BK Precision BK Precision 886 Manual

Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 - TestEquipmentDepot.com

Models

885 & 886
LCR METER
OPERATING

MANUAL

MANUAL DE INSTRUCCIÓNES

MEDIDOR LCR

Modelos 885 & 886

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Contents

1. INTRODUCTION ...............................................................

1.1 G

ENERAL

............................................................................. 1

MPEDANCE PARAMETERS

1.2 I

PECIFICATION

1.3 S

CCESSORIES

1.4 A

.................................................................... 6

.................................................................... 19

.................................................. 3

2. OPERATION ...................................................................... 21

2.1 P

HYSICAL DESCRIPTION

AKING MEASUREMENT

2.2 M

2.2.1 Battery Re placement ............................................................... 22

2.2.2 Battery Recharging/AC operation .......................................... 23

2.2.3 Open and Short Calibration ................................................... 24

2.2.4 Display Sp eed .......................................................................... 25

2.2.5 Relative Mode ......................................................................... 25

2.2.6 Range Hold.............................................................................. 25

2.2.7 DC Resistance Measurement .................................................. 26

2.2.8 AC Impedance Measurement .................................................. 26

2.2.9 Capacitance Measurement ..................................................... 26

2.2.10 Inductance Measurement ........................................................ 27

2.3 A

CCESSORY OPERATION

................................................... 21

................................................. 21

................................................... 28

4. APPLICATION .................................................................. 30

4.1 T

EST LEADS CONNECTION

PEN/SHORT COMPENSATION

4.2 O

ELECTING THE SERIES OR PARALLEL MODE

4.3 S

............................................... 30

.......................................... 35

.................. 37

5. LIMITED ONE-YEAR WARRANTY ........................... 37

6. SAFETY PRECAUTION ................................................. 42

1

1. Introduction

1.1 General

The B&K Precision Models 885 & 886 Synthesized In-Circuit
LCR/ESR Meter is a high accuracy hand held portable test
instrument used for measuring inductors, capacitors and resistors
with a basic accuracy of 0.2%. It is the most adva nced handheld
AC/DC impedance measurement instrument to date. The 885 or 886
can help engineers and student s to understand the character istic of
electronics components as well as being an essential tool on any
service bench.

The instrument is auto or manual ranging. Test frequencies of
100Hz, 120Hz, 1KHz 10KHz or 100KHz (886) may be selecte d on
all applicable ranges. The test voltages of 50mVrms, 0.25Vrms,
1Vr ms or 1VDC (DCR only) may also be selected on all applicable
ranges. The dual display feature permits simultaneous
measurements.

Components can be measured in the series or parallel mode as
desired; the more standard method is automatically selected first but
can be overridden.

The Model 885 and 886 offers three useful modes for sorting
components.

The highly versatile Mode ls can perf orm virtua lly all the functions
of most bench type LCR bri dges. With a basic accuracy of 0.2%,
this economical LCR meter may be adequately substituted for a

1

more expensive LCR bridge in many situations. The meter is
powered from two AA Batteries and is supplie d with an AC to DC
charging adapter and two AA Ni-Mh Rechargeable Batteries.

The instrument has applications in electronic engineering labs,
production facilitie s, service shops, and schools. It can be used to
check ESR v alues of capacito rs , sort values, select precision values,
measure unmarked and unknown i nductors, capacit ors or resistor s,
and to measure capacitance, inductance, or resistance of cables,
switches, circuit boar d foils, etc.

The key features are as following:



Te st condition:

Frequency : 100Hz / 120Hz / 1KHz / 10KHz /

1

100KHz (886)

Level : 1Vrms / 0.25Vr ms / 50mVrms /

2.
1VDC (DCR only)



Measurement Parameters : Z, Ls, Lp , C s, C p , D C R ,



Basic Accu racy: 0.2%



Dual Liquid Crystal Display



Fast/Slow Measurement



Auto Range or Range Hold



Open/Short Calibrati on



Primary Parameters Display:

ESR, D, Q and

θ

Z : AC Impedance
DCR : DC Resistance
Ls : Serial Inductance
Lp : Parallel Inductance

2

Cs : Serial Capacitance
Cp : Parallel Capacitance



Second Parameter Display:

θ

: Phase Angle

ESR : Equivalence Serial Resistance
D : Dissipati on Fact or
Q : Quality Factor



Combinations of Display:

Serial Mode : Z –

θ

, Cs – D, Cs – Q, Cs – ESR, Ls –

D, Ls – Q, Ls – ESR

Parallel M od e : Cp – D, Cp – Q, Lp – D, Lp – Q

1.2 Impedanc e Parameters

Due to the different test ing signal s on t he impedance mea surement
instrument, there are DC impedance and AC impedance. The
common digital multi -meter can only measure the DC impedance,
but the Model 885 can do both. It is a very important issue to
understand the impedance parameters of the electronic component.

When we analysis the impedance by the impedance measurement
plane (Figure 1.1). It can be visualized by the rea l element on the
X-axis and the imaginary element on the y-axis. This impedance
measuremen t plan e can also be seen as th e pola r coordin at es. Th e Z

θ

is the magnitude and the

is the phase of the impedance.

3

( )

( )

( )

( )
( )

Ohm

Reactance

Resistance

Impedance

1

22

=Ω

=

=

=















==

+==

Ω∠=+=

−

S

S

s

s

s

sss

ss

X

R

Z

R

X

TanSinZX

XRZCosZR

ZjXRZ

θθ

θ

θ

s

X

s

R

( )

sX,RZ

s

Z

θ

Imaginary Axis

Real Axis

Figure 1.1

fCC

X

fLLX

C

L

πω

πω

2

11

2====

There are two different types of reactance: Inductive (X
Capacitive (X

). It can be defined as f ollows:

C

L = Inductance (H)

Also, there are quality factor (Q) and the dissipation fac tor (D) that
need to be discussed. For component, the quality fa ctor serve s as a
measure of the reacta nce purity. In the re al world, t here is always

C = Capacitance (F)
f = Frequency (Hz)

4

) and

L

pp

p

p

p

p

sss

s

s

s

RC

L

R

X

R

G

B

RCR

L

R

X

D

Q

ω

ω

ω

ω

δ

===

=

===

==

1

tan

11

some associated resistance that dissipates power, decreasing the
amount of energy that can be rec overed. The quality fac tor can be
defined as the ratio of the stored energy (reactance) and the
dissipated energy (resistance). Q is generally used for inductors and
D for capacito rs .

There are two types of the circuit mode. One is series mode, the
other is parallel mode. See Fi gure 1.2 t o find out t he rela tion of t he
series and parallel mode.

5

Parameter

Range

Z
L

0.000 µH to 9999 H

C

0.000 pF to 9999 F

DCR

ESR

D

0.000 to 9999

Q

0.000 to 9999

ss

jXRZ +=

Real and imaginary components are Parallel

jB=1/jX

jBGY +=

jX

R

P

jX

1

P

R

1

Y +=

Real and imaginary components are serial

Rs jX

s

p

p

Figure 1.2

G=1/R

1.3 Specification



LCD Display Range:

0.000 Ω to 9999 MΩ

0.000 Ω to 9999 MΩ

0.000 Ω to 9999 Ω

6

p

p

|Zx|

20M ~

(Ω)

10M ~

(Ω)

1M ~

(Ω)

100K ~

(Ω)

10 ~ 1

(Ω)

1 ~ 0.1

(Ω)

DCR

100Hz

120Hz

1KHz

10KHz

100KHz

NA

2

1 Dx+

θ

-180.0 ° to 180.0 °



Accuracy (Ae):

Z Accuracy:

10M

1M

100K

10

Freq.

2% ±1



5% ±1

±

1 0.5% ±1 0.2% ±1 0.5% ±1 1% ±1

1%

2% ±1



(886)

5%±1

2%±1 0.4% ±1 2%±1 5%±1



Note : 1.The accuracy applies wh en th e test level is set to 1V rms.

2.Ae multiplies 1. 25 when the test level is set to 250mVrms.

3.Ae multiplies 1.50 when the test level is set to 50mVrms.

4.When measuring L and C, multiply Ae by
Dx

＞

0.1.



: Ae is not specified if th e test level is set to 50mV.

7





if the

79.57

pF

159.1

nF

1.591

nF

15.91

uF

159.1

uF

1591

mF

2% ± 1



1% ± 1

0.5%
± 1

0.2%
± 1

0.5%
± 1

1% ± 1



66.31

pF

132.6

nF

1.326

nF

13.26

uF

132.6

uF

1326

mF

2% ± 1

1% ± 1

0.5%

1

0.2%

1

0.5%

1

1% ± 1

7.957

pF

15.91

pF

159.1

nF

1.591

uF

15.91

uF

159.1

mF

2% ± 1



1% ± 1

0.5%
± 1

0.2%
± 1

0.5%
± 1

1% ± 1



0.795

pF

1.591

pF

15.91

pF

159.1

uF

1.591

uF

15.91

uF

5% ± 1



2% ± 1

0.5%
± 1

0.2%
± 1

0.5%
± 1

1% ± 1



NA

0.159

pF

1.591

pF

15.91

nF

159.1

uF

1.591

uF

C Accuracy :

100Hz

120Hz

159.1

132.6

pF

|

pF

|

pF

|

1.591

pF

|

1.326

nF

|

15.91

nF

|

13.26

nF

|

159.1

nF

|

132.6

uF

|

1591

uF

|

1326

uF

|

15.91

uF

|

13.26

1KHz

10KHz

100KHz

(886)



pF

|

15.91

pF

|

1.591

pF

|

159.1

pF

|

15.91

pF

|

1.591

±

pF

|

1.591

pF

|

159.1

pF

|

15.91

8

±

nF

|

15.91

pF

|

1.591

pF

|

159.1

±

uF

|

159.1

uF

|

15.91

nF

|

1.591



uF

|

1.591

uF

|

159.1

uF

|

15.91

NA

5% ± 1

2%± 1

0.4%

1

2%± 1

5% ± 1

31.83

KH

15.91

H

1591

H

159.1

mH

15.91

mH

1.591

uH

2% ± 1



1% ± 1

0.5%
± 1

0.2%
± 1

0.5%
± 1

1% ± 1



26.52

KH

13.26

H

1326

H

132.6

mH

13.26

mH

1.326

uH

2% ± 1



1% ± 1

0.5%
± 1

0.2%
± 1

0.5%
± 1

1% ± 1



31.83

KH

1.591

H

159.1

H

15.91

mH

1.591

uH

159.1

uH

2% ± 1

1% ± 1

0.5%

1

0.2%

1

0.5%

1

1% ± 1

318.3

H

159.1

H

15.91

H

1.591

uH

159.1

uH

15.91

uH

5% ± 1

2% ± 1

0.5%

0.2%

0.5%

1% ± 1

31.83

H

15.91

H

1.591

mH

159.1

uH

15.91

uH

1.591

uH

L Accuracy :

KH

100Hz

120Hz

1KHz

10KHz

15.91

KH

13.26

KH

1.591

159.1



H





KH

|

|

1591

159.1

KH

|

|

1326

132.6

KH

|

|

159.1

15.91

H

|

|

15.91

1.591

H

|

H

|

H

|

±

H

|

± 1

±

H

|

H

|

H

|

±

H

|

± 1

mH

1.591

mH

1.326

mH

159.1

±

uH

15.91

± 1

15.91

13.26

1.591

159.1



mH

|

|

159.1

mH

|

|

132.6

uH

|

|

15.91



uH

|

|

1.591



100KHz

(886)

H

|

15.91

H

|

1.591

H

|

159.1

9

mH

|

15.91

uH

|

1.591

uH

|

0.159

NA

5% ± 1

2%± 1

0.4%

1

2%± 1

5% ± 1

|Zx|

Freq.

20M ~

(Ω)

10M ~

(Ω)

1M ~

(Ω)

100K ~

(Ω)

10 ~ 1

(Ω)

1 ~ 0.1

(Ω)

±

0.020

±

0.010

±

0.005 ±0.002 ±0.005 ±0.010

±

0.050

±

0.020

100KHz

(886)

NA ±0.050

±

0.020 ±0.004 ±0.020 ±0.050

|Zx|

Freq.

20M ~

(Ω)

10M ~

(Ω)

1M ~

(Ω)

100K ~

(Ω)

10 ~ 1

(Ω)

1 ~ 0.1

(Ω)

±

1.046

±

0.523

±

0.261 ±0.105 ±0.261 ±0.523

±

2.615

±

1.046

100KHz

(886)

NA ±2.615

±

1.046 ±0.209 ±1.046 ±2.615

D Accuracy :

100Hz
120Hz

1KHz

10KHz

θ Accuracy :

100Hz
120Hz

1KHz

10KHz

10M





10M







1M

100K



1M

100K



10

±

10

10











CxfZx⋅⋅⋅

=

π

2

1

2

1 Dx+

Ω=

⋅⋅⋅⋅

=

⋅⋅⋅

=

−

1590

10100102

1

2

1

93

π

π

Cxf

Zx

Z Accuracy:

As shown in table 1.

C Accuracy:

= Ae of |Zx|

C

Ae

f : Test Frequency (Hz)
Cx : Measured Capacitance Value (F)

|Zx| : Measured Impedance Value (
Accuracy applies when Dx (measured D value)

Ω

)

≦

0.1

When Dx > 0.1, multiply C

Example:
Test Condition:
Frequency : 1KHz
Level : 1Vrms
Speed : Slow
DUT : 100nF
Then

Ae

by

11

LxfZx ⋅⋅⋅=π2

2

1 Dx+

100

Ae

XxESR

Ae

⋅±=

Refer to the accuracy table, get C

L Accuracy:

= Ae of |Zx|

L

Ae

f : Test Frequency (Hz)
Lx : Measured Inductance Value (H)

|Zx| : Measured Impedance Value (
Accuracy applies when Dx (measured D value)

=±0.2%

Ae

Ω

)

≦

0.1

ESR Accuracy :

When Dx > 0.1, multiply L

Ae

by

Example:
Test Condition:
Frequency : 1KHz
Level : 1Vrms
Speed : Slow
DUT : 1mH
Then

2

π

⋅⋅⋅=

π

LxfZx

−

33

283.610102

Refer to the accuracy table, get L

12

Ω=⋅⋅⋅=

Ae

=±0.5%

Cxf

LxfXx

⋅⋅⋅

=⋅⋅⋅=

π

π

2

1

2

Ω=

⋅⋅⋅⋅

=

⋅⋅⋅

=

−

1590

10100102

1

2

1

93

π

π

Cxf

Zx

Ω±=⋅±= 18.3

100

Ae

Xx

ESR

Ae

ESR

= Ae of |Zx|

Ae

f : Test Frequency (Hz)
Xx : Measured Reactance Value (

Lx : Measured Inductance Value (H)
Cx : Measured Capacitance Value (F)

Accuracy applies when Dx (measured D value)

Example:
Test Condition:
Frequency : 1KHz
Level : 1Vrms
Speed : Slow
DUT : 100nF
Then

Refer to the accuracy table, get

=±0.2%,

C

Ae

Ω

)

≦

0.1

D Accuracy:

13

100

Ae

D

Ae

±=

Ω=

⋅⋅⋅⋅

=

⋅⋅⋅

=

−

1590

10100102

1

2

1

93

π

π

Cxf

Zx

002.0

100

±=⋅±=

Ae

D

Ae

DeQx

DeQx

Ae

Q

⋅

⋅

±=

1

2

= Ae of |Zx|

D

Ae

Accuracy applies when Dx (measured D value)
When Dx > 0.1, multiply Dx by (1+Dx)

Example:
Test Condition:
Frequency : 1KHz
Level : 1Vrms
Speed : Slow
DUT : 100nF
Then

Refer to the accuracy table, get

=±0.2%,

C

Ae

≦

0.1

Q Accuracy:

14

005.0

100

±=⋅±=

Ae

De

1.01

= Ae of |Zx|

Q

Ae

Qx : Measured Quality Factor Value
De : Relative D Accuracy
Accuracy applies when

Example:
Test Condition:
Frequency : 1KHz
Level : 1Vrms
Speed : Slow
DUT : 1mH
Then

2

π

⋅⋅⋅=

π

LxfZx

−

33

Refer to the accuracy table, get

=±0.5%,

L

Ae

If measured Qx = 20
Then

2

⋅

1

±=⋅

DeQx

DeQx

±=

Q

Ae

2



1<⋅ DeQx

Ω=⋅⋅⋅=

283.610102

15

100

Ae

π

180

e ⋅=θ

Ω=

⋅⋅⋅⋅

=

⋅⋅⋅

=

−

1590

10100102

1

2

1

93

π

π

Cxf

Zx

deg115.0

100

2.0180

100

Ae180

Ae

±=⋅

π

±=

⋅

π

±=θ

θ

Accuracy:

Example:
Test Condition:
Frequency : 1KHz
Level : 1Vrms
Speed : Slow
DUT : 100nF
Then

Refer to the accuracy table, get

=±0.2%,

Z

Ae



Testi ng Signal:
Level Accuracy : ± 5%
Frequency Accuracy : 0.1%

16



Output Impedance : 100Ω ± 5%



Measuring Speed:
Fast : 4.5 meas. / sec.
Slow : 2.5 meas. / sec.



General:
Temperature : 0

°

C to 70°C (Operating)

-20
Relative Humidity : Up to 85%

Battery Type : 2 AA si ze Ni-Mh or Alkaline
Battery Charge : Const ant current 150mA

Battery Operatin g Time : 2.5 Hours typical
AC Operation : 110/220V AC, 60/50Hz with proper

Low Power Warning : under 2.2V
Dimensions : 174mm x 86mm x 48mm (L x W x H)

Weight : 470g

Considerations

Test Fre quency. The test frequency is user selectable and can be
changed. G ene rally, a 1 KHz test signal or higher is used to measure
capacitors that are 0.01uF or smaller and a 120Hz test signal is used
for capacitors that are 10uF or larger. T ypically a 1 kHz test signal or
higher is used to measure induc tors that are used in audio and RF
(radio frequency) circuits. This is because these components operate
at higher frequencies and require that they be measure d at a hi gher
frequency of 1 KHz. Generally, inductors below 2mH should be

°

C to 70°C (Storage)

approximately

adapter

6.9” x 3.4” x 1.9”

17

measured at 1 kHz and inductors above 200H should be measured at
120Hz.

It is best to check with the componen t manufacturers’ data sheet to
determine the best test fre quency for the device.

Charged Capacitors
Always discharge any capacitor prior to making a
measurement since a charged ca pacitor may serious ly damage
the meter.

Effect Of High D on Accuracy
A low D (Dissipation Factor) reading is desirable. Electrolytic
capacitor s inhe rently have a higher dissipation factor due to their
normally high internal leakage characteristics. If the D (Dissipation
Factor) is ex c es sive, the capacitanc e measurement accuracy may be
degraded.

It is best to check with the componen t manufacturers’ data sheet to
determine the desirabl e D val ue of a good component.

Measuring Capacitance of Cables, Switches or Other Parts
Measuring the capacitance of coaxial cables is very useful in
determining the actual length of the cable. Most manufacturer
specifications list the amount of capacitance per foot of cable and
therefore the length of the cable can be determined by measuring the
capacitance of that cable.

For examp le: A manufa cturers , specificat ion calls out a certa in cable,

18

to have a capa citance of 10 pF per foot, After measuring the cable a
capacitance reading of 1.000 nF is displayed. Dividing 1000pF
(1.000 nF) by 10 pF per foot yields the length of the cable to be
approximately 100 feet.

Even if the manufacturers’ specification is not known, the
capacitance of a measured length of cable (such as 10 feet) can be
used to determine the capacitance per foot; do not use too short a
length such as one foot, because any error becomes magnified in the
total leng th calculations.

Sometimes , the cap aci tan ce of switches, int er co n n ect cables, circuit
board foils, or other parts, affecting stray capacitance can be critical
to circuit design, or must be repeatable from one unit t o anot her.

Series Vs P a ra llel Measurement (for Indu ctors)
The seri es mode dis plays the more accurate me asurement in most
cases. The series equivalent mode is essential for obtaining an
accurate Q reading of l ow Q inductors. Where ohmic losses are
most significant, the series equivalent mode is preferr ed. However,
there are cases where the parallel equivalent mode may be more
appropriate. For iron core induct or s operating at higher fre quenci es
where hysteresis and eddy currents become significant,
measurement in the parallel equivalent mode is preferred.

1.4 Accessories



Operating Manual 1 pc



2 AA Size Ni-Mh Rechargeable Batteries 2 pc

19



Shorting Bar 1 pc



AC to DC Adapter 1 pc



TL885A SMD Test Probe 1 pc



TL885B 4-Wire Test Clip (Optional)



TL08C Kelvin Clip (Optiona l)



Carrying Case (Optional)

20



1. NA

2. Primary Parameter Display

5. Model Number

6. Power Switch

7. Relative Key

8. Measurement Level Key

9. Open/Short Calibration Key

10. Measurement Frequency Key

13. Range Hold Key

14. L/C/Z/DCR Fu nction Key

15. Battery Cha rge I ndicator

16. DC Adapter Input Jack

17. Guard Term inal

18. HPOT/HCUR Terminal

2. Operation

2.1 Physical Description

G

H

POT

CUR

UARD

L

POT

LH

CUR

G

UARD

3. Secondary Parameter Display 4. Low Battery Indicator

11. D i splay Update Speed Key

12. D/Q/

21

θ

/ESR Function Key

1

Screws

Battery Compartment
Hatch

3

Batteries

4

Norm/Ni-Mh Switch

5

Back Case

6

Tilt Stand

19. LPOT/LCUR Terminal 20. Battery Compartment

2.2 Making Measurement

2.2.1 Battery Replacement
When the LOW BATTERY INDICATOR lights up duri ng normal

operation, the batteries in the Models 885 & 886 should be replaced
or recharged to maintain proper operation. Please perform the
following steps to change the batteries:

1. Remove the battery hatch by unscrewing the screw of the
battery compartment.

2. Take out the old batteries and insert the new batteries int o the

battery compartment. Please watch out for battery polarity
when installing new batteries.

3. Replace the battery hatch by rever sing the procedure used to

remove it.

2

22

23

!

rechargeable batteries.

Battery Replacement

2.2.2 Battery Recharging/AC operation

Caution

Only the Models 885 or 886 st andar d acces sory AC t o DC
adapter can be used with Model 885. Other battery elimina tor
or charger may result in damage to Modes 885 or 886.

The Models 885 & 886 works on external AC power or internal
batteries. To power the Mode l 885 wi th A C source, make s ure t hat
the Models 885 or 886 is off, then plug one end of the AC to DC
adapter into the DC jack on the right si de of the instr ument and the
other end into an AC outlet.

There is a small slide switch inside the battery compartment
called Battery Select Switch. If the Ni-Mh or Ni -Cd rechargeable
batteries are installed in Models 885 or 886, set the Batter y Select
Switch to "Ni -Mh" posi tion. The Ni-Mh or Ni-Cd batterie s can be
recharged when the instrument i s oper at ed by AC source. The LED
for indicating battery charging will light on. If the non-rechargeable
batteries (such as alkaline bat teries) are i nstalled in Models 885 or
886, set the Battery Select Switch to "NORM" position for
disconnecting the charging circuit to the batteri es.

Warning

The Battery Select Switch must be set in the "NORM"
position when using non­Non-rechargeable batt erie s may e xplode if the AC a dapter is
used with non-rechargea ble batteries. Warranty is voided if
this happened.

24

2.2.3 Open and Short Calibrati on
The Models 885 & 886 provides open/short calibration

capability so the user can get better accuracy in measuring high and
low impedance. We recommend that the user performs open/shor t
calibratio n if the test level o r frequency has been changed.



Open Calibration
First, remain ing the m easurem ent terminals with the open status,
then press the CAL key shor tly ( no mor e t han two s econd) , t he
LCD will display:

This calibration ta kes about 10 se con ds. After it is finished, the
Model 885 will beep to show that the calibration is done.



Short Calibration
To pe rform the short calibration, insert the Shorting Bar into the
measurement terminals. Press the CAL key for more t han two
second, the LCD will display:

This calibration ta kes about 10 se con ds . After it i s fi nishe d, t he
Model 885 will beep to show that the calibration is done.

25

2.2.4 Display Speed

The Models 885 & 886 provides two different display speeds
(Fast/Slow). It is controlled by the Speed key. When the speed is set
to fast, the display will update 4.5 readings every second. When the
speed is set to slow, it’s only 2.5 readings per second.

2.2.5 Relative Mod e

The relative mode lets t he user to make quick sort of a bunch of
components. First, insert the standard value compone nt to get the
standard value reading. (A pproximate ly 5 seconds in Fast Mode to
get a stable reading.) Then, press the Relative key, the primary
display will reset to zero. Remove the standard value component
and insert the unknown component, the LCD will show the value
that is the difference between the standard value and unknown
value.

2.2.6 Range Hold

To set the range hold, insert a standard component in that
measurement range. (A pproximately 5 seconds in Fast Mode to get
a stable reading.) Then, by pressing the Range Hold key it will hold
the range within 0.5 to 2 times of the current measurement range.
When the Range Hold is press the LCD di splay:

26

2.2.7 DC Resistance Measurement

The DC resistance measurement measures the resistance of an
unknown component by 1VDC. Select the L/C/Z/DCR key to make
the DCR measurement. The LCD display:

2.2.8

AC Impedan ce Mea s u r em ent

The AC impedance measurement measures the Z of an unknown
device. Sele ct th e L/C/Z/DCR key to mak e th e Z m easu rem ent. Th e
LCD display:

The testing level and fre quency can by selected by pressing t he

Level key and Frequency key, respectively.

2.2.9 Capacitance Measurement

To measure the capacitan ce o f a com ponent, select the L/C/Z/DCR
key to Cs or Cp mode. Due to the circuit structure, t here are two
modes can by selected (Serial Mode – Cs and Para llel Mode – Cp).
If the serial mode (Cs) is selected, the D, Q and ESR can be shown
on the secondary display. If the parallel mode (Cp) is selected, only
the D and Q can be shown on the secondary display. The following

27

shows some examples of capacitance measurement:

The testing level and fre quency can by selected by pressing t he

Level key and Frequency key, respectively.

2.2.10 Inductance Measurement

Select the L/C/Z/DCR key to Ls or Lp mode for measuring the
inductance in serial mode or parallel mode. If the serial mode (Ls) is
selected, the D, Q and ESR can be shown on the seconda ry display.
If the parallel mode (Lp) is selected, only the D and Q can be shown
on the secondary display. The following shows some examples of
capacitance measurement:

The testing level and fre quency can by selected by pressing t he

Level key and Frequency key, respectively.

28





2.3 Accessory Operation

Follow the figures below to attach the test probes for making
measurement.

Shorting Bar

TL885A SMD Test Probe

29



H

H

P

C

C

L

L

P



TL885B 4-Wire Test Clip

TL08C Kelvin Clip

30

R

H

CUR

H

POT

DUT

(b) BLOCK DIAGRAM

DUT

V

A

Co

o

L

o

RoL

o

(a) CONNECTION

(c) TYPICAL IMPEDANCE MEASUREMENT RANGE(£[)

2T

1m 10m 100m 1 10 1K 10K 100K 1M100 10M

L

POT

L

CUR

4. Application

4.1 Test Leads Connection

Auto balancing bridge has four terminals (H

) to connect to the device under test (DUT). It i s important to

L

POT

CUR

, H

POT

understand what connection method will affect the measurement
accuracy.



2-T e rminal (2T)
2-T erminal is the easiest way to connect the DUT , but it contents
many errors which are the inductor and resi stor as well as the
parasitic capacitor of the test leads (Figure 3.1). Due to these
errors in measurement, the effective impedance measurement

Ω

range will be limited at 100

to 10KΩ.



3-T e rminal (3T)

Figure 3.1

, L

CUR

and

31

DUT

V

A

(d) 2T CONNECTION WITH SHILDING

H

CUR

H

POT

DUT

(b) BLOCK DIAGRAM

DUT

V

A

Co

Ro

Lo

Ro Lo

Co doesn't
effect
measurement
result

(a) CONNECTION

(c) TYPICAL IMPEDANCE MEASUREMENT RANGE(£[)

3T

1m 10m 100m 1 10 1K 10K 100K1M100 10M

L

POT

L

CUR

3-Terminal uses coaxial cable to reduce the effect of the
parasitic capacitor (Figure 3.2). The shie ld of the coaxial cable
should connect to guard of the instrument to increase the

Ω

measurement range up to 10M

.

Figure 3.2



4-T e rminal (4T)
4-Terminal connection reduces the effect of the test lead

32

H

CUR

H

POT

DUT

(b) BLOCK DIAGRAM

DUT

V

A

(a) CONNECTION

(c) TYPICAL IMPEDANCE MEASUREMENT RANGE (£[)

4T

1m 10m 100m 1 10 1K 10K 100K 1M100 10M

L

POT

L

CUR

resistance (Figure 3.3). This connection can improve the

Ω

measurement range down t o 10m

. However, the effect of the

test lead inductance can’t be eliminated.

Figure 3.3



5-T e rminal (5T)
5-Terminal connection is the combination of 3T and 4T (Figure

3.4). It has four coaxial cables. Due to the advanta ge of the 3T
and 4T, this connection can widely increase the measurement
range for 10m

Ω

to 10MΩ.

33

(d) WRONG 4T CONNECTION

H

POT

DUT

(b) BLOCK DIAGRAM

(a) CONNECTION

(c) TYPICAL IMPEDANCE MEASUREMENT RANGE (£[)

5T

1m 10m 100m 1 10 1K 10K 100K 1M100 10M

H

CUR

DUT

V

A

DUT

V

A

L

POT

L

CUR



4-T e rminal Path (4TP)
4-Termina l Path connection solves the problem that caused by
the test lead inductance. 4TP uses four coaxial cables to isolate
the current path and the vol tage sense cable (Figure 3.5). The
return current will flow through t he coaxial ca ble as well as the

Figure 3.4

shield. Theref ore, the magnet ic flux that generated by i nternal
conductor will cancel out the magnetic flux generated by
external conductor ( shield). The 4TP connection increase s the

34

(b) BLOCK DIAGRAM

(a) CONNECTION

DUT

V

A

(c) TYPICAL IMPEDANCE

MEASUREMENT RANGE(£[)

4T

1m 10m100m 1 10 1K 10K 100K 1M100 10M

H

POT

DUT

H

CUR

L

CUR

L

POT

H

POT

DUT

H

CUR

L

CUR

L

POT

(d) 4T CONNECTION W ITH SHILDING

measuremen t range from 1mΩ to 10MΩ.



Eliminating the Effect of the Parasitic Capacitor
When measuring the high impedance component (i.e. low
capacitor), the par asitic capacitor becomes an important issue
(Figure 3.6). In figure 3.6(a), the parasitic capacitor Cd is
paralleled to DUT as well as the Ci and Ch. To correct this
problem, add a guard pla ne (F igure 3.6(b)) in be twee n H and L
terminals to break the Cd. If the guard plane is connected to
instrument guard, t he effect of Ci a nd Ch will be removed.

Figure 3.5

35

HCUR HPOT LPOT LCUR

HCUR HPOT LPOT LCUR

Cd

DUT

Ch Cl

(a) Parastic Effect

Guard

Plant

Connection

Point

Ground

(b) Guard Plant reduces

Parastic Effect

Figure 3.6

4.2 Open/Short Compensation

For those precision impeda nce mea suri ng instr ument, the ope n and
short compensation nee d to be used to reduce the paras itic effect of
the test fixture. The parasitic effect of the test fixture can be treated
like the simple passive components in figure 3.7(a). When the DUT

ω

is open, the instrument gets the conductance Yp = Gp + j

Cp

(Figure 3.7(b)). When the DUT is short, the instrument gets the

ω

impedance Z s = Rs + j

Ls (Figure 3.7(c)). After the open and short

compensation, Yp and Zs are for calculating the real Zdut ( Figure

3.7(d)).

36

H

CUR

H

POT

L

CUR

L

POT

Zdut

C

o

R

s

L

s

G

o

Z

m

Redundant
Impedance

(Z

s

)

Parastic
Conductance

(Y

o

)

Parastic of the Test Fixture

(a) Parastic Effect of the Test Fixture

H

CUR

H

POT

L

CUR

L

POT

C

o

R

s

L

s

G

o

(b) OPEN Measurement

Y

o

OPEN

Y

o

= G

o

+ j£sC

o

1

(R

s

+ j£s<< )

G

o

+j£sC

o

H

CUR

H

POT

L

CUR

L

POT

C

o

R

s

L

s

G

o

(c) SHORT Measurement

Z

s

SHORT

Z

s

= Rs + j£sL

s

Figure 3.7

37

Zs

Zm

Yo Zdut

(d) Compensation Equation

Figure 3.7 (Continued)

4.3 Selecting t h e Series or Para llel Mode

According to different measuring requirement, there are series
and parallel modes to describe the measurement result. It is
depending on the hi gh or low i mpeda nce va lue t o deci de what
mode to be used.



Capacitor
The impedance and capacitance in the capacitor are negatively
proportional. Therefore, the large capacitor means the low
impedance; the small capacitor means the high impedance.
Figure 3.8 shows the equivalent circuit of capacitor. If the
capacitor is small, the Rp is more i mportant than the Rs. If the
capacitor is large, the Rs shouldn’t be avoided. Hence, uses
parallel mode to measure low capacitor and series mode to
measure high capacitor.

Zdut =
1-(Z

Zm - Zs

m-Zs)Yo

38

R

C

R

Effect

No Effect

Large capacitor

R

P

C

R

Effect

Figure 3.8

Small capacitor
(High impedance)

(Low impedance)



Inductor
The impedance and inductive in the inductor are positively
proportional. Therefore, the large inductor equals to the high
impedance and vice versa. Figure 3.9 shows the equivalent
circuit of inductor. If the inductor is small, the Rs is more
important than the Rp. I f the inductor is large, the Rp s hould be
taking care of. So, uses series mode to measure low inductor and
parallel mode to measure hi gh inductor.

P

S

No Effect

S

39

R

P

L

R

(High impedance)

No Effect

R

P

L

R

Large inductor

Effect

S

Figure 3.9

Small inductor
(Low impedance)

No Effect

S

Effect

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