Glass Encapsulated Thermistors

55000 Series

Maximum Continuous Use, 200°C (392°F) [Short Term Use to 250°C (482°F)]
Excellent Long Term Stability
Hermetically Sealed Glass Bead
Available in 2252, 3000, 5000 and 10,000 Ω Resistances at 25°C (77°F)
Tolerance: ±0.2°C From 0 to 70°C (32 to 158°F)
2.4 mm (0.095") Diameter Bead Max
#32 AWG, Gold Plated Dumet Leads 63.5 mm (2.5") Long

Thermistor Elements, Probes and Assemblies - View related products

Description

The OMEGA 55000 Series glass encapsulated thermistors provide a higher temperature alternative to the OMEGA 44000 Series epoxy coated thermistors where needed. With a maximum continuous temperature rating of -80 to 200°C (-112 to 392°F), and intermittent operation to 250°C (482°F), the 55000 Series thermistors can be used in those applications previously out of reach.

With the same small size as our 44000 Series thermistor, and with solderable #32 AWG gold plated Dumet leads, the 55000 Series thermistor can be used interchangeably wherever our 44000 Series thermistors are used.

Resistance Vs. Temperature Characteristics:
The Steinhart-Hart Equation has become the generally accepted method for specifying the resistance vs. temperature relationship for thermistors. The Steinhart-Hart equation for temperature as a function of resistance is as follows:

¹⁄T = A + B [Ln(R)] + C [Ln(R)]³

where: A, B and C are constants derived from three temperature test points.
R = Thermistor resistance in Ω
T = Temperature in Kelvins K (°C + 275.15)

To determine the thermistor resistance at a specific temperature point, the following equation is used:

R = e^{(beta-(alpha/2))1/3-((beta+(alpha/2))1/3}
where:
alpha = ((A-(1/T))/C)

Model Number	R25°C	A	B	C
55004	2252Ω	1.4705x10^-3	2.3780x10^-4	1.0389x10^-7
55005	3000Ω	1.4052x10^-3	2.3692x10^-4	1.0125x10^-7
55007	5000Ω	1.2870x10^-3	2.3585x10^-4	9.4346x10^-8
55016	10000Ω	1.1275x10^-3	2.3441x10^-4	8.6482x10^-8

beta = SQRT(((B/(3C))³)+(alpha²/4))

The A, B and C constants for each of our thermistor selections are shown in the table to the right. Using these constants, you can determine the temperature of the thermistor based on its resistance, or determine a thermistor's resistance at a particular temperature.

Model No. 55016 Thermistor
Operating Temperature	10 Months
0°C	<0.01°C
25°C	<0.01°C
100°C	<0.12°C
150°C	<0.15°C
200°C	<0.20°C

Stability and Drift:
Thermistors are generally very accurate and stable devices, but conditions such as over-temperature exposure, thermal or mechanical shock, or subjecting them to over-current conditions can result in a change in resistance. The 55000 Series thermistors are chemically stable and not significantly affected by aging. The following shows typical stability data for the 55016 thermistor:

Temp °C	Model No. 55004, ±0.20°C
Temp °C	±°C	±Ω
-80°C	1.00	142,000
-40°C	0.40	2018
0°C	0.20	75
40°C	0.20	10
70°C	0.20	2.7
100°C	0.30	1.3
150°C	1.00	0.9

Tolerance Curves:
Accuracy tolerances for thermistor sensors are expressed as a percentage of temperature. This is also referred to as interchangeability. The 55000 Series thermistors do have a tolerance of ±0.2°C between 0 and 70°C, but can be used across their entire temperature range.

Operating Current and Dissipation Constant:
The suggested operating current for bead-style thermistors is approximately 10 to 15 micro-amps. thermistors can experience self-heating effects if they are exposed to operating currents that are high enough to create more heat than the thermistor can dissipate to its surroundings. The 55000 Series thermistors have a dissipation constant of 1.5 milliwatts/°C in air.

Time Constant:
The time constant is the time required for a thermistor to react to a step change in temperature. For example, if exposed to a change from 0 to 100°C (32 to 212°F), the 63% time constant would be the time required for the thermistor to indicate a resistance to its value at 63°C (145°F). The time constant for the 55000 Series thermistor is less than 15 seconds in air.

Place Order(Specify Model Number)

Part Number/Desc.

Qty

Description

55004

Consult Sales

Availability:

2252 Ohms Resistance at 25°C.

55005

USD26.50

Availability: 1 week

3000 Ohms Resistance at 25°C.

55007

USD27.00

Availability: 3 weeks

5000 Ohms Resistance at 25°C.

55016

Consult Sales

Availability:

10000 Ohms Resistance at 25°C.

† All amounts shown in USD
Ordering Example: (1) 55007 Thermistor, 5000 ohms at 25°C (77°F), 2.4 mm (0.095, USD27.00