Strain Gages
1
Strain Gages
General Purpose
For Waterproof & Concrete Applications
For Composite Materials, PC Boards & Plastics
Ultra-small Strains for High, Low Temperature
High Elongation & Bending Strain Gages
For Hydrogen Gas Environment
Gages with a Protector
Crack Gages
Adhesives & Coating Agents
Note
When using for special purposes, contact us.
For prices and delivery date, contact us.
1
-1
STRAIN GAGES
Strain Gages
■Strain, Stress, and Poisson's Ratio
D
P
ΔL
2
D− ΔD
− ΔD
2
Fig. 1
− ΔD
2
STRAIN GAGES
When a material receives tensile force P, it has
stress σ that corresponds to the applied force. In
proportion to the stress, the cross section contracts
and the length elongates byΔL from the length L the
material had before receiving the tensile force (See
illustration in Fig. 1) below.
P
For example, if tensile force makes 100 mm long
material elongate by 0.01 mm, the strain initiated in
the material is as follows:
ε= ΔL
L
σ = Eε
ΔD
2
D
Δ
− L
2
D＋Δ D
ΔD
2
P
L− ΔL
P
Δ
− L
2
L
(Compression)
The ratio of the elongation to the original length is
called a tensile strain and is expressed as follows:
ε= ΔL
L
ε:Strain
L:Original length
ΔL:Elongation
See the lower illustration in Fig. 1. If the material
receives compressive force, it bears compressive
strain expressed as follows:
ε= -ΔL L
1-1
σ: Stress
E: Young's modulus
ε: Strain
L＋Δ L
(Tension)
0.01
= 0.0001 = 100 μm/m
100
Thus, strain is an absolute number and is expressed
with a numeric value with x10 -6 strain, με or μm/m
suffixed.
Based on Hooke's law, the relation between stress
and the strain initiated in a material by the applied
force is expressed as follows:
ΔL
2
L
=
Stress is thus obtained by multiplying strain by the
Young's modulus. When a material receives tensile
force P, it elongates in the axial direction while
contracting in the transverse direction. Elongation
in the axial direction is called longitudinal strain and
contraction in the transverse direction, transverse
strain. The absolute value of the ratio between
the longitudinal strain and transverse one is called
Poisson's ratio, which is expressed as follows:
ε2
ν= ε1
ν:Poisson's ratio
ε1:Longitudinal strain ΔLL
ΔL（See Fig. 1）
or L
Δ
D
Δ
D
（See Fig. 1）
ε2:Transverse strain - D or D
Poisson's ratio differs depending on the material.
For major industrial materials and their mechanical
properties including Poisson's ratio, refer to page 9-1.
1
-2
A strain gage detects a minute dimensional change (strain) as an electric signal. By measuring strain
strain gage is used in various industries including machinery, automobile, electric, civil engineering,
medical, and food.
The strain gage is also adopted as a sensing element of force, pressure, acceleration, vibration,
displacement, and torque transducers used for various purposes including measurement and
control of production lines.
Kyowa produced the first Japanese-made strain gages in 1951, and based on the abundant
STRAIN GAGES
with the gage bonded to a material or structure, the strength or safety can be known. Thus, the
experience and technology accumulated for these years, the company manufactures a variety of
high-performance, environmentally friendly strain gages.
■Structure of Foil Strain Gage
Each metal has its specific resistance. If external
tensile force (compressive force) increases (decreases)
the resistance by elongating (contracting) it. Suppose
the original resistance is R and the strain-initiated
change in resistance is ΔR. Then, the following
relation is concluded:
The foil strain gage has metal foil photo-etched in a
grid pattern on the electric insulator of the thin resin
and gage leads attached, as shown in Fig. 2 below.
ΔR
R
= Ks ·
ΔL
L
The strain gage is bonded to the measuring object
with a dedicated adhesive. Strain occurring on
the measuring site is transferred to the strain
sensing element via the gage base. For accurate
measurement, the strain gage and adhesive should
match the measuring material and operating
conditions including temperature. For the bonding
method and dampproof treatment, refer to page 9-9.
= Ks ε
·
where, Ks is a gage factor, expressing the coefficient
of strain gage sensitivity. General purpose strain
gages use copper-nickel or nickel-chrome alloy for
the resistive element, and the gage factor provided
by these alloys is approximately 2.
STRAIN GAGES
■Principle of Strain Gages
■Types of Strain Gages
Types of strain gages include foil strain gage, wire
strain gage, and semiconductor strain gage.
Fig. 2 Example of KFG gage
Base length
Grid length (strain sensing part)
Laminate
Base
Base width
Grid width
(Gage length)
Center mark
Base Metal foil
Laminate film
Bonded surface
Solder
Gage leads (Silver-clad copper wire,
0.12 to 0.16 mm and 25 mm long)
1-2
1
-3
STRAIN GAGES
STRAIN GAGES
Strain initiated resistance change is extremely small.
Thus, for strain measurement a Wheatstone bridge is
formed to convert the resistance change to a voltage
change. Suppose in Fig. 3 resistances (Ω) are R1, R2,
R3 and R4 and the bridge voltage (V) is E. Then, the
output voltage eo (V) is obtained by the following
equation:
e0 =
R 1R 3 − R 2 R 4
·E
(R1＋R 2) (R 3＋R 4)
Suppose the resistance R1 is a strain gage and it
changes by ΔR due to strain. Then, the output
voltage is,
e0 =
（R1＋ΔR）R3 -R2R4
·E
(R1＋ΔR＋R2) (R3＋R4)
If R1 = R2 = R3 = R4 = R in the initial condition,
2
2
e0 = R ＋RΔR-R · E
(2R＋ΔR) 2R
Since R may be regarded extremely larger thanΔR ,
ΔR
1
e0 ≒ 41 ·
· E = · Ks ·ε· E
4
R
Thus obtained is an output voltage that is proportional
to a change in resistance, i.e. a change in strain.
This microscopic output voltage is amplified for
analog recording or digital indication for strain
measurement.
1-3
Fig. 3
R1
R2
Strain gage
R4
R3
Output voltage e0
■Principle of Strain Measurement
Bridge voltage E
■Strain Gage Wiring System
A strain gage Wheatstone bridge is configured
with a quarter, half, or full bridge according to the
measuring purpose. The typical wiring systems are
shown in Figs. 4, 5 and 6. For varied strain gage
bridge formation systems, refer to pages 9-7, 9-8.
●Quarter bridge system (1-gage system)
With the 1-gage system, a strain gage is connected
to one side of the bridge and a fixed resistor is
connected to each of the other 3 sides. This system
can easily be configured, and thus it is widely used
for general stress or strain measurement. The 1-gage
2-wire system shown in Fig. 4-1 is largely affected
by leads. Therefore, if a big temperature change is
expected or if the lead wire length is long, then the
1-gage 3-wire system shown in Fig. 4-2 must be used.
For the 1-gage 3-wire system, refer to "Compensation
Method of Temperature Effect of Lead Wires" (page
9-4).
1
-4
STRAIN GAGES
Fig. 5-2
Fig. 4-1
R
gage
( Strain
Active gage)
eo
Rg
R
R
R
Rg1
eo
Fig. 4-2
R
E
R
Rg
R
Opposite side 2-active-gage 2-wire system
R
●Full bridge system (4-gage system)
E
●Half bridge system (2-gage system)
With the 2-gage system, 2 strain gages are connected
to the bridge, one each to adjacent or opposite
sides with fixed resistor inserted in the other sides.
See Figs. 5-1 and 5-2. There exist the active-dummy
system, where one strain gage serves as a dummy
gage for temperature compensation, and the activeactive system, where both gages serve as active
gages. The 2-gage system is used to eliminate strain
components other than the target strain; according
to the measuring purpose, 2 gages are connected
to the bridge in different ways. For details, refer to
"How to Form Strain Gage Bridges" (pages 9-7. 9-8).
Fig. 5-1
See Fig. 6. The 4-gage system has 4 strain gages
connected one each to all 4 sides of the bridge. This
circuit ensures large output of strain gage transducers
and improves temperature compensation as well as
eliminates strain components other than the target
strain. For details, refer to "How to Form Strain Gage
Bridges" (pages 9-7. 9-8).
Fig. 6
Rg2
Rg1
eo
Rg3
Rg4
Rg2
Rg1
eo
gage
( Strain
Active gage)
E
eo
Strain gage
gage
(Strain
Active gage)
Rg2
STRAIN GAGES
Strain gage
(
Strain gage
Dummy gage
or active gage
)
E
R
R
E
2-gage system
1-4
1
-5
STRAIN GAGES
■Self-temperature-compensation Gages
(SELCOM Gages)
STRAIN GAGES
When receiving a temperature change, a strain gage
bonded to a measuring object generates an apparent
strain due to a difference in linear expansion coefficient
between the measuring object and the resistive
element of the strain gage, and a thermally-induced
resistance change of the gage element. The SELCOM
gage has a resistance temperature coefficient of the
resistive element adjusted to match with the measuring
object, thereby minimizing the apparent strain.
Virtually all Kyowa's strain gages are SELCOM gages,
and if bonded to suitable materials, the thermallyinduced apparent strain is within 1.8 μm/m per °C in
a temperature range of 10 to 80°C. As shown in Fig. 7,
the thermally-induced apparent strain of KFG gages
is within μm/m per °C in a temperature range of 20 to
40°C in which they are most frequently used. For the
principle of SELCOM gages, refer to page 9-4. For the
models and applicable materials, refer to page 1-6.
■Typical characteristic curve of thermally-induced
Thermally-induced apparent strain output (μm/m)
apparent strain with KFG gage
140
er ℃
mp
m/
.8μ
1
＋
120
100
80
60
＋1μm/m per ℃
40
20
0
-20
-40
-60
Temp.（℃）
10
20
30
40
50
-1μm/m per ℃
-80
-100
-120
Adhesive：CC-33A
-140
Fig. 7
1-5
60
70
80
-1.8
μm
/m
per
℃
90
100
■The following are described
in Technical Notes(pages from 9-1)
· Mechanical properties of industrial materials
· Linear expansion coefficients of materials
· Examples of strain gage measurement
· Tensile and compressive stress measurement
· Bending stress measurement
· Equations to obtain strain on beams
· Torsional and shearing stress measurement
· Temperature effect of lead wires with 2-wire system
· Effect of insulation resistance
· Resistance change of strain gages bonded to
curved surfaces
· Compensation of gage factors
· Misalignment effect
· Compensation of lead wire extension effect
· Compensation of nonlinearity of 1-gage system
· Method of obtaining the magnitude and
direction of principal stress (Rosette analysis)
· Generating calibration values based on tip
parallel resistance method.
1
-6
■Strain Gage Model Name Coding System
Applicable linear expansion coefficient
Gage Length (mm)
Suffix N indicates base and grid
widths are narrow.
Type and Length of lead wire Cable
Series Designation
KFG-2-120-C1-11 L1M3R
Applicable linear expansion
coefficient ( x10–6/°C )
KFG: General-purpose Foil Strain Gages
KFGT: Foil Strain Gages with a Temperature Sensor
KFR: Foil Strain Gages
KFW: Waterproof Foil Strain Gages
KFWS: Small-sized Waterproof Foil Strain Gages
KCW: Weldable Waterproof Foil Strain Gages
KC: Wire Strain Gages
KM: Embedded Strain Gages
A1: Uniaxial, leads at one end (KC, KTB gages)
Amber (1.1)
C2: Uniaxial 90°, lead at both ends
Diamond (1.2)
C3: Uniaxial 0°, lead at both ends
C9: Uniaxial, leads at one end (KFN gage)
Silicon (2.3)
C12: Uniaxial, 2-element, 2 mm thick (KFF gage)
Sulfur (2.7)
C15: Uniaxial right 45°, for shearing strain, leads at one end
C16: Uniaxial left 45°, for shearing strain, leads at one end
C20: Uniaxial, leads at a side (For bolt axial tension)
KFRS Foil Strain Gages for Printed Boards
D1: Biaxial 0/90°, lead at both ends
KFP: Foil Strain Gages for Plastics
D2: Biaxial 0/90°, lead at both ends (For torque)
D3: Triaxial 0/90/45°, lead at both ends, plane arrangement
KSP: Semiconductor Strain Gages
D4: Triaxial 0/120/240°, plane arrangement
KSN: Self-temperature-compensation
D6: Quadraxial 0/30/90/150°, plane arrangement
D9: Uniaxial 5-element 90°
D16: Biaxial 0/90° stacked rosette, round base
KSPL: Ultra Linear Semiconductor Strain Gages
D17: Triaxial 0/90/45° stacked rosette, round base
KHCX: Encapsulated Strain Gages
D19: Uniaxial 5-element 0°
KHCV: Encapsulated Strain Gages
D20: Biaxial 0/90° (KFN gage)
KHCR: Encapsulated Strain Gages
D22: Triaxial 0/90/45°, plane arrangement
KHCS: Encapsulated Strain Gages
D25: Triaxial 0/90/45°, plane arrangement
D28: Triaxial 0/135/90°, plane arrangement (For boring)
KHC: Encapsulated Strain Gages
D31: Biaxial 0/90°, leads at one end (For torque)
KFU: High-temperature Foil Strain Gages
D34: Biaxial 0/90°, plane arrangement
KH: High-temperature Foil Strain Gages
KFH: High-temperature Foil Strain Gages
KFL: Low-temperature Foil Strain Gages
KFEM: Ultrahigh-elongation Foil Strain Gages
KFEL: High-elongation Foil Strain Gages
D35: Triaxial 0/90/45°, plane arrangement
D39: Biaxial 5-element 0/90°, stacked rosette
E3: Uniaxial, lead at both ends (semiconductor gage)
E4: Uniaxial, leads at one end (semiconductor gage)
E5: Uniaxial, lead at both ends with no base (semiconductor gage)
KFN: Non-inductive Foil Strain Gages
F2: Uniaxial 2-element (semiconductor gage)
KFS: Shielded Foil Strain Gages
F3: Biaxial 0/90° (semiconductor gage)
KFV: Foil Strain Gage for Hydrogen Gas Environment
G4: Uniaxial, leads at one end (KH-G4)
KFF: Foil Strain Gages for Bending Strain Measurement
G8: Uniaxial active-dummy 2-element, Inconel (For KHC)
KCH: Foil Strain Gages with a Protector
KMP: Embedded Gage
KV: Crack Gage
G9: Uniaxial active-dummy 2-element, SUS (For KHC)
5: Composite materials such as GFRP
Tungsten (4.5)
Lumber (5.0)
Molybdenum (5.2)
Zirconium (5.4)
Kobar (5.9)
6: Composite materials such as GFRP
28 Tantalum (6.6)
9: Composite materials such as CFRP, GFRP
Titanium alloy (8.5)
Platinum (8.9)
Soda-lime glass (9.2)
11: Common steel (11.7)
SUS631 (10.3)
STRAIN GAGES
KSPH: High-output Semiconductor Strain Gages
KHCM: Encapsulated Strain Gages
3: Composite materials such as GFRP
C11: Uniaxial, 2-element, 1 mm thick (KFF gage)
KMC: Concrete-embedded Strain Gages
Semiconductor Strain Gages
1: Composite materials such as CFRP
C1: Uniaxial, leads at one end (Foil gage)
KFRP: Foil Strain Gages for Composite Materials
KFML: Foil Strain Gages for low-elasticity Materials
STRAIN GAGES
Gage Pattern
Resistance (Ω)
SUS630 (10.6)
Cast iron (10.8)
Nickel-molybdenum steel (11.3)
Beryllium (11.5)
Inconel X (12.1)
13: Corrosion and heat-resistant alloys such as NCF
Nickel (13.3)
Printed board (13.0)
16: Stainless steel SUS304 (16.2)
G10: Uniaxial (For KCW)
Beryllium steel (16.7)
G12: Uniaxial active-dummy 2-element (For KHCS)
Copper (16.7)
G13: Uniaxial active-dummy 2-element (For KHCX)
G15: Uniaxial active-dummy 2-element (For KHCM)
23: 2014-T4 aluminum (23.4)
G16: Uniaxial active-dummy 2-element (For KHCR)
Brass (21.0)
G17: Uniaxial active 1-element (For KHCV)
Tin (23.0)
H1: Uniaxial (For KM-30)
2024-T4 aluminum (23.2)
H2: Uniaxial (For KM-120)
H3: Uniaxial (For KMC)
H4: Uniaxial with T thermocouple (For KMC)
27: Magnesium alloy (27.0)
Composite material, GFRP (35.0)
J1: Uniaxial (For KFS)
65: Acrylic resin (65.0)
Polycarbonate (66.6)
For choosing strain gages, refer to pages 1-7, 1-8.
For special custom-made gage patterns, refer pages 1-52, 1-53.
Note: Combination of codes is limited and menu options cannot freely be selected.
1-6
1
-7
Strain Gages Selection Chart
Selecting strain gage types matching to
measurement purpose and environment.
STRAIN GAGES
KFG-2-120Series Designation
Gage Length (mm)
Resistance (Ω)
Series Designation
Gage Length (mm)
Gage Resistance
Selecting strain gage types
matching the kind of material
and the temperature of the
environment.
Selecting gage length types
matching the kind of material
and the environment of space.
STRAIN GAGES
E.g.
· Outdoor environment,
measurement in
underwater
KFW
Main Application
Strain measurement
for mortar & concrete
Waterproof foil
strain gages
Strain measurement
for wood & glass
· Measurement under
high temperature
KFU
Strain measurement
for common steel
& acrylic
High-temperature
foil strain gages
Concentrated stress
measurement
· Concrete internal strain
measurement
Strain measurement
in narrow space.
Strain Gage
Length (mm)
30 to 120
5 to 30
Embedded
strain gages
Strain measurement
in fast phenomenon
(Impact-shock, etc.)
Application
Resistance
Bending
compensation
60Ω
Generalpurpose
strain
measurement
120Ω
For transducers
350 to
1000Ω
1 to 6
0.15 to 2
0.2 to 1
KM
0.2 to 1
For special custom-made gage patterns, refer pages 1-52, 1-53.
Note: Combination of codes is limited and menu options cannot freely be selected.
1-7
Selecting strain gage
resistance matching
the measurement
application.
1
-8
STRAIN GAGES
C1-11 L1M3R
Gage Pattern
Applicable Linear
Expansion Coefficient
Pattern of strain gages
Linear expansion
coefficient of strain
gages
Selecting a pattern matching
the measurement application.
Lead wire cable
of strain gage
Selecting a kind of lead
wire cable matching the
measuring condition under
environments and
temperature.
E.g.
STRAIN GAGES
E.g.
Selecting a pattern matching
the measurement application.
Type and Length of
Lead Wire Type Cable
5
· Concentrated
stress measurement
Wood (lumber)
D9
Uniaxial
5-element 90°
11
Common steel
· Measurement of
Poisson ratio
16
Stainless steel
Biaxial 0, 90°
stacked rosette,
round base.
2
D16
1
3
23
Aluminum alloy
27
· Stress analysis
Magnesium alloy
3
Triaxial 0, 90,
and 45°
stacked rosette,
round base.
2
D17
1
A strain gage with a
lead wire for safe
labor
We supply these two types:
・Gages with leads only
・Gages connected to flat vinyl
lead wires of required length
Gages connected to lead wires
provide increases in speed and
work required for adhesion.
Refer to the pages for each
gage for combinations of gages
and lead wires.
65 Plastics
1-8
1
-9
Strain Gages Measurement Examples
STRAIN GAGES
●Stress Measurement of precast concrete such as Tetrapods®
Wire strain gage
KC
STRAIN GAGES
Universal recorder
EDX-100A
●Stress measurement of plastic parts
General-purpose foil strain gage
KFG
Sensor interface
PCD-400A
1-9
1
-10
STRAIN GAGES
●Stress measurement when a PCB is mounted
Foil strain gages
for printed boards
KFRS
STRAIN GAGES
Sensor interface
PCD-400A
●Stress measurement during strength testing of a shutter
General-purpose foil strain gages
KFG
Universal recorder
EDX-200A
1-10
1
-11
Strain Gage Selection Chart for Each
Measurement Application.
Metal
General Stress Measurement
STRAIN GAGES
Measurement
Environment
Under general
environment
Max.
elongation
5%
Usable at up
to 150°C
Models
Crack Gages
Pages
1-18
General-purpose Foil Strain Gages
KFG
1-18
General-purpose Foil Strain Gages
KFR
1-27
Foil Strain Gages
KFW
Less coating
treatment
required
Simply
waterproofed,
long-term stability
KFWS
1-30
Up to 750°C
KCW
1-30
Weldable Waterproof Foil Strain Gages
1-45
Applicable to Sensing Element of Transducers
Models
Pages
KFG
STRAIN GAGES
1-24
General-purpose Foil Strain Gages
1-22
General-purpose Foil Strain Gages
1-20
1-21
Models
Installation
by cutting
method
KFG T-F7
Installation
by boring
method
KFG-D28
Pages
1-25
General-purpose Foil Strain Gages
General-purpose
Foil Strain Gages
Up to 650°C
Up to 550°C
Up to 350°C
Up to 350°C
Measurement under hydrogen gas environment
Measurement
Environment
Models
KFV
Measurement
under high-pressure
hydrogen gas
environment
Foil Strain Gage for Hydrogen Gas Environment
Pages
Models
KHCV
Encapsulated Strain Gages
KHCR
Encapsulated Strain Gages
KHCS
Encapsulated Strain Gages
KHCM
Encapsulated Strain Gages
KHC
Encapsulated Strain Gages
KFU
High-temperature Foil Strain Gages
KH
High-temperature Foil Strain Gages
KFH
High-temperature Foil Strain Gages
Models
Measurement at KFL
LHe temperature
Low-temperature Foil Strain Gages
(-269°C)
Models
Measurement KFS
under high
electric field
accompanying
induction noise Shielded Foil Strain Gages
1-38
1-38
1-38
1-38
1-38
1-39
1-39
1-40
Pages
1-41
Pages
1-43
Applicable to Ultra-small Strain Measurement and
Highly-Sensitive Element of Transducers
Pages
Measurement of
<100μm/m under less
temperature change
environment
Measurement of
<100μm/m under less
temperature change
environment
Measurement of
<100μm/m under less
temperature change
environment
1-44
1-38
Measurement under High Electric Field
Measurement
Environment
KFF
Foil Strain Gages for Bending Strain Measurement
Encapsulated Strain Gages
Pages
Measurement at Low-temperature
1-44
Internal Strain Measurement
Measurement
Environment
Up to 250°C
KHCX
Measurement
Environment
1-25
1-46
Models
Measurement
Environment
Residual Stress Measurement
1-11
Up to 750°C
KFG-C15, 16
KFG-D2, 31
Biaxial,
torque
measurement General-purpose Foil Strain Gages
Applicable where a
strain gage cannot
be bonded inside a
box structure
Measurement
Environment
Up to 800°C
Small-sized Waterproof Foil Strain Gages
Measurement
Environment
Pages
Measurement at High-temperature
1-29
Simply
KCH
waterproofed, Foil Strain Gages
rugged
with a Protector
Uniaxial,
High-resistance
350, 500, 1000 Ω
Uniaxial,
for shearing
strain
Measurement
of the progress
and propagation
Crack Gages
speed of crack
Up to 950°C
Waterproof Foil Strain Gages
Measurement
Environment
Models
KV
KFG
Less coating
treatment
required
Measurement
Environment
Models
Pages
KSP
1-36
Semiconductor Strain Gages
KSN
Self-temperature-compensation
Semiconductor Strain Gages
1-36
KSPL
1-37
Ultra Linear Semiconductor Strain Gages
Composite Materials, Printed
Boards, and Plastics
Impact Strain Measurement
Models
KSPH
Enable
measurement
with no amplifier
High-output Semiconductor Strain Gages
used
General Stress Measurement
Pages
1-37
Concentrated Stress Measurement
Measurement
Environment
Models
Measurement KFG-D9, 19, 39
of stress
distribution at
8mm to 12mm
intervals
Pitch: 2mm or 3mm
Measurement KFR-D9, 19
of stress
distribution at
2mm intervals
-12
Pages
1-22
1-28
Measurement
Environment
Applicable linear
expansion
coefficient 1 to
9×10 -6/°C
Applicable
linear expansion
coefficient
13×10 -6/°C
Applicable
linear expansion
coefficient
65×10 -6/°C
For polyurethane
and rubber
For strain
measurement
inside resin
Models
Pages
KFRP
1-33
Foil Strain Gages for composite Materials
KFRS
1-34
Foil Strain Gages for Printed Boards
KFP
1-35
Foil Strain Gages for Plastics
KFML
STRAIN GAGES
Measurement
Environment
1
1-35
Foil Strain Gages for Low-elasticity Materials
KMP
1-45
Embedded Gage
Pitch: 0.5mm
Measurement under High Magnetic Field
Measurement
Environment
Measurement
under DC/AC
magnetic field
Pages
KFL
1-41
Low-temperature Foil Strain Gages
High-elongation Gages
Measurement
Environment
Max. elongation
approx. 20%-30%
KFR
1-27
Max. elongation
approx. 15%
Foil Strain Gages
KFH
1-40
Models
Pages
KFEM
1-42
Ultrahigh-elongation Foil Strain Gages
KFEL
1-42
High-elongation Foil Strain Gages
High-temperature Foil Strain Gages
KFN
Non-inductive
Foil Strain Gages
1-43
Wood (lumber), Plaster, Paper, etc.
General Stress Measurement
Measurement
Environment
Models
Lumber (applicable KFG
linear expansion
General-purpose
coefficient
5×10-6/°C)
Foil Strain Gages
Concrete, Mortar, etc.
STRAIN GAGES
Measurement
under DC
magnetic field at
low temperature
Measurement
under DC
magnetic field
at middle
temperature
Measurement
under DC
magnetic field at
high temperature
Models
Metal, Plastics, Lumber and Rubber
Pages
1-19
General stress Measurement
Measurement
Environment
Less coating
treatment
required
Less coating
treatment
required
Surface strain
meas. (small
aggregate)
Models
Pages
KFW
1-29
Waterproof Foil Strain Gages
KFWS
1-30
Small-sized Waterproof Foil Strain Gages
KFG
General-purpose Foil Strain Gages
Length: 10 to 20 mm
Surface strain KC
meas. (large Wire Strain Gages
aggregate)
Length: 60 to 120 mm
KM
Internal strain
measurement
1-31
1-31
1-32
Embedded Strain Gages
Self-shrinkage KMC
strain
measurement Concrete-embedded Strain Gages
1-32
Various Materials
General Stress Measurement
Measurement
Environment
Models
Simultaneous KFGT
measurement
of strain and
temperature Foil Strain Gages with a Temperature Sensor
Pages
1-26
Metal Bolts
Measurement of Axial Tension of Bolts
Measurement
Environment
Models
KFG-C20
measuring
tightening
General-purpose
stress of bolts Foil Strain Gages
Pages
1-25
1-12
1
-13
Major Properties of Kyowa Strain Gages
STRAIN GAGES
Models/
series designation
Materials
Resistive
element
Base
For general
purpose
CC-33A
CC-36
EP-340
PC-600
-196 to 120
-30 to 100
-55 to 150
-196 to 150
10 to 100
5，
11，
16，
23，
27
5.0
1.2×107
1-18
For sensing element
of transducers
PC-600
EP-340
-196 to 150
-55 to 150
10 to 100
11，
16，
23，
27
5.0
1.2×107
1-20
CC-35
-30 to 120
10 to 100
5.0
1.2×107
1-31
For concrete
General-purpose
Foil Strain Gages
CuNi alloy foil
KFG
Concentrated stress
measurement
Polyimide
For general stress measurement
Residual stress
measurement
Notes
For ultra-small strain measurement
For composite materials,
plastics and rubber
STRAIN GAGES
1-13
SelfApplicable linear Strain limit Fatigue life
Operating temperature
ranges in combination temperature- expansion at room temp. at room temp.,
Pages
with major adhesives compensation coefficient
(Approx. %) approx. (Times)
range (℃)
(x10–6/℃)
after curing (℃) *1
*2
*3
Bolt axial tension
measurement
CC-33A
CC-36
EP-340
PC-600
CC-33A
CC-36
EP-340
PC-600
Strain measurement
at middle temperaFoil Strain Gages ture; for transducers
NiCr alloy foil
KFR
Concentrated stress
measurement
Polyimide
Polyimide
Paper base +
Waterproof Foil Strain Gages
CuNi alloy foil
phenol-epoxy
KFW
Small-sized Waterproof Foil Strain Gages CuNi alloy foil
KFWS
Polyimide
Weldable Waterproof Foil Strain Gages NiCr alloy foil
KCW
Stainless steel
Wire Strain Gages
KC
CuNi alloy wire
Paper base +
phenol-epoxy
Embedded Strain Gages
KM
CuNi alloy
Acrylate
10 to 100
11，
16，
23，
27
1-22
10 to 100
11，
16，
23，
27
1-25
1-25
20 to 50
11
10 to 100
11，
16，
23
3
1×106
1-26
0 to 150
11，
16，
23
2.2
1×106
1-27
0 to 150
11，
16，
23
10 to 80
11，
16，
23
2.8
3×104
1-29
10 to 80
11，
16，
23
5.0
3×104
1-30
10 to 90
11
0.9
*A
1×106
1-30
-30 to 120
10 to 60
11
1.8
1.5×105
1-31
(Embedment)
-10 to 70
0 to 50
11
0.3
1-32
0.3
1-32
EP-180
Foil Strain Gages with a Temperature Sensor
CuNi alloy foil
KFGT
-196 to 120
-30 to 100
-55 to 150
-196 to 150
-196 to 120
-30 to 100
-55 to 150
-196 to 150
11
Room temp. to 50
CC-33A
CC-36
EP-340
PC-600
-10 to 120
-10 to 100
-10 to 120
-10 to 120
PC-600
CC-33A
EP-340
PC-600
CC-33A
EP-340
CC-33A
CC-36
EP-180
-196 to 150
-196 to 120
-55 to 150
CC-33A
EP-180
-10 to 80
-10 to 80
-196 to 150
-196 to 120
-55 to 150
-10 to 80
-10 to 80
-10 to 80
(Spot welding)
-20 to 100
CC-35
(Embedment)
Concrete-embedded Strain Gages CuNi alloy wire
KMC
Silicone
Foil Strain Gages for Composite Materials NiCr alloy foil
KFRP
Polyimide
EP-34B
CC-33A
-55 to 200
-196 to 120
Foil Strain Gages for Printed Boards
NiCr alloy foil
KFRS
Polyimide
CC-33A
PC-600
-196 to 120
-30 to 120
-196 to 150
Room temp. to 70
0 to 150
1-28
1，
3，
6，
9
2.2
1×106
1-33
13
1.6
2×106
1-34
65
3.0
1×106
1-35
EP-34B
CC-33A
CC-36
-20 to 80
-20 to 80
-20 to 80
CuNi alloy foil Phenol-epoxy
CC-33A
0 to 60
1.0
P type Si
Paper base +
phenol-epoxy
CC-33A
CC-36
-50 to 120
-30 to 100
0.3
*A
2×106
1-36
P type Si
Paper base +
phenol-epoxy
CC-33A
CC-36
-50 to 120
-30 to 100
0.3
*A
2×106
1-36
P type Si
N type Si
Paper base +
phenol-epoxy
CC-33A
CC-36
-50 to 120
-30 to 100
20 to 70
11
0.3
*A
2×106
1-36
Self-temperature-compensation
Semiconductor Strain Gages
KSN
N type Si
Paper base +
phenol-epoxy
CC-33A
CC-36
-50 to 120
-30 to 100
20 to 70
11，
16
0.3
*A
2×106
1-36
High-output
Semiconductor Strain Gages
KSPH
P type Si
Paper base +
phenol-epoxy
CC-33A
CC-36
-50 to 120
-30 to 100
0.3
*A
2×106
1-37
Ultra Linear
Semiconductor Strain Gages
KSPL
P type Si
Paper base +
phenol-epoxy
CC-33A
CC-36
-50 to 120
-30 to 100
0.3
*A
2×106
1-37
Paper base +
Foil Strain Gages for Plastics
CuNi alloy foil
phenol-epoxy
KFP
Foil Strain Gages for
Low-elasticity Materials
KFML
Ultra-small strain
measurement
Semiconductor For sensing element
Strain Gages of highly sensitive
transducers
KSP
Ultra-small strain; 2element, temperaturecompensation type
10 to 80
1-35
*1. Underlined adhesives are those used for strain limit tests at room temperature and for fatigue tests at room temperature.
*2. Typical values with uniaxial gages. Strain limit is the mechanical limit where a difference between the strain reading and mechanical strain
initiated by applying tension load exceeds 10%.
*3. Typical values with uniaxial gages. Strain level: ±1500 μm/m ; *A: ±1000 μm/m; *B: ±500 μm/m, *C: ±100 μm/m.
1
-14
For high-temperature applications
For
For antimagnetic For large strain For low
With Internal Hi-pressure
Crack protector
applications
measurement temp.
strain
H2
Resistive
element
Base
SelfApplicable linear Strain limit Fatigue life
Operating temperature
ranges in combination temperature- expansion at room temp. at room temp.,
Pages
with major adhesives compensation coefficient
(Approx. %) approx. (Times)
range (℃)
(x10–6/℃)
after curing (℃) *1
*2
*3
Encapsulated Strain Gages
KHCX
Heat-resistant
Heat-resistant
special alloy
metal
wire
(Spot welding)
-196 to 950
Encapsulated Strain Gages
KHCV
Heat-resistant
Heat-resistant
special alloy
metal
wire
(Spot welding)
25 to 800
Encapsulated Strain Gages
KHCR
Heat-resistant
Heat-resistant
special alloy
metal
wire
(Spot welding)
25 to 750
Encapsulated Strain Gages
KHCS
Heat-resistant
Heat-resistant
special alloy
metal
wire
(Spot welding)
-196 to750
Encapsulated Strain Gages
KHCM
Heat-resistant
Heat-resistant
special alloy
metal
wire
(Spot welding)
Encapsulated Strain Gages
KHC type 20
NiCr alloy wire
Encapsulated Strain Gages
KHC type 10
Heat-resistant
metal
-196 to 650
(Spot welding)
-196 to 550
11，
13
1.0
(950℃)
*C
1×106
(950℃)
1-38
(Dynamic
measurement)
1.0
(800℃)
*B
1×106
(800℃)
1-38
25 to 750
11，
13，
16
1.0
(750℃)
*B
1×106
(750℃)
1-38
25 to 750
11，
13，
16
1.0
(750℃)
*B
1×106
(750℃)
1-38
25 to 650
11，
13，
16
1.0
(650℃)
*B
1×106
(650℃)
1-38
0.8
*A
4×105
0.5
*A
4×105
25 to 950
Room temp.
to 500
1-38
11，
16
10 to 300
11，
16，
23
1.9
*A
1.5×105
(300℃)
1-39
-50 to 350
10 to 300
11，
16
0.5
*B
1×107
1-39
PC-600
EP-34B
PI-32
-196 to 250
-55 to 200
-196 to 250
10 to 250
11，
16，
23
2.1
2×105
1-40
Polyimide
PC-600
EP-270
CC-33A
-269 to 150
-269 to 30
-196 to 120
-196 to 50
5，
11，
16，
23
2.2
1×106
1-41
CuNi alloy foil
Polyimide
CC-36
-20 to 80
20 to 30
High-elongation Foil
Strain Gages
KFEL
CuNi alloy foil
Polyimide
CC-36
-10 to 80
15
1×106
1-42
Non-inductive Foil
Strain Gages
KFN
NiCr alloy foil
Polyimide
PC-600
CC-33A
-196 to 150
-196 to 120
0 to 150
11，
16，
23
1
1×104
1-43
Shielded Foil
Strain Gages
KFS
CuNi alloy foil
(120)
NiCr alloy foil
(350)
Polyimide
PC-600
CC-33A
EP-340
-196 to 150
-196 to 120
-55 to 150
10 to 100
11，
16
0.5
1×104
1-43
Foil Strain Gage for
Hydrogen Gas Environment FeCr alloy foil
KFV
Polyimide
PC-600
-30 to 80
Foil Strain Gages for Bending
CuNi alloy foil
Strain Measurement
KFF
Acrylate
CC-33A
EP-180
-50 to 80
-50 to 80
High-temperature Foil
Strain Gages
KFU
NiCr alloy foil
Polyimide
High-temperature Foil
Strain Gages
KH
NiCr alloy foil
Stainless
steel
High-temperature Foil
Strain Gages
KFH
NiCr alloy foil
Polyimide
Low-temperature Foil
Strain Gages
KFL
NiCr alloy foil
Ultrahigh-elongation Foil
Strain Gages
KFEM
Foil Strain Gages
with a Protector
KCH
CuNi alloy foil
Polyimide
Crack Gages
KV
CuNi alloy foil
Paper base+
phenol-epoxy
PI-32
-196 to 350
(Spot welding)
Protector: Stud bolt
Strain gage
EP-340，
CC-33A
-40 to 100
CC-33A
CC-36
PC-600
STRAIN GAGES
Notes
Materials
STRAIN GAGES
Models/
series designation
1-42
1-44
20 to 60
11，
16，
23
0.2
*B
4×106
1-44
11
1
*A
1.2×106
1-45
1-46
*1. Underlined adhesives are those used for strain limit tests at room temperature and for fatigue tests at room temperature.
*2. Typical values with uniaxial gages. Strain limit is the mechanical limit where a difference between the strain reading and mechanical strain
initiated by applying tension load exceeds 10%.
*3. Typical values with uniaxial gages. Strain level: 1500 μm/m; *A: 1000 μm/m; *B: 500 μm/m, *C: 100 μm/m
1-14
1
-15
Strain Gages with Pre-Attached Lead Cables
STRAIN GAGES
Virtually all Kyowa strain gages are delivered with a lead
wire cable pre-attached to ensure labor saving in gage
bonding works by eliminating the need for soldering.
Types and lengths of the lead wire cable selectable for
each gage are as follows.
Applicable Models
of Strain Gage
Length of
lead wire cable
Type of
lead wire
Cable
（＊）
15 cm
30 cm
1m
3m
5m
Model, etc.
When ordering, specify the model of the strain gage and
the code of the lead wire cable with a space in between.
e.g.
Model of Strain Gage
Code of lead wire Cable
KFG-2-120-C1-11
L1M3R
KFG, KFR, KFRP, KFP,
KFL, KFEL, and KFEM
Polyester-coated Polyester-coated
2-wire
3-wire
copper cable
copper cable
-196 to 150°C
-196 to 150°C
N15C2
N30C2
N1M2
KFG, KFR, KFW, KFWS, KC,
KFRP, KFP, KFEL, and KFEM
Vinyl-coated flat 2-wire cable
-10 to 80°C
N15C3
N30C3
N1M3
Twisted in the cases of
50 cm or longer
Vinyl-coated flat 3-wire cable
-10 to 80°C
Uniaxial
Multiaxial
Uniaxial
Multiaxial
L15C2R
L30C2R
L1M2R
L3M2R
L5M2R
L15C2S
L30C2S
L1M2S
L3M2S
L5M2S
L15C3R
L30C3R
L1M3R
L3M3R
L5M3R
L15C3S
L30C3S
L1M3S
L3M3S
L5M3S
L-6, L-9 for 6 m or longer
L-7, L-10 for 6 m or longer
Red (independent)
White
White
Red
Red
Coating colors
STRAIN GAGES
Note: KFEL and KFEM are available only with 2-wire system.
＊For other lead wire cable lengths, contact us.
Applicable Models
of Strain Gage
Type of
lead wire
cable
Length of
lead wire cable
15 cm
30 cm
1m
3m
5m
（＊）
Model, etc.
Coating colors
KFG, KFR, KFRP,
and KFL
KFN, KFS
KFRP, KFH,
and KFL
KFU, KFH
Middletemperature
2-wire cable
-100 to 150°C
Middletemperature
3-wire cable
-100 to 150°C
Vinyl-coated
low-noise
3-wire cable
-10 to 80°C
Vinyl-coated
low-noise
3-wire cable
-269 to 250°C
Hightemperature
3-wire cable
-269 to 350°C
3 strand
glass-coated
Ni clad copper wire
RT-280°C
R15C2
R30C2
R1M2
R3M2
R5M2
L-11
R15C3
R30C3
R1M3
R3M3
R5M3
L-12
J15C3
J30C3
J1M3
J3M3
J5M3
L-13
F15C3
F30C3
F1M3
F3M3
F5M3
L-3
H15C3
H30C3
H1M3
H3M3
H5M3
L-17
B15C3
B30C3
B1M3
B3M3
B5M
Contact us
Red(independent)
Red(independent)
White
Black
White
Black
Grey
Grey
Red(independent)
Blue
Blue
Black(independent)
Yellow
Green
Red(independent)
Blue
White
＊For other lead wire cable lengths, contact us.
●For concentrated stress measurement. KFR are provided standard with a lead wire cable 10 cm long.
●Encapsulated strain gages are provided standard with an MI cable 2 m long and a soft cable 50 cm long.
See page 1-30 for KCW. See page 1-32 for KM.
See page 1-34 for KFRS. See page 1-39 for KH.
1-15
1
Lead Wire Cables
-16
●L-type Lead Wire Cables
Models
Types
Conductor
Material
Nominal
Number of
Cross
Strands/
Section of
Wire
Diam.
Conductor
(mm)
2
(mm )
Reciprocating Coated
Resistance
Wire
per Meter Diameter
(Ω)
(mm)
Unit
Length
(m)
High-temperature lead wire
Room temp.
to 350°C
L-1
–10 to 80°C
L-2
–269
to 250°C
L-3
CuNi alloy
0.07
1／φ0.30
14.20
φ0.50
50
Copper
0.30
12／φ0.18
0.12
φ2.30
100
Silver-plated
copper
0.14
7／φ0.16
0.28
φ0.98
50
Nickel-clad
copper
0.20
1／φ0.50
0.18
φ0.70
30
Copper
0.50
20／φ0.18
0.07
φ2.50
Copper
0.08
7／φ0.12
0.44
φ1.00
Copper
0.08
7／φ0.12
0.44
φ1.00
Copper
0.11
10／φ0.12
0.32
φ1.00
Copper
0.11
10／φ0.12
0.32
φ1.00
Silver-plated
copper
0.08
7／φ0.12
0.44
φ0.86
Silver-plated
copper
0.08
7／φ0.12
0.44
φ0.86
Tin-plated
copper
0.09
7／φ0.13
0.46
φ3.50
Tin-plated
copper
0.08
7／φ0.12
0.48
φ4.00
Silver-plated
copper
0.08
7／φ0.12
0.48
φ2.50
Vinyl-coated flat 3-wire cable
Fluororesin-coated
high/low-temp. 3-wire cable
STRAIN GAGES
Operating
Temperature
Range
High-temperature lead wire cable
Room temp.
to 350°C
L-4
–10 to 80°C
L-5
–10 to 80°C
L-6
(*1)
–10 to 80°C
L-7
(*2)
–10 to 80°C
L-9
(*1)
–10 to 80°C
L-10 (*2)
Vinyl-coated flat 2-wire cable
Vinyl-coated flat 2-wire cable
Vinyl-coated flat 3-wire cable
Vinyl-coated flat 3-wire cable
–100
to 150°C
L-11
–100
to 150°C
L-12
–10 to 80°C
L-13
–50 to 90°C
L-14
–269
to 250°C
L-15
–269
to 250°C
–269
to 350°C
L-16
L-17
Middle-temperature
2-wire cable
Middle-temperature
3-wire cable
Vinyl-coated normal-temperature
low-noise 3-wire cable
Chloroprene-coated normal-temperature
low-noise 4-wire cable
Fluoroplastic-coated high/low-temp.
low-noise 3-wire cable
Fluoroplastic-coated high/low-temp.
low-noise 4-wire cable
High/low-temperature
3-wire cable
100
STRAIN GAGES
Vinyl-coated flat 2-wire cable
10
Silver-plated
copper
0.08
7／φ0.12
0.48
φ3.30
Nickel-plated
copper
0.07
1／φ0.30
0.50
φ0.38
30
*1. These models have a suffix R, W, G, Y or B indicating the coating color; red, white, green, yellow or black. e.g. L-6B: Black vinyl coated.
*2. These models have a suffix WR, WL or WY indicating the stripe color; red, blue or yellow on white vinyl coating. e.g.
L-7WR: Red stripes on white coating.
1-16
1
-17
Examples of vinyl-coated flat wire to connect gages
Cord
STRAIN GAGES
2-wire
Types
3-wire
C1
Red stripes
Red stripes
Cord
2-wire
Types
3-wire
D9
or
D19
or
D39
Red stripes
Red
2 kinds of connection
depends on the length
of gages.
Same as D16 and D17
Red
White
Yellow stripes
D16
C2
or
C3
Red
Red stripes
Red
White
Yellow stripes
D17
Red
re
e
n
Red stripes
Red
G
STRAIN GAGES
C15
or
C16
Red stripes
Blue stripes
Red stripes
D1
Yellow stripes
White
Red
White
Red stripes
Yellow stripes
D28
Red
Red stripes
D2
Green
Blue stripes
Red stripes
Red stripes
Red
White
Yellow stripes
D31
D4
Green
1-17
Blue stripes
Red stripes