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Automatic LCR Meter 7330


Instruction/Service Manual



Part No. 9H7330




This instrument has been manufactured by:
Wayne Kerr Electronics Ltd
Durban Road, Bognor Regis, West Sussex, England PO22 9RL
Tel +44 (0) 01243 825811 · Fax +44 (0) 01243 824698
Ver 2.0 · 17 June 1998
© Wayne Kerr Electronics Ltd 1998

The copyright in this work is Vested in Wayne Kerr Electronics Ltd and this document is issued for the purpose only for
which it is supplied. No licence is implied for the use of any patented feature. It must not be reproduced in whole or in
part, or used for tendering or manufacturing purposes except under an agreement or with the consent in writing of and
then only on the condition that this notice is included in any such reproduction. Information furnished is believed to be
accurate but no liability in respect of any use of it is accepted by Wayne Kerr Electronics Ltd.
CONTENTS
1. SAFETY ......................................................................................................................................................... 1­1
1.1 GENERAL........................................................................................................................................................ 1­1
1.2 A.C. POWER SUPPLY ...................................................................................................................................... 1­2
1.3 ADJUSTMENT, REPLACEMENT OF PARTS, MAINTENANCE AND REPAIR ........................................................... 1­2
1.4 STATIC ELECTRICITY ...................................................................................................................................... 1­3

2. SCHEDULE OF EQUIPMENT ................................................................................................................... 2­1

3. INSTALLATION........................................................................................................................................... 3­1
3.1 SUPPLY VOLTAGE ........................................................................................................................................... 3­1
3.1.1 Safety...................................................................................................................................................... 3­1
3.1.2 Changing the Mains Voltage Setting ..................................................................................................... 3­1
3.1.3 Changing the Mains Frequency Setting................................................................................................. 3­2

4. GENERAL INFORMATION....................................................................................................................... 4­1
4.1 INTRODUCTION ............................................................................................................................................... 4­1
4.1.1 Purpose .................................................................................................................................................. 4­1
4.1.2 Test Frequencies .................................................................................................................................... 4­1
4.1.3 Transistor and Diode Measurements ..................................................................................................... 4­1
4.1.4 Bias Voltage ........................................................................................................................................... 4­1
4.1.5 Range Switching..................................................................................................................................... 4­1
4.1.6 Binning of Components.......................................................................................................................... 4­1
4.1.7 Remote Control ...................................................................................................................................... 4­2
4.1.8 Terminals ............................................................................................................................................... 4­2
4.1.9 Kelvin Clip Leads................................................................................................................................... 4­2
4.1.10 Component Fixture 1006 ..................................................................................................................... 4­2
4.2 SPECIFICATIONS .............................................................................................................................................. 4­2

5. USER INSTRUCTIONS ............................................................................................................................... 5­1
5.1 VENTILATION ................................................................................................................................................. 5­1
5.2 MEASUREMENT CONNECTIONS....................................................................................................................... 5­1
5.3 INITIAL SETTINGS. .......................................................................................................................................... 5­1
5.4 TRIMMING. ..................................................................................................................................................... 5­2
5.4.1 Using the Optional Kelvin Clip-Leads for Trimming............................................................................. 5­2
5.5 UNKNOWN COMPONENT TESTS. ..................................................................................................................... 5­2
5.6 TEST FREQUENCY SELECTION. ....................................................................................................................... 5­3
5.7 RESISTANCE MEASUREMENT.......................................................................................................................... 5­3
5.8 INDUCTANCE MEASUREMENT. ....................................................................................................................... 5­4
5.8.1 Measurement of Q Factor & Loss Resistance ........................................................................................ 5­4
5.8.2 Measuring Small Value Inductors.......................................................................................................... 5­4
5.8.3 Measuring Iron-Cored Inductors........................................................................................................... 5­4
5.9 CAPACITANCE MEASUREMENT. ........................................................................................................... 5­6
5.9.1 Measurement of D Factor & Loss Resistance ........................................................................................ 5­6
5.9.2 Measuring Small Value Capacitors ....................................................................................................... 5­7
5.9.3 Measuring Electrolytic Capacitors ........................................................................................................ 5­7
5.9.4 Charged Capacitor Protection............................................................................................................... 5­8
5.9.5 Semiconductor Junction Capacitance.................................................................................................... 5­8
5.10 DEVIATION READOUT. .................................................................................................................................. 5­8
5.11 CONTINUOUS/SINGLE-SHOT MEASUREMENTS. ............................................................................................. 5­8
5.12 RANGE SELECTION........................................................................................................................................ 5­9
5.13 HOLD FACILITY........................................................................................................................................... 5­11
5.14 DISPLAY CHARACTERISTICS........................................................................................................................ 5­11
5.14.1 General............................................................................................................................................... 5­11
5.14.2 Negative Reactance ............................................................................................................................ 5­11
5.15 BINNING...................................................................................................................................................... 5­11
5.15.1 General............................................................................................................................................... 5­11
5.15.2 Keying Errors..................................................................................................................................... 5­13
5.15.3 Sorting by % Deviation. ..................................................................................................................... 5­13
5.15.4 Sorting by Absolute value................................................................................................................... 5­17
5.15.5 Revision and Correction of Entries .................................................................................................... 5­19
5.15.6 Displayed Messages. .......................................................................................................................... 5­20
5.16 GPIB OPERATION ....................................................................................................................................... 5­21
5.17 HIGH SPEED OPERATION ............................................................................................................................. 5­21
5.17.1 Selection ............................................................................................................................................. 5­21
5.17.2 De-selection........................................................................................................................................ 5­21

6. GENERAL THEORY OF OPERATION.................................................................................................... 6­1
6.1 HANDLER INTERFACE. .................................................................................................................................... 6­1
6.1.1 Operation ............................................................................................................................................... 6­1
6.1.2 Interface Details..................................................................................................................................... 6­1
6.1.3 External Trigger..................................................................................................................................... 6­3
6.1.4 Output Drive Levels. .............................................................................................................................. 6­4
6.2 SERIES/PARALLEL EQUIVALENT CIRCUITS...................................................................................................... 6­4
6.3 HIGH SPEED OPERATION ................................................................................................................................. 6­6
6.3.1 Selection ................................................................................................................................................. 6­6
6.3.2 De-selection............................................................................................................................................ 6­6
6.4 GENERAL PURPOSE INTERFACE BUS (GPIB)....................................................................................... 6­6
6.4.1 IEEE Std 488-1978................................................................................................................................. 6­6
6.4.2 Command and Data Formats................................................................................................................. 6­7
6.5 SYSTEM DESCRIPTION........................................................................................................................... 6­17
6.5.1 Microprocessor Control ....................................................................................................................... 6­17
6.5.2 Basic Measurement .............................................................................................................................. 6­17
6.5.3 Overall System...................................................................................................................................... 6­18
6.5.4 Digital Circuits..................................................................................................................................... 6­20
6.5.5 Analog Circuits .................................................................................................................................... 6­21
6.5.6 Autoranging ......................................................................................................................................... 6­22
6.5.7 Interrupts.............................................................................................................................................. 6­22
6.5.8 GPIB Board.......................................................................................................................................... 6­22

7. MAINTENANCE........................................................................................................................................... 7­1
7.1 CLEANING ....................................................................................................................................................... 7­1
7.2 SAFETY CHECKS ............................................................................................................................................. 7­1
7.2.1 Equipment required................................................................................................................................ 7­1
7.2.2 Tests........................................................................................................................................................ 7­1
7.3 POWER SUPPLY AND PERFORMANCE CHECKS ................................................................................................ 7­1
7.3.1 Test Equipment Required ....................................................................................................................... 7­1
7.3.2 Dismantling ............................................................................................................................................ 7­2
7.3.3 Power Supply Checks............................................................................................................................. 7­2
7.3.4 Source Sine Wave................................................................................................................................... 7­3
7.3.5 Measure Frequency................................................................................................................................ 7­3
7.3.6 Bias ........................................................................................................................................................ 7­4
7.3.7 Reassembling ......................................................................................................................................... 7­4
7.3.8 Performance Checks .............................................................................................................................. 7­4
7.3.9 Troubleshooting ..................................................................................................................................... 7­8

8. COMPONENT SCHEDULES...................................................................................................................... 8­1

9. CIRCUIT DIAGRAMS................................................................................................................................. 9­1

10. SUPPORT AND SERVICES .................................................................................................................... 10­1
10.1 GUARANTEE ............................................................................................................................................... 10­1
10.2 MAINTENANCE ........................................................................................................................................... 10­1




ILLUSTRATIONS
Automatic LCR Meter 7330
Fig 4­1 Protection Graph.....................................................................................................................4­4
Fig 4­2 Accuracy Graphs.....................................................................................................................4­6
Fig 5­1 Keypad ....................................................................................................................................5­1
Fig 5­2 Circuit Arrangement for Energizing Inductors.......................................................................5­5
Fig 5­3 Minimum Shunt Load Impedance for 1% Loss of Accuracy .................................................5­6
Fig 5­4 Bias Circuit for Capacitors .....................................................................................................5­7
Fig 5­5 Impedance Chart ...................................................................................................................5­10
Fig 6­1 Interface Lines ........................................................................................................................6­1
Fig 6­2 External Trigger Circuit..........................................................................................................6­4
Fig 6­3 Series/Parallel Equivalent Circuits .........................................................................................6­5
Fig 6­4 GPIB Command Syntax..........................................................................................................6­8
Fig 6­5 Basic Measurement...............................................................................................................6­17
Fig 6­6 Block Diagram......................................................................................................................6­19
Fig 6­7 Timing Waveforms ...............................................................................................................6­23
Fig 7­8 Troubleshooting Chart (Start).................................................................................................7­8
Fig 7­9 Troubleshooting Chart (Power Supply Test)..........................................................................7­9
Fig 7­10 Troubleshooting Chart (Display Assembly Test) ...............................................................7­10
Fig 7­11 Troubleshooting Chart (Main Board Assembly Test) ........................................................7­11
Fig 7­12 Troubleshooting Chart (GPIB (IEEE) Board Test) ............................................................7­12
Automatic LCR Meter 7330
Automatic LCR Meter 7330 · 9H7330 · Ver 2.0 1­1



1. SAFETY

1.1 General
This equipment has been designed to meet the requirements of EN61010 `Safety requirements
for electrical equipment for measurement, control & laboratory use', and has left the factory in
a safe condition.
The following definitions in EN61010-1 apply to this manual:
OPERATOR Person operating equipment for its intended purpose.
Note: The OPERATOR should have received training
appropriate for this purpose.
RESPONSIBLE BODY Individual or group responsible for the use and maintenance of
equipment and for ensuring that operators are adequately trained.
The RESPONSIBLE BODY must ensure that this equipment is used only within its specified
operating conditions. These include environmental, electrical, installation and operating
conditions.
This equipment is intended for use by suitably trained and competent persons only.
This equipment can cause hazards if not used in accordance with these instructions. Read them
carefully and follow them in all respects.
This instrument is not intended for use in atmospheres which are explosive, corrosive or
adversely polluted (e.g. containing conductive or excessive dust). It is intended for indoor use
only.
If it is likely that protection against a hazard has been impaired, e.g. there is mechanical
damage, do not continue to use the equipment. In this situation, the instrument must be made
inoperative and secured against any unintentional operation. The manufacturer should then be
contacted at the address given at the front of the manual to obtain the appropriate procedure to
follow.
Do not use the equipment if it is damaged. In such circumstances the equipment must be
made inoperative and secured against any unintentional operation.


WAYNE KERR ELECTRONICS LTD and the associated sales organizations accept no
responsibility for personal or material damage, nor for any consequential damage that
results from irresponsible or unspecified operation, or any misuse, of this instrument.
1­2 Automatic LCR Meter 7330 · 9H7330 · Ver 2.0

1.2 A.C. Power Supply
Power cable and connector requirements vary between countries. Always use a cable that
conforms to local regulations, terminated in an IEC320 connector at the instrument end.
If it is necessary to fit a suitable AC power plug to the power cable, the user must observe the
following colour codes:


WIRE EUROPEAN N. AMERICAN
LIVE BROWN BLACK
NEUTRAL BLUE WHITE
EARTH GREEN/YELLOW GREEN

The user must also ensure that the protective earth lead would be the last to break should the
cable be subject to excessive strain.
If the plug is fused, a 3A fuse should be fitted.
If the power cable electrical connection to the AC power plug is through screw terminals then,
to ensure reliable connections, any solder tinning of the cable wires must be removed before
fitting the plug.
Before switching on the equipment, ensure that it is set to the voltage of the local AC power
supply.


WARNING!
Any interruption of the protective earth conductor inside or outside the equipment or
disconnection of the protective earth terminal is likely to make the equipment dangerous.
Intentional interruption is prohibited.


1.3 Adjustment, Replacement of Parts, Maintenance and Repair
When the equipment is connected to the local AC power supply, internal terminals may be live
and the opening of the covers or removal of parts (except those to which access can be gained
by hand) is likely to expose live parts.


WARNING!
The equipment must be disconnected from all voltage sources before it is opened for any
adjustment, replacement, maintenance, or repair.


Capacitors inside the equipment may still be charged even if the equipment has been
disconnected from all voltage sources.
Any adjustment, maintenance, or repair of the opened equipment under voltage must be carried
out by a skilled person who is aware of the hazards involved.
Servicing personnel should be trained against unexpected hazards.
Ensure that only fuses with the required rated current and of the specified type are used for
replacement. The use of makeshift fuses and short-circuiting of fuse holders is prohibited.
Automatic LCR Meter 7330 · 9H7330 · Ver 2.0 1­3


1.4 Static Electricity
The unit supplied uses static sensitive devices and service personnel should be alerted to
components which require handling precautions to avoid damage by static electrical discharge.
Before handling circuit board assemblies containing these components, personnel should
observe the following precautions:
1) The work surface should be a conductive grounded mat.
2) Soldering irons must be grounded and tools must be in contact with a conductive surface to
ground when not in use.
3) Any person handling static sensitive parts must wear a wrist strap which provides a leaky
path to ground, impedance not greater than 1M.
4) Components or circuit-board assemblies must be stored in or on conductive foam or mat
while work is in progress.
5) New components should be kept in the suppliers packaging until required for use.
Automatic LCR Meter 7330 · 9H7330 · Ver 2.0 2­1



2. SCHEDULE OF EQUIPMENT
The instrument has been carefully packed to prevent damage in transit.
The complete equipment comprises:-


Description WK Part Number Qty
Automatic LCR Meter 7330 1EV7330 1
Instruction/Service Manual 9H7330 1

Detachable AC Power Cord HC22V2 1




Accessories WK Part Number
Kelvin Clip Leads 5-385-5724
Component Fixture 1006 1EV1006




Note: In the event of damage in transit or shortage in delivery, separate notices in writing
should be given to both the carriers and Wayne Kerr Electronics Limited, within three
days of receipt of the goods, followed by a complete claim within five days. All goods
which are the subject of any claim for damage in transit or shortage in delivery should be
preserved intact as delivered for a period of seven days after making the claim, pending
inspection or instructions from Wayne Kerr Electronics Ltd., or an agent of this
company.
Automatic LCR Meter 7330 · 9H7330 · Ver 2.0 3­1



3. INSTALLATION

3.1 Supply Voltage
Normally, instruments are supplied to suit local power supplies: 230V, 50Hz or 115V, 60Hz. A
label on the rear of the instrument shows the settings made at the time of despatch. The front-
panel fuse ratings are:
230V AC operation 160mA-T
115V AC operation 315mA-T


If the voltage or frequency settings are changed, corresponding changes must be made to the label
and to the fuse fitted. The power lead supplied with the instrument normally has the appropriate
plug, to suit local AC supplies, moulded on. If for any reason the plug has to be replaced, the
connections should be as follows:


WIRE EUROPEAN N. AMERICAN
LIVE BROWN BLACK
NEUTRAL BLUE WHITE
EARTH GREEN/YELLOW GREEN

If the plug is fused, a 3A fuse should be fitted. The power on/off switch is on the front panel. The
instrument is not suitable for battery operation.

3.1.1 Safety
Voltage and/or frequency change-over must be undertaken only by qualified engineers and the
instrument must be totally disconnected from the supply during the conversion. It is the
responsibility of the user to ensure that warning labels on the instrument are amended as necessary
to meet local safety legislation, usually dependent upon national standards.

3.1.2 Changing the Mains Voltage Setting
Perform the following to change the mains voltage setting:
1) Remove the power connector from the rear and turn the instrument base uppermost.
2) Remove two screws from each side of the base cover and remove it.
3) Attached to the transformer is a two-position slide switch with a reversible cover plate.
Remove the plate, set the switch to the required position and re-fit the plate, to show the
new voltage selected.
4) Refit the base cover with the ventilation slots towards the front of the instrument.
5) Change the fuse to the rating listed in section 3.1.
3­2 Automatic LCR Meter 7330 · 9H7330 · Ver 2.0


Note:
On some instruments, the change-over switch is not fitted. To change the mains voltage setting on
these models, perform the following:
Wire the two sections of the split primary in series for 230V AC operation.
Wire the two sections of the split primary in parallel for 115V AC operation.


CAUTION!
It is ESSENTIAL that the relative sense of the two sections is correct. Failure to observe
this will cause the supply to blow.



3.1.3 Changing the Mains Frequency Setting
Perform the following to change the mains frequency setting:
1) Remove the power connector from the rear of the instrument and remove the top cover
(two screws each side).
2) Remove the ribbon-cable connection from PL06 on the main PCB (this is the narrower
ribbon-cable from the front panel). This will expose the two connection points of LK1 on
the board. The mains frequency setting is selected as follows:


60Hz Operation LK1 Link Fitted
50Hz Operation LK1 Link Not Fitted


3) Replace the ribbon-cable connector and re-fit the top cover.
Automatic LCR Meter 7330 · 9H7330 · Ver 2.0 4­1



4. GENERAL INFORMATION

4.1 Introduction

4.1.1 Purpose
The Automatic LCR Meter 7330 is designed for use in GPIB-controlled systems to provide
accurate measurement and sorting of inductors, capacitors and resistors. It is largely immune to
the presence of supply-borne noise and is exceptionally well protected against damage or
malfunction from the connection of charged capacitors. Although intended primarily for
operation with component handling and binning equipment, the 7330 can be used as a stand-
alone instrument for automatic measurement of the major and minor terms of components to
laboratory standards.

4.1.2 Test Frequencies
Three alternative test frequencies are provided, with push-button selection. Measured values of
L, C and R, and the Q factor of inductors or dissipation factor D of capacitors, are shown on a
five-digit LED display with LED indication of the appropriate units for direct readout. The
7330 selects the more usual presentation of results (equivalent series or parallel terms)
according to the impedance value measured, but users can select the alternative presentation if
required.

4.1.3 Transistor and Diode Measurements
To provide for dependable measurements of transistor and diode junction capacitances, a drive
signal level of only 250mV rms, from a 100 source, is used.

4.1.4 Bias Voltage
Provision is made for the application of a bias voltage for polarizing electrolytic capacitors
while they are measured.

4.1.5 Range Switching
Range switching is automatic, with a Range Hold facility available and manual range selection
provided for. Users can also select either a continuous (repetitive) mode of operation or single-
shot measurements. Open-circuit and short-circuit trimming are simply key-press operations:
the appropriate corrections are established automatically, held in non-volatile memory, and
applied by the instrument before any value is displayed. All L, C and R measurements can be
displayed as absolute values or as % deviation from a specified nominal value.

4.1.6 Binning of Components
Comprehensive facilities are provided for the binning of components, by % deviation from a
nominal value or by absolute value, with ten bins available for each method. The selection
process includes an initial check on the Q factor of inductors, or the D factor of capacitors, in
each case to an acceptable limit set by the operator.
4­2 Automatic LCR Meter 7330 · 9H7330 · Ver 2.0

4.1.7 Remote Control
GPIB to IEEE 488 Standard allows the 7330 to be remote-controlled on all functions and
provides for the connection of handlers, binning systems and printers.

4.1.8 Terminals
Four-terminal connection for all measurements virtually eliminates the effect of test lead
impedances, while the availability of a fifth connection - guard - can be used to simplify in-situ
measurements by neutralizing the effect of unwanted shunt impedances.

4.1.9 Kelvin Clip Leads
Kelvin Clip leads are available as an accessory for accurate low-impedance measurements
under laboratory conditions.

4.1.10 Component Fixture 1006
Component Fixture 1006 is available as an accessory for use with the 7330. It has spring-loaded
jaws providing four-terminal connections to components with radial or axial leads. The spacing
between the two pairs of jaws can be adjusted to suit components of all normal sizes.

4.2 Specifications
In step with rapidly developing technology, the company is continually improving its products and
therefore reserves the right at any time to alter specifications or designs without prior notice.

SAFETY
Designed to meet the requirements of EN61010-1.



EMC
This instrument is CE marked demonstrating compliance to EU directive 89/336/EEC (EMC
Directive) as amended by 93/68/EEC (CE Marking Directive). It has been designed to comply with
EN50081-1:1992 for emissions and EN50082-1:1992 for immunity.
RF IMMUNITY When the instrument is being used in a 3V/m field, a
(AS TESTED TO IEC 801-3) permissible loss of performance of typically 3% may be
reasonably expected. The instrument is considered as
satisfying Performance Criterion A of EN50082-1 under these
conditions.



OVERALL DIMENSIONS
WIDTH 483mm (19in)
HEIGHT (inc feet) 136mm (5.4in)
DEPTH 452mm (17.8in)
WEIGHT 9.5kg (21Ib)
Automatic LCR Meter 7330 · 9H7330 · Ver 2.0 4­3




MAINS INPUT
INPUT VOLTAGE 115VAC ±10% or 230VAC ±10% (selectable)
FREQUENCY 50/60Hz (selectable)
INPUT POWER 25VA max
INPUT FUSE RATING 115V Operation 315mA `T' type
230V Operation 160mA `T' type
The input fuse is located in the fuseholder on the front panel
above the input power switch.


ENVIRONMENTAL CONDITIONS
TEMPERATURE RANGE:
Storage -20°C to +60°C -4°F to + 140°F
Operating 0°C to +50°C +32°F to +122°F
Full Accuracy +10°C to +30°C +50°F to +86°F
ALTITUDE Up to 2000m
RELATIVE HUMIDITY Up to 80% non-condensing
INSTALLATION CATEGORY (in accordance with IEC664)
POLLUTION DEGREE 2 (in accordance with IEC664)



PERFORMANCE
MEASUREMENT FUNCTIONS L, C, R, Q, D percentage deviation and auto component
mode.
MEASUREMENT FREQUENCIES 100Hz, 1kHz, 10kHz (50Hz operation)
120Hz, 1.02kHz, 10.2kHz (60Hz operation)
Accuracy ±0.1%
MEASUREMENT LEVEL 250mV ±15mV from 100
MEASUREMENT SPEED Typically 650ms
DISPLAY 5-digit LED with decimal point plus individual LEDs for
units/multipliers
CONNECTION 4-terminal via four BNC connectors.
Optional: Kelvin clip-leads.
Optional: Component Fixture 1006.
AUTOMATIC FUNCTIONS Auto-range with manual lock. Series/Parallel equivalent circuit
with manual override. Auto component mode (R, L or C) with
manual override.
CAPACITOR POLARIZATION Internal 2V DC supply, manually selected. Inhibited on L, R
and Auto.
TRIMMING Automatic compensation.
BINNING 8 bins with rectangular limits.
8 bins with absolute limits.
Reject and minor term reject bins.
IEEE INTERFACE (GPIB) Automatic output of measurement data.
Full remote control of all functions
PARAMETER STORAGE Binning limits and trim compensation values are retained in a
non-volatile store during power off.


PROTECTION Between any pair of terminals, or any terminal and ground,
protection against damage due to connection of charged
4­4 Automatic LCR Meter 7330 · 9H7330 · Ver 2.0

capacitors is provided, subject to the following:
a) Measurement leads to be same type and minimum
length as the optional WK Kelvin clip-leads (750mm -
but can be longer).
b) Between red and ground, protection limited to 500V,
2mF. Other terminals to ground, same as protection
between terminals (see item c).
c) Graph full line shows protection; dotted line shows
approximate levels at which internal protection fuses
will blow.
d) Protection as defined above, assumes capacitor is
connected for not more than 2 seconds (as would apply
with a handler system), even if the fuses blow.




* see item c
Fig 4­1 Protection Graph
Automatic LCR Meter 7330 · 9H7330 · Ver 2.0 4­5




ACCURACY
Beyond the ranges shown, accuracy degrades linearly (see Fig 4­2 Accuracy Graphs).
RESISTANCE (Q<0.1) CAL UNCAL
100Hz/120Hz 0 - 500k ±0.1% ±1m
1kHz 0 - 1M ±0.1% ±1m ±0.5% ±5m
10kHz 0 - 1M ±0.1% ±1m ±0.5% ±5m
Resolution 0.1m
Max Display 990M
CAPACITANCE (D<0.1) CAL UNCAL
100Hz/120Hz 0 - 1600µF ±0.1% ±2pF
1kHz 0 - 160µF ±0.1% ±0.1pF ±0.5% ±0.5pF
10kHz 0 - 16µF ±0.1% ±0.01pF ±0.5% ±0.5pF
Resolution 0.001pF
Max Display 990mF
INDUCTANCE (Q>10) CAL UNCAL
100Hz/120Hz 0 - 800H ±0.1% ±1µH
1kHz 0 - 160H ±0.1% ±0.1µH ±0.5% ±0.5µH
10kHz 0 - 16H ±0.1% ±0.01µH ±0.5% ±0.5µH
Resolution 1nH
Max Display 9900H
DISSIPATION (D) CAL UNCAL
2
3.2nF - 1600µF ±0.001 (1+D )
160pF - 160µF ±0.001 (1+D2) ±0.005 (1+D2)
16pF - 1.6µF ±0.001 (1+D2) ±0.005 (1+D2)
Resolution 0.0001
Max Display 9900
Q FACTOR CAL UNCAL
1.6mH - 800H ±0.1 (Q+1/Q)%
160µH - 160H ±0.1 (Q+1/Q)% ±0.5 (Q+1/Q)%
16µH - 1.6H ±0.1 (Q+1/Q)% ±0.5 (Q+1/Q)%
Resolution 0.0001
Max Display 9900
4­6 Automatic LCR Meter 7330 · 9H7330 · Ver 2.0




Fig 4­2 Accuracy Graphs
Automatic LCR Meter 7330 · 9H7330 · Ver 2.0 5­1



5. USER INSTRUCTIONS

5.1 Ventilation
The instrument must be located so that the ventilation holes in the bottom cover and in the rear
panel are not obstructed in any manner.

5.2 Measurement Connections
Available as options are Kelvin clip-leads and Component Fixture 1006. Both items have
colour-coded connectors which must always be connected to the corresponding panel sockets
(see section 5.4). Both types provide four-terminal connections and the spring-loaded jaws of
the fixture accept axial or radial leads; spacing between the two sets of leads is adjustable to
suit most sizes of component.

5.3 Initial Settings.
At power up, the instrument always selects a test frequency of 1kHz and operates in the Auto
mode. In this condition, any type of component can be connected and its value obtained. The
instrument determines automatically whether an inductor, capacitor or resistor has been
connected, and automatically selects the correct range for accurate measurement.
When the instrument has already been used, possibly for other types of readout such as %, Q, D
or Binning, these initial settings can be re-established most quickly by momentarily switching
off. As the user gains familiarity with the instrument, however, the appropriate keyboard
operations will become apparent. The sequence covering all situations (as an alternative to
power off-on) is:
1) Press value
2) Select Abs
3) Press Auto
4) Press 1kHz
5) Press Measure/Continuous until its LED has flashed at least TWICE.
The instrument is now in the same condition as at power up.




Fig 5­1 Keypad
5­2 Automatic LCR Meter 7330 · 9H7330 · Ver 2.0

5.4 Trimming.
For most measurements, no trimming operations are necessary. The very small corrections
applied by the 7330 are held in a non-volatile store and are significant only when the highest
possible accuracy is needed at the extremes of high or low impedance. To update the stored
values, the 7330 should be set up with the test fixture or measurement leads arranged as they
will be used for a measurement.
For all trimming operations, it is essential that the leads connected are those to be used for
subsequent measurements. Also, all leads must be colour-coded so that all four BNC connectors
are always made to the same four panel sockets. From left to right, these are:
Brown I' (Voltage sense low)
Red I (Drive return)
Orange E (Drive source)
Yellow E' (Voltage sense high)
For correct four-terminal operations (trimming and measurement), I' must be connected to I at
the component measurement point; likewise, E' must be connected to E.
For Trim s/c a solid, heavy conductor should be connected between the two pairs of
measurement connections. For Trim o/c make no connection between the two pairs of
connections, but ensure that I' is connected to I, and E' is connected to E. It is not necessary to
reset both trim values. Trim s/c is applicable only to low impedances and Trim o/c to high
impedances.
Press Shift and Trim s/c or o/c as appropriate. It takes several seconds for the 7330 to complete
a sequence of measurements of the series impedance of leads (on s/c) or shunt impedance (on
o/c). Completion is indicated by the display changing from S.C. or O.C. to a numerical readout.
The trim value obtained on short-circuit is applied automatically as a correction to all
measurements made on ranges 0-3 inclusive (up to 1000). The value on open-circuit is
applied on ranges 4-6 (above 1000).
Although the degree of trim required is quite small, the memory for trim s/c has a coverage
equal to that of range 0 (see Fig 5­5) and that for trim o/c equal to range 6. This capability may
be useful for establishing an offset for specialized applications. It also means that for normal
use an operator must ensure that, when trimming, only the appropriate short or open circuit is
used. A component connected when trimming could lead to large errors in measured values.
Each trim operation results in a pair of vector values being stored. It is therefore unnecessary to
make any particular selections of R, L, C or frequency.

5.4.1 Using the Optional Kelvin Clip-Leads for Trimming
Each Kelvin-clip lead provides one pair of like sense and drive connections (e.g., I' and I - one
at each jaw). So, when the jaws are closed (or clipped to a component wire), I' is connected to I
on one clip, and E' is connected to E on the other. These connections must exist for correct
four-terminal operations - trimming and measurement.

5.5 Unknown Component Tests.
Assuming the instrument has the initial settings (see section 5.3), perform the following:
1) Connect the component between the measurement leads.
Automatic LCR Meter 7330 · 9H7330 · Ver 2.0 5­3


2) Read the value from the display, in association with the units indicated by an LED:
, k or M for resistors
µH, mH or H for inductors
pF, nF, µF or mF for capacitors
3) Another LED will show Series (impedances below 1000) or Parallel (above 1000).
Further information on this is described in section 6.2.
4) If the component is an inductor and the Q factor is required, refer to section 5.8.1.
5) If the component is a capacitor and the dissipation factor (D) is required, refer to section
5.9. Information on polarizing capacitors is described in section 5.9.3.
6) Remove the component and substitute the next unknown component.

5.6 Test Frequency Selection.
The Initial Settings, as produced at switch-on, include the selection of 1kHz as the test
frequency. However, users may at any time choose any one of the three test frequencies
available.
50Hz operation: 100Hz 1kHz 10kHz
60Hz operation: 120Hz 1.02kHz 10.2kHz
An LED shows which frequency is in use.

Note:
· A change of frequency will often result in the measured impedance crossing the 1000
change-over point between Series and Parallel readout. Further information on this is
described in section 6.2.
· Text references to 100Hz, 1kHz and 10kHz, for 50Hz operation, apply to 60Hz operation as
120Hz, 1.02kHz and 10.2kHz, respectively.

5.7 Resistance Measurement.
Assuming the instrument has the Initial Settings (see section 5.3), perform the following:
1) Select R and connect the resistor between the measurement leads.
2) Read the value from the display, in association with the units indicated by an LED (, k,
or M).
3) Remove the resistor and substitute the next one to be measured.

Note:
· It is not unusual for small changes to occur in the measured value of a resistor when the test
frequency is changed. The effect is caused by small reactive terms which are present with
all resistors. Their effect is minimal when tests are made at 100/120Hz.
· The high resolution of the instrument may also show up variations in resistance due to
temperature changes.
5­4 Automatic LCR Meter 7330 · 9H7330 · Ver 2.0

5.8 Inductance Measurement.
Assuming the Instrument has the Initial Settings (see section 5.3), perform the following:
1) Select L and connect the inductor between the measurement leads.
2) Read the value from the display, in association with the units indicated by an LED (µH,
mH or H).
3) Remove the inductor and substitute the next one to be measured.

5.8.1 Measurement of Q Factor & Loss Resistance
With the inductor connected as described above, press L followed by the Q/D key. (The L key
must have been used: Q is not available when reading inductance in the Auto mode.) The
display gives the Q factor. To return to inductance measurement, re-press either Q or L.
If required, the loss resistance of the inductor can be measured by selecting R, or it can be
calculated from the expressions:

L
Series: R=
Q
Parallel: R =L Q
where = 2 × frequency

Note:
Because both the inductance and the effective loss resistance of iron-cored coils vary with the
frequency and level of the test signal, and with any dc passed, the measured Q value will be
subject to variations, and these can be substantial.

5.8.2 Measuring Small Value Inductors
Small-value inductors are usually best measured at 10kHz. For the best accuracy when
measuring small-value inductors, it is necessary to ensure that the values stored for the Trim s/c
automatic correction are appropriate for the configuration in use (see section 5.4).
It must be appreciated that when an inductor is measured at a frequency much lower than that
for which it is designed (e.g., an hf choke tested at af) it will tend to behave as an inductive
resistor. Also, in the Auto mode, the value displayed will be resistance. In these circumstances,
the inductance measurement accuracy is widened by the factor (1 + 1/Q). The value of this
factor can be determined by using the Q facility. Air-cored coils are particularly susceptible to
noise pick-up. For this reason, keep them well clear of power transformers and, whenever
possible, measure at 10kHz. Tests at 100Hz may be marred by noise.

5.8.3 Measuring Iron-Cored Inductors
Ferrite-cored coils are usually best measured at 1kHz. Larger audio inductors, with laminated
cores, are normally checked at 100Hz. When core materials can be damaged by excessive
magnetization (for example, some tape heads and microphone transformers), check before
connection that the test signal level (250mV via 100) is acceptable. It should also be noted
that a residual 20mV dc is present at the measurement connections. If this is unacceptable, use a
series blocking capacitor of not less than 100µF (C1 in Fig 5­2).
Automatic LCR Meter 7330 · 9H7330 · Ver 2.0 5­5


The effective value of all iron-cored inductors can vary widely with the magnetization and,
therefore, with the level of the test signal. Ideally, they should be measured at the frequency of
use, with the same ac and dc levels as apply in use. However, valuable results, especially
comparative values, can usually be obtained by passing a direct current through the inductor
while under test.
The essential requirements are to prevent this current entering the instrument measurement
circuits, and to minimize the effect of the dc supply components on the measured value. The
circuit arrangement for energizing inductors, as shown in Fig 5­2 achieves this.




Fig 5­2 Circuit Arrangement for Energizing Inductors



WARNING!
Absolute maximum voltage of the supply is 100V. Care must be taken to ensure correct
polarity.
FAILURE TO OBSERVE THIS WILL RESULT IN PERMANENT DAMAGE TO THE
INSTRUMENT, NOT COVERED BY THE WARRANTY, AND MAY PUT THE USER
AT RISK.


Lu is the inductor under test.
C1 should be 100µF and of a working voltage to suit the voltage of the dc supply.
The direct current through the inductor is also passed by resistors R1 and R2, which must have
an adequate power rating. However, measurement errors will arise if the resistance values are
made too low.
For 1% accuracy, the minimum values for C and R1 are:


C: 1000µF R1:500


The minimum value of R2 can be found by first calculating Zu:
5­6 Automatic LCR Meter 7330 · 9H7330 · Ver 2.0


Zu = [Ru 2
+ ( 2 f Lu )
2
]
where Ru = resistance of unknown (Series, ohms)
f = test frequency
Lu = inductance of unknown (Series)
and, from this value of Zu, using the graph (Fig 5­3) to read R2.




Fig 5­3 Minimum Shunt Load Impedance for 1% Loss of Accuracy



The shunting effect of R1 and R2 in a given measurement an easily be assessed by substituting
a short-circuit for the dc supply, and then noting the change in measured value when R1 and R2
are disconnected.

5.9 CAPACITANCE MEASUREMENT.
Assuming the instrument has the Initial Settings (see section 5.3), perform the following:
1) Select C and connect the capacitor between the measurement leads.
2) Read the value from the display, in association with the units indicated by an LED (pF, nF,
µF or mF).
3) Remove the capacitor and substitute the next one to be measured.

5.9.1 Measurement of D Factor & Loss Resistance
With the capacitor in position as described above, press C followed by the Q/D key. (The C key
must have been used. D is not available when reading capacitance in the Auto mode.) The
display gives the dissipation factor. To return to capacitance measurement, re-press either D or
C.
If required, the loss resistance of the capacitor can be measured by selecting R, or it can be
calculated from the expressions:
Automatic LCR Meter 7330 · 9H7330 · Ver 2.0 5­7


D
Series: R=
C
1
Parallel: R=
CD
where = 2 × frequency

5.9.2 Measuring Small Value Capacitors
For the best accuracy when measuring small-value capacitors, it is necessary to ensure that the
values stored for the Trim o/c automatic correction are appropriate for the configuration in use.
Position the leads and measurement clips or fixture exactly as they will be used for the
measurement but with no component connected. (Ensuring that I' is linked to I and, separately,
E' is linked to E (see section 5.4). Press Shift and Trim o/c. The 7330 will reset the stored
correction figure for stray impedance and this will be deducted automatically from all
subsequent measurements.

5.9.3 Measuring Electrolytic Capacitors
With a capacitor in position and with C selected (NOT Auto), pressing the Bias key will apply
2V positive bias from an internal supply to the E (Orange) connecting lead. An LED is
illuminated on the Bias key while the 2V is applied. A second press of the key removes the
bias. If bias exceeding 2V is required, use the circuit shown in Fig 5­4. Cu is the capacitor
under test. C1 should be >100 µF and of a working voltage to suit the voltage of the dc supply.




Fig 5­4 Bias Circuit for Capacitors



WARNING!
Absolute maximum voltage of the supply is 100V. Care must be taken to ensure correct
polarity.
FAILURE TO OBSERVE THIS WILL RESULT IN PERMANENT DAMAGE TO THE
INSTRUMENT, NOT COVERED BY THE WARRANTY, AND MAY PUT THE USER
AT RISK.
5­8 Automatic LCR Meter 7330 · 9H7330 · Ver 2.0

R should be 330 and of adequate power rating to take account of short-circuit capacitors
(i.e., 100V, 330, 30W).

5.9.4 Charged Capacitor Protection
Refer to the protection text and graph given in section 4.2 `Specifications - PERFORMANCE -
PROTECTION'.

5.9.5 Semiconductor Junction Capacitance
Because of the small value of the test voltage and the availability of 2V bias, the 7330 provides
quick and reliable readout of semiconductor junction capacitance.
1) Select C, Bias, and the required frequency.
2) Connect the semiconductor so that it is reverse-biased (i.e., cathode to the I (red)
connecting lead).
3) Note the value and substitute the next component to be checked, again taking care to
obtain reverse bias.

5.10 Deviation Readout.
As an alternative to reading resistance, inductance or capacitance as an absolute value, the 7330
can provide direct readout of these three properties in terms of % deviation from a specified
nominal value. The procedure for setting a nominal value and subsequent tests, is as follows:
1) Press: Value
Select: % (on the %/Abs white key)
Press: Shift
Press: Nom
The existing stored value will be displayed.
2) Key in up to five digits and (if needed) a decimal point for the required nominal value.
3) Press: Shift
Press: Units required (, µH, pF, etc.)
Wait until the nominal value is displayed.
4) Press: Value
5) Connect each component in turn to obtain a reading of % deviation from the nominal
value entered. Maximum reading is ±99.9%. Components whose value deviates by more
than this (or components of the wrong type) will produce a display of o.d.r. (outside
display range).
Most of the facilities for Absolute measurements are available also in the % mode. Note that
the 7330 cannot provide % deviation readout on Q and D values. The nominal value for %
deviation readout is the same as that used for binning.

5.11 Continuous/Single-Shot Measurements.
In normal use, the 7330 makes a new measurement, and updates the display, at intervals of
approximately 650ms. This provides a convenient readout of changing values and where values
fluctuate very widely, indicates that the measured component is unstable or that the term
Automatic LCR Meter 7330 · 9H7330 · Ver 2.0 5­9


requested either lies outside the coverage of the instrument or is virtually swamped by another
term.
For some applications, it may be more convenient to have a one-off measurement, the result
being shown on the display for as long as required. To obtain this condition, momentarily press
Measure/Continuous. A measured value will then be stored and removal of the component
under test, or substitution of another one, will not affect the readout. When another single-shot
measurement is required, again momentarily press Measure/Continuous. To return to normal
(Continuous) mode, press the key for at least two flashes of the LED. The mode in use is shown
by this LED:
Flashing: Continuous
Off: Single-shot

5.12 Range Selection
Normally the 7330 automatically selects the correct range for accurate measurement. This
occurs in the Value or Sort mode, for single-shot or repetitive measurement. The Hold key can
be used to lock the instrument on to the range it has selected in this way (described in section
5.13). However, it is also possible to pre-select a particular range. The key sequence to achieve
this is:
1) Shift
2) Range no
3) Any key 0-6, according to the range required.
Coverage of the seven ranges is shown in Fig 5­5. It should be borne in mind that pre-selection
of a particular range to examine one term of a complex impedance may cause an overload by
the major term. Also, changing frequency may necessitate a change of range.
5­10 Automatic LCR Meter 7330 · 9H7330 · Ver 2.0




Fig 5­5 Impedance Chart
Automatic LCR Meter 7330 · 9H7330 · Ver 2.0 5­11


5.13 Hold Facility
When a number of similar components are to be checked, the short time taken by the instrument
for the autoranging function can be eliminated. With a component connected, and its value
displayed, press Hold. The range in use (selected by the instrument) will not be held for all
subsequent tests (value or Sort). The Hold function is indicated by the LED illuminating by the
Hold key. To turn to autoranging, re-press Hold.

5.14 Display Characteristics

5.14.1 General
All values displayed by the 7330 are derived by internal computation. Some of these
computations may involve denominators whose value approaches zero, giving rise to large,
unstable results. If a value is too large to be displayed (i.e., exceeding 99M, 99mF or 9900H),
the over-range indication will appear:
o.r.
If Hold has been selected, and a component connected subsequently causes an overload, the
display will be:
Hold.r.
The impedance may lie outside the range capability because it is an extreme value, because the
frequency is selected is unsuitable, or because the range Hold has been used inappropriately.

5.14.2 Negative Reactance
If C is selected with an inductor connected, or L with a capacitor connected, the 7330 will,
within the capability of the display, show a negative value in the terms selected. This will be
the value of capacitance (or inductance) whose reactance at the test frequency is equal to that of
the component connected. It is, of course, the value to produce resonance