RdF Corporation’s history goes back to 1939. MIT Professors Arthur C. Ruge and Alfred V. deForest formed Ruge-deForest, Inc. to develop and market the bonded resistance wire strain gage invented by Professor Ruge in 1938. Similar surface resistance temperature sensors were also developed. The strain gage business was sold to BLH in 1955. The temperature measurement division relocated to Hudson, NH in 1959 and was renamed RdF Corporation. RdF is still a closely held corporation with stockholders involved in daily operations.
Design and Manufacturing:
RdF products have a reputation for ruggedness, quality and reliability gained from many years of experience in actual operational service. This reputation and the success of RdF temperature sensors is the result of our adherence to time proven design principles, our ability to work closely with our customers to assure compliance with specific operational requirements, and close attention to details in robust manufacturing processes.
Quality Assurance System:
RdF received ISO 9001 certification in March 1996, and ISO 9001-2000 certification in April 2002. Prior to ISO, the RdF quality system met the requirements of Mil-I-45208A. It also incorporated several customer specific supplements, some of which carried requirements to higher quality specifications. Other approvals are to specific NASA requirements and Federal Aviation Regulations, in particular FAR Part 21.303 for aircraft parts.
_RdF sensors have been qualified on many military and aerospace programs to the environmental requirements of MIL-STD-810. Qualification testing to the requirements contained in RTCA DO-160 has also been done. Test and calibration equipment used at RdF meet the standards of ANSI/NCSL-Z540.1-1994, and all calibrations supplied are traceable to National Institute of Standards and Technologies (NIST).
_We meet 10CFR50 Appendix B, CSA-Z299.1 for nuclear programs. We are NUPLC Certified.
RdF Technology, Markets and Specialized Products:
The technologies utilized by RdF for use in its aircraft and aerospace products include fine wire-wound or thin film platimum RTD elements, other wire RTD elements and thermistors. Patented foil and small wire Stikon® surface thermocouples are an RdF exclusive. Complimenting these sensor products are laminated etched foil heaters, Microfoil® heat flux sensors, radiometers/calorimeters, and fine etched foil resistive bridge networks.
_The information and photos that follow show basic specifications, physical configurations and applications of RdF sensors. Custom sensors are assigned their own part number identifying the specific sensor characteristics meeting your needs.



A. Cryogenic RTD
B. Hollow Annulus High Pressure LH2 RTD
C. Hollow Annulus LH2 RTD
D. 1/8" Diameter LN2 RTD

RdF’s exclusive hollow annulus elements
combine superior time response, high pressure
capability and ruggedness for cryogen at high
flow rate.

Temperature Range
–286 to 260°C (–450 to 500°F)

Stainless Steel, Inconel


Platinum fine wire:
0.003923 Ω/Ω/°C, required for LH2
0.00385 Ω/Ω/°C, applicable for LN2

Platinum thin film:
0.00385 Ω/Ω/°C, applicable for LN2

Pressure Rating
Up to 20,000 psi

>50g, 20 to 2000 Hz

Resistance @ 0°C
100,1000,1380, 2500Ω

Time Constant
<0.5 seconds


Surface Sensors

A. Thin Film Capsule Bolt-on RTD
B. Strap-on Thin Film Capsule RTD
C. Axial Lead Thin Film RTD
D. Thin Film Board Mount RTD
E. REF Grade wire-wound Bridge RTD
F. Thin FIlm Surface RTD

RdF’s unique thin film and flat wire surface
RTD designs employ proprietary processes
to provide sealed, fast, tough, small flexible
sensors to conform to any specified surface

Temperature Range
–200 to 340°C (–320 to 645°F)

Kapton® covers
Polyimide laminated
PFA Teflon® fused
FEP Teflon® fused


Platinum thin film:
0.00385 Ω/Ω/°C

Platinum fine wire:
0.003924 Ω/Ω/°C

>50g RMS, 20 to 2000 Hz

Resistance @ 0°C
100, 500, 1000, 2000Ω

Time Constant
<0.3 seconds on metal surfaces



A. PT6 Turbine Engine Thermocouple
B. PT6 Turbine Engine Thermocouple
C. Hot Gas Fine Wire Sensor
D. PW100 Turbine Engine Thermocouple

Temperature Range
–54 to 1260°C (–65 to 2300°F)

K Chromel-Alumel
T Copper-Constantan
E Chromel-Constantan
J Iron-Constantan

Stainless Steel

Grounded, Ungrounded or Exposed junction



A. Environmental System Sensor
   (Flange Mounted)
B. Environmental System Sensor
    (Thread Mount)
C. Turbine Engine Oil Temperature
    Sensor w/Full Bridge Circuit
D. Turbine Engine Oil Temperature

RdF packages these sensors for use in numerous aircraft applications.

High purity platinum RTD or Thermistor

Pressure Rating
Up to 20,000 psi

Temperature Range
–54 to 316°C (–65 to 600°F)

Case Materials
Stainless Steel

50 g, 20 to 2000 Hz



A. Logging Sensor
B. Military Vehicle Coolant RTD Sensor
C. Fast Response Appliance RTD
D. Hydraulic Fluid Sensor RTD

The applications for these sensors include Military vehicles, high pressure down hole logging, fast response food service machines and high pressure hydraulic line temperature.


Platinum fine wire:
0.003923 Ω/Ω/°C
0.00385 Ω/Ω/°C

Platinum thin film:
0.00385 Ω/Ω/°C

Case Materials
Stainless Steel

Pressure Rating
Up to 20,000 psi

Temperature Range
–54 to 316°C (–65 to 600°F)


Thermal Sensors:
Radiometers &
Heat Shield Plugs

A & C. Radiometers
B, D & E. Heat Shield Plugs

Calorimeters, Radiometers:

RdF exclusive foil, thin thermopile

Heat sink material
OFHC Copper, Aluminum (water cooled)

0 – 40 ± 10 mV nominal, typical flight channel

0 – 60 Btu/ft2 sec

Temperature Range
–185 to 260°C (–300 to 500°F)

Time Constant
0.02 seconds, typical

Heat Shield Plugs:

Tungsten-Rhenium Thermocouples
with RdF proprietary thin insulation
to 2200°C (4000°F)
Chromel-Alumel insulated thermocouples

Body Materials
A variety of phenolics
and other ablative materials


Flex Heaters

Kapton®/FEP construction
Kapton®/Polyimide construction

Temperature Range
–100°C to 200°C (FEP)
–100°C to 350°C (Polyimide)

Resistance Tolerance

Watt Density
up to 40 W/in2, typical
up to 80 W/in2, Polyimide to 200°C

0.010" maximum over heater

0.3" minimum bend radius

TML <1%, CVCM <0.1%

Stranded nickel plated copper,
TFE Teflon® insulation per MIL-W-16878
Kapton® insulation

Dielectric Strength
1250 VAC

Maximum Size
6" x 11"


Foil Bridge
& Compensation

A. Bridge Completion
B & C. Compensation circuits

Element Materials

Temperature Sensitive:

Non-Temperature Sensitive:

Kapton® film with acrylic or polymide appropriate for temperature range. Small laminated foil circuits to provide bridge completion and load cell compensation capability. Bridge Completion units can be provided for use with up to 3 active resistance sensors, strain and/or temperature. Load cell compensation for any or all of the following can be provided: Temperature, Young's Modulus, Bridge Balance and Sensitivity.