General Note
IRC reserves the right to make changes in product specification without notice or liability.
All information is subject to IRC’s own data and is considered accurate at time of going to print. A subsidiary of
TT electronics plc
• 4222 South Staples Street • Corpus Christi Texas 78411 USA
Wire and Film Technologies Division
Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com
High Voltage Thick Film
Resistor
F Series
• Termination variants
• Wide resistance range
• Good resistance stability
• Working voltage up to 28KV
• Sets available with matched characteristics
• Good ratio matching over wide voltage range
• Series connection of resistors by screw terminals
Electrical Data
IRC
Type
Power
Rating @
20°C
(watts)
Resistance
Range
(ohms)
Limiting
Element
Voltage
(volts)
TCR
(±ppm/°C)
(values>1G:
TCR is 250ppm/°C)
Resistance
Tolerance (%)
(measured at 100
volts dc)
Values
(any value to
special order)
Thermal
Impedance
(°C/watt)
Operating
Temperature
Range (°C)
In Air In Oil
F43 0.7 2M to 100G 4K 8K -2000 2, 5, 10 EIA 2%
values
preferred
44 -55 to 100
F44 1.3 2M to 150G 14K 28K -2000 2, 5, 10 33 -55 to 100
CONSTRUCTION:
The Cermatox® sintered oxide based resistive thick film is fired
onto the surface of a high quality ceramic onto which turned
brass end caps are pressed. A helical cut is made into the film
to adjust its ohmic value and finally a sleeve is fitted to provide
mechanical protection and electrical insulation. Resistors for use
in oil or SF6 can be supplied with a lacquer protection instead
of the sleeve.
TERMINATIONS:
Three styles of termination are available to permit resistors to
be screwed together in a series chain, with the end members
having axial wires for soldering.
Wire Terminations: Styles D and KU. See illustration.
Material: Solder-coated copper wire.
Screw Terminations: Styles D and KU. See illustration.
Material: Turned brass.
Screw Thread: All caps are tapped UNF-10 x 4.2 deep. UNF-
10 is 32 TPI, 60° thread angle 4.72±0.07 mm outside diameter,
3.83 mm core diameter.
Coupling Stud: All KU & TU resistors are supplied with 8 mm
long screwed brass studs.
MARKING:
Type reference, resistance value, tolerance and data code are
legend marked.
SOLVENT RESISTANCE:
The lacquer and protective sleeve provide excellent resistance
to all normal industrial cleaning solvents suitable for printed
circuits.
F Series Issue October 2008 Sheet 1 of 3
• 4222 South Staples Street • Corpus Christi Texas 78411 USA
Wire and Film Technologies Division
Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com
Dimensions (Inches and (mm))
IRC
Type
L
max
D
max
T
min
d
nom
PCB
mounting
centers
Min
Bend
Radius
Weight
nom
(g)
F43D 1.00
(25.4)
0.330
(8.4)
1.260
(32.0)
0.331
(0.8)
1.252
(31.8)
0.047
(1.2) 3.1
F44D 2.0
(50.8)
0.330
(8.4)
1.260
(32.0)
0.331
(0.8)
2.252
(57.2)
0.047
(1.2) 5.6
F43KU 1.19
(30.2)
0.335
(8.5)
1.260
(32.0)
0.331
(0.8) 3.9
F44KU 2.09
(53.2)
0.335
(8.5) 7.4
F43TU 1.28
(32.6)
0.335
(8.5) 5.8
F44TU 2.19
(55.6)
0.335
(8.5) 8.2
L
F44D
D
d dia.
F44TU
L
F44KU
L
Physical Data
Environmental Data
Typical
Load @ Rated
Power
(1000 hrs @ 20°C)
∆R%
Shelf Life
(12 months @ room
temperature) ∆R%
Derating From
Rated Power @ 20°C
Noise
(µV/V in decade of
frequency)
Voltage Coefficient
of Resistance
(ppm/volt)
1 0.5 zero at 100°C <2.5 <25
High Voltage Thick Film
Resistor
APPLICATION NOTES:
Due to the high voltage which can appear between the
end cap and any adjacent metal part, resistors should be
mounted at an adequate distance from other conductors.
Resistors may be screwed together as a stick to provide an
assembly which will be capable of withstanding any desired
voltage, providing no individual resistor is subjected to a
greater stress or power dissipation than is recommended
in this data sheet.
For some high voltage applications it is required to immerse the
components in oil or gas to reduce the effects or corona and surface
tracking. A special lacquer is available, suitable for immersion in
transformer oil or SF6. When resistors are required to be plotted,
the preferred encapsulant is a silicone compound.
For voltage dividers with a low resistance section below the medium
available value of an F43 resistor, it is entirely suitable to use an
RC Series resistor, available down to 1 ohm.
F Series Issue October 2008 Sheet 2 of 3
• 4222 South Staples Street • Corpus Christi Texas 78411 USA
Wire and Film Technologies Division
Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com
Sample Part No.
IRC Type
Termination
Value
Tolerance
G = ±2%, J = ±5%, K = 10%
Temperature Coefficient
Packaging
Bulk = 25 pieces per box
Ordering Data
F44 KU 6806 G 50 BLK
High Voltage Thick Film
Resistor
MATCHED SETS:
Matched sets can be supplied for use as voltage dividers. These may be screwed together to form sticks and, by selecting the KU
type of termination, a wire connection can be provided at each end of the stick.
Inquiries are welcome for special resistors and sets when resistor length, operating voltage or resistance values is outside
the catalog range.
Specify type, reference, etc. as indicated in this example of type F44KU,
6.8Ω, 2% resistor.
F Series Issue October 2008 Sheet 3 of 3
