4), 2-each 4049 CMOS hex buffers (U3, U4, or U6), 1-each TL061
opamp (U10), and 1-each 0.125 A fuse (F1) for the external power supply or battery
eliminator. All critical par ts are socketed for easy replacement. JFETS, Q3 and Q4,
should be replaced in pairs.
Basic Diagnostics:
If the Model 3000 fails to power on under ba ttery power, replace the 9 V battery
through the compartment on the back of the ins trument. Remove the two
thumbscrews to gain access to the battery . If the Model 3000 fails to power up when
connected to the battery eliminator but operates normally on battery power, check
the battery eliminator for approximately 12 V between the center pin and outer
conductor and fuse, F1. Replace battery eliminator if defective. To check fuse, open
the Model 3000 by removing t he four sc rews on bottom of the instrument and
remove the top cover. Check fuse with an ohmmeter and replace if open using the
spare fuse. If the Model 3000 still fails to power on, contact GLK Instruments.
If you sus pect that the input circuitry is damaged, first check regulated power
supply voltage between TP2 an d GND for a voltage of 5. 000 ± 0.002 V. If proper
reading is obtained, proceed to the next step. Check t hat a 0 to 5 V s quare wave is
present at the “HIGH” BNC terminal on the front panel. If there is no signal, r eplace
U3 and U4; recheck for square wave. JFET S, Q3 and Q4, are located ins ide the
rectangular metal shield. To gain access to Q3 and Q4, remove the two, 2-56 nuts
on the top of the metal shie ld. Replace both Q3 and Q4, and zero the LCD meter
using the c oarse and fine adjust ments. If unable to z ero, replace U10 adjacent to
Q3 and Q4. Repeat zero adjustment. Attach a 1 nF standard capacitor, and note the
LCD reading. If the reading is 1.00 nF, the Model 3000 is working correctly. Replace

GLK INSTRUMENTS
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the metal shield and calibrate instrument . If the above repair is unsucce ssful, the
instrument will need factory service. Contact GLK Instruments for RMA and shipping
instructions.
Figure 1. Location of parts, test points, and adjustments. Spares are located on the
main board, A0, and under the ADC-digital I/O USB interface board, A3, if present.

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IX. CALIBRATION
Field calibration of t he Model 3000 Digital Capa citance Meter can be
accomplished using only a s ingle 1.000 nF (1000 pF), 3-terminal standard c apacitor
such as General Radio or IET Labs ( www.ietlabs.com) Model 1404-A standard
reference capacitor. Refer to main circuit board, A0, and ADC-digital I/O board (USB
interface), A3, for the location of test points and calibrati on adjustments.
Adjustments and test points are labeled on the printed circuit boards (see Figure 1).
To calibrate the Model 3000, first remove the top half of the instrument case by
removing the four screws located in the bo ttom half of the case. If operating in
battery mode, check the battery voltage at A0TP1. If its voltage is below 7 V, replace
the battery with a fresh 9 V alk aline or li thium cell. The Model 3000 will function
correctly down to a battery voltage of approximately 5.2 V. Note, in the followin g
procedure, the calibr ation standard is assumed to 1.0000 nF ± 0.0001 nF. Your
standard may differ slightly in value; in that case, adj ust the Model 3000 meter
reading to agree with your standard.
Turn on the instrument, measure the vo ltage at A0T P2, and adjust the 5 V
potentiometer, A0R5, to set the voltage at A0TP2 to +5.000 ± 0.002 V. Select the
2.000 pF range and adjust the OFFSET COARSE and FINE potentiometers to zero
the display. The display should read ± 0.0 00 pF after zero adjustment. Select the
2.000 nF range and connect the 1000 pF (1.000 nF) standard capacitor to the
instrument using coaxial cables. Adjust the CAL potentiometer, A0R11, for a disp lay
reading of 1.000 nF ± 0.000 nF.
Connect a calibrated, high im pedance voltmeter, such as the Agilent 34401A, to
the ANALOG OUTPUT terminals on the back of the instrument. The 34401A should
be set as follows: range to 200 mV, resoluti on to fast 6 digit, and input res istance to
>10 Gohm. Adjust the AUX CAL potentiometer, A0R27, for a reading of 0.1000 V ±
0.0001 V.
Connect the Model 3000 USB port to the host computer and run the Model 3000
LabVIEW® demonstration progr am. Adjust AD CAL potentiome ter, A3R7, for a
software display reading of 1.0000 nF ± 0.0001 nF. A3R7 is located on the AD-
digital I/O USB interface board in the approximate position shown in Figure1.
This completes the basic calibration of the instrument. All of the other ranges will
track the calibration on the 2.000 nF range to within ± (0.1% of readin g + 2 digits).
Remove the standard capacitor and replace the cover. The Model 3000 is now ready
for use as precision capacitance meter.

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X. REVISIONS
The following changes are effective for instruments with serial numbers 30000 and
up (PCB Assembly 8503000-0-3 Rev 3).
No revisions at this time. This manual and any future revisions will be posted on our
website: www.glkinst.com