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
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Electrical Data
IRC
Type
Power
Rating @
20°C
(watts)
Resistance
Range
(ohms)
Limiting
Element
Voltage
(volts)
In Air
2M to 100G
2M to 150G
4K
14K
In Oil
8K
28K
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)
F43
F44
0.7
1.3
-2000
-2000
2, 5, 10
2, 5, 10
EIA 2%
values
preferred
44
33
-55 to 100
-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 SF
6
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.
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.
Wire and Film Technologies Division
• 4222 South Staples Street • Corpus Christi Texas 78411 USA
Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com
A subsidiary of
TT electronics plc
F Series Issue October 2008 Sheet 1 of 3
High Voltage Thick Film
Resistor
Environmental Data
Typical
Load @ Rated
Power
(1000 hrs @ 20°C)
∆R%
1
Shelf Life
(12 months @ room
temperature)
∆R%
0.5
Derating From
Rated Power @ 20°C
zero at 100°C
Noise
(µV/V in decade of
frequency)
<2.5
Voltage Coefficient
of Resistance
(ppm/volt)
<25
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 SF
6
. 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.
Physical Data
L
F44D
d dia.
D
L
L
F44TU
F44KU
Dimensions (Inches and (mm))
IRC
Type
F43D
F44D
F43KU
F44KU
F43TU
F44TU
L
max
1.00
(25.4)
2.0
(50.8)
1.19
(30.2)
2.09
(53.2)
1.28
(32.6)
2.19
(55.6)
D
max
0.330
(8.4)
0.330
(8.4)
0.335
(8.5)
0.335
(8.5)
0.335
(8.5)
0.335
(8.5)
T
min
1.260
(32.0)
1.260
(32.0)
1.260
(32.0)
d
nom
0.331
(0.8)
0.331
(0.8)
0.331
(0.8)
PCB
mounting
centers
1.252
(31.8)
2.252
(57.2)
Min
Bend
Radius
0.047
(1.2)
0.047
(1.2)
Weight
nom
(g)
3.1
5.6
3.9
7.4
5.8
8.2
Wire and Film Technologies Division
• 4222 South Staples Street • Corpus Christi Texas 78411 USA
Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com
F Series Issue October 2008 Sheet 2 of 3
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.
Ordering Data
Specify type, reference, etc. as indicated in this example of type F44KU,
6.8Ω, 2% resistor.
Sample Part No.
IRC Type
Termination
Value
Tolerance
F44
KU
6806
G
50
BLK
G = ±2%, J = ±5%, K = 10%
Temperature Coefficient
Packaging
Bulk = 25 pieces per box
Wire and Film Technologies Division
• 4222 South Staples Street • Corpus Christi Texas 78411 USA
Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com
F Series Issue October 2008 Sheet 3 of 3