What does the B value mean in a thermistor?

The B value (or Beta value) is a material constant that describes the sensitivity of an NTC thermistor over a temperature range, expressed in Kelvin (K). A higher B value indicates greater sensitivity. For example, a B value of 3950K means the thermistor is highly sensitive across its operating range. The B value is used to calculate resistance at any temperature using the Steinhart-Hart equation.

What resistance value should I choose for my NTC thermistor?

The most common values are 10K ohm (at 25°C), which is widely used in TEC controllers, laser systems, and general temperature sensing. 100K ohm thermistors are preferred for wider temperature ranges and lower self-heating. 5K and 50K options offer alternatives depending on your circuit impedance requirements. For TEC controller applications, 10K is the standard recommendation.

What is the temperature range of Analog Technologies NTC thermistors?

Our glass-encapsulated NTC thermistors cover a wide operating range. Most models operate from -40°C to +250°C, with select models covering -55°C to +250°C and high-temperature versions rated up to +300°C. The operating range depends on the specific model and encapsulation style.

Can I get custom thermistor assemblies?

Yes. Analog Technologies offers fully customized thermistor assemblies including custom wire lengths (specify in mm), custom connector types, custom housing materials (stainless steel, metal cap, etc.), and custom resistance values. Please contact our sales team at sales@analogti.com to discuss your specific requirements.

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Home > Products > Thermistors

NTC Thermistors and Thermistor Assemblies

Q: What is the difference between NTC and PTC thermistors?

NTC (Negative Temperature Coefficient) thermistors decrease in resistance as temperature rises, making them ideal for temperature sensing and measurement. PTC (Positive Temperature Coefficient) thermistors increase in resistance with temperature, typically used for overcurrent protection. NTC thermistors offer higher sensitivity and are the preferred choice for precision temperature measurement applications.

Q: Why choose glass encapsulated thermistors over epoxy encapsulated?

Glass encapsulated thermistors offer nearly zero long-term drift compared to epoxy types which can exhibit higher drift over years of use. They also support a wider temperature range (up to 300°C), smaller bead sizes (from 0.8mm diameter), and faster thermal response times. For precision applications requiring long-term stability, glass encapsulation is strongly preferred.

NTC Thermistors Selection Guide

NTC (Negative Temperature Coefficient) Thermistors are high-sensitivity temperature sensors widely used in industrial, medical, and consumer applications. Compared to RTDs, thermocouples, and temperature ICs, NTC thermistors deliver superior sensitivity, low noise, and minimal peripheral circuitry at very low cost — making them the preferred choice for precision temperature sensing in compact systems.

All of our thermistors use glass encapsulation, which provides near-zero long-term drift, a wider operating temperature range (up to 300°C), and smaller bead sizes versus conventional epoxy encapsulated types. These properties make them ideal for use with our TEC controllers and TEC modules to build high-stability, low-drift temperature regulation systems.

±0.05°C

Precision @ 25°C

0.8mm

Min. Bead Diameter

-55°C ~ +300°C

Operating Temp. Range

~$0.8

From @ 500pcs

≈0 Drift

Glass Encapsulation

Glass-encapsulated thermistors are available in two lead styles: axial (leads from opposite ends) and radial (leads from the same side). We also offer lug-mount versions with a metal ring for easy attachment to thermal conductive surfaces. Bare radial beads (Φ0.8–1.3mm) are commonly used for sensing laser diode chip temperatures; axial styles suit battery packs and consumer electronics.

For assistance selecting the right thermistor or assembly, please contact us — we're happy to help with custom requirements.

How it works — See our videos
RoHS Certificate of Compliance for Thermistors
REACH Certificate of Compliance for Thermistors

NTC Thermistor vs. RTD vs. Thermocouple: Which to Choose?

Parameter	NTC Thermistor	RTD (PT100/PT1000)	Thermocouple
Sensitivity	⭐⭐⭐⭐⭐ Very High	⭐⭐⭐ Moderate	⭐⭐ Low
Accuracy	±0.05°C (precision models)	±0.1°C typical	±1–2°C typical
Temperature Range	-55°C to +300°C	-200°C to +850°C	-200°C to +1700°C
Response Time	Fast (small bead: <1s)	Moderate	Moderate to Slow
Cost	⭐⭐⭐⭐⭐ Very Low	⭐⭐⭐ Moderate	⭐⭐⭐ Moderate
Linearity	Non-linear (needs correction)	Near-linear	Non-linear
Best For	TEC control, laser diodes, medical, battery, precision sensing	Industrial process control	High-temperature industrial

Typical Applications by Industry

Industry / Application	Recommended Thermistor Type	Key Requirement
Laser Diode Temperature Control	10K, Φ0.8mm bare bead (e.g., ATH10KR8B)	Small size, fast response, used with TEC controllers
Medical Devices	Precision ±0.05°C models, glass encapsulated	Long-term stability, near-zero drift
Battery Pack / BMS	10K axial with leads (e.g., ATH10K1R25)	Wide temp range, cost-effective
Industrial HVAC	Thermistor assemblies with metal housing	Durability, moisture resistance
Optical / Photonics	Φ0.8mm–1.3mm bare bead, high B-value	Miniature size, non-intrusive mounting
Consumer Electronics	Epoxy or glass radial lead thermistors	Low cost, high volume availability

Glass Encapsulated NTC Thermistors

This series thermistor is encapsulated by glass. The glass ensures long term stability. Compared to conventional epoxy encapsulated thermistors, they feature a smaller size, quicker response time, better long term stability, and wider temperature range. This kind thermistor is sealed between the head and sensing tip allowing it to work up to 250°C temperature.

Φ(mm)	Part Number	Nominal Resistance @ 25°C	Thermistor Diameter	Operating Temp Range	Dissipation Factor	B Value @ 25°C /50°C	Maximum Power @ 25°C	Note	Stock Status
0.8	ATH5KR8B3950K	5K ± 1%	0.8 ± 0.15mm	-40°C to +250°C	1.2mW/°C	3950K ± 1%	50mW	Bare leads	0
	ATH10KR8B	10K ± 1%	0.8 ± 0.1mm	-55°C to +250°C	0.4mW/K	*	18mW	Bare leads	0
	ATH10KR8BT65	10K ± 1%	0.8 ± 0.1mm	-55°C to +250°C	0.4mW/K	*	18mW	With tubings, non-sealed	120
	ATH10KR8BT65S	10K ± 1%	0.8 ± 0.1mm	-55°C to +250°C	0.4mW/K	*	18mW	With tubings, sealed	129
	ATH10KR8B3404K	10K ± 1%	0.8 ± 0.15mm	-40°C to +200°C	1.2mW/°C	3404K ± 1%	*	Bare leads	0
	ATH10KR8B3404KT65	10K ± 1%	0.8 ± 0.15mm	-40°C to +200°C	1.2mW/°C	3404K ± 1%	*	With tubings, non-sealed	0
	ATH10KR8B3404KT65S	10K ± 1%	0.8 ± 0.15mm	-40°C to +200°C	1.2mW/°C	3404K ± 1%	*	With tubings, sealed	0
	ATH10KR8B3950K0.5%	10K ± 0.5%	0.8 ± 0.15mm	-40°C to +250°C	1.2mW/°C	3950K ± 1%	*	Bare leads	0
	ATH50KR8B3950K	50K ± 1%	0.8 ± 0.1mm	-40°C to +300°C	0.6mW/°C	3950K ± 1%	50mW	Bare leads	0
	ATH50KR8B3950K0.5%	50K ± 0.5%	0.8 ± 0.1mm	-40°C to +300°C	0.6mW/°C	3950K ± 1%	50mW	Bare leads	360
	ATH100KR8	100K ± 1%	0.8 ± 0.1mm	-55°C to +250°C	0.4mW/K	4066K ± 1%	18mW	Bare leads	127
	ATH100KR8T63	100K ± 1%	0.8 ± 0.1mm	-55°C to +250°C	0.4mW/K	4066K ± 1%	18mW	With tubings, non-sealed	14
	ATH100KR8T63S	100K ± 1%	0.8 ± 0.1mm	-55°C to +250°C	0.4mW/K	4066K ± 1%	18mW	With tubings, sealed	0
	ATH100KR8B3950K	100K ± 1%	0.8 ± 0.2mm	-40°C to +300°C	0.6mW/°C	3950K ± 1%	50mW	Bare leads	0
	ATH100KR8B3950K0.5%	100K ± 0.5%	0.8 ± 0.2mm	-40°C to +300°C	0.6mW/°C	3950K ± 1%	50mW	Bare leads	400
	ATH230KR8B4177K	230K ± 1%	0.8 ± 0.2mm	-40°C to +300°C	0.6mW/°C	4177K ± 1%	50mW	Bare leads	0
1	ATH10K1R0	10K ± 1%	1.0 ± 0.1mm	-55°C to +250°C	0.5mW/K	3478K ± 1%	18mW	Epoxy encapsulated thermistor	1825
1.25	ATH10K1R25	10K ± 1%	1.25 ± 0.03mm	-40°C to +270°C	1.0mW/°C	3950K ± 1%	*	Bare leads	55
	ATH10K1R25T70	10K ± 1%	1.25 ± 0.03mm	-40°C to +270°C	1.0mW/°C	3950K ± 1%	*	Leads with tubings, non-sealed	100
	ATH10K1R25T70S	10K ± 1%	1.25 ± 0.03mm	-40°C to +270°C	1.0mW/°C	3950K ± 1%	*	Leads with tubings, sealed	203
	ATH100K1R25	100k ± 1%	1.25 ± 0.2mm	-40°C to +270°C	0.9mW/°C	3950K ± 1%	*	Bare leads	945
	ATH100K1R25T70	100k ± 1%	1.25 ± 0.2mm	-40°C to +270°C	0.9mW/°C	3950K ± 1%	*	Leads with tubings, non-sealed	0
	ATH100K1R25T70S	100k ± 1%	1.25 ± 0.2mm	-40°C to +270°C	0.9mW/°C	3950K ± 1%	*	Leads with tubings, sealed	10
1.3	ATH5K1R3B3950K	5K ± 1%	1.3 ± 0.2mm	-40°C to +250°C	0.9mW/°C	3950K ± 1%	35mW	Bare leads	0
	ATH5K1R3B3950KT65	5K ± 1%	1.3 ± 0.2mm	-40°C to +250°C	0.9mW/°C	3950K ± 1%	35mW	Leads with tubings, non-sealed	0
	ATH5K1R3B3950KT65S	5K ± 1%	1.3 ± 0.2mm	-40°C to +250°C	0.9mW/°C	3950K ± 1%	35mW	Leads with tubings, sealed	0
	ATH10K1R3B3950K	10K ± 1%	1.3 ± 0.2mm	-40°C to +250°C	0.9mW/°C	3950K ± 1%	35mW	Bare leads	0
	ATH10K1R3B3950KT65	10K ± 1%	1.3 ± 0.2mm	-40°C to +250°C	0.9mW/°C	3950K ± 1%	35mW	Leads with tubings, non-sealed	0
	ATH10K1R3B3950KT65S	10K ± 1%	1.3 ± 0.2mm	-40°C to +250°C	0.9mW/°C	3950K ± 1%	35mW	Leads with tubings, sealed	0
	ATH10K1R3B3950K0.5%	10K ± 0.5%	1.3 ± 0.2mm	-40°C to +250°C	0.9mW/°C	3950K ± 1%	35mW	Bare leads	0
	ATH10K1R3B3950K0.5%T65	10K ± 0.5%	1.3 ± 0.2mm	-40°C to +250°C	0.9mW/°C	3950K ± 1%	35mW	Leads with tubings, non-sealed	0
	ATH10K1R3B3950K0.5%T65S	10K ± 0.5%	1.3 ± 0.2mm	-40°C to +250°C	0.9mW/°C	3950K ± 1%	35mW	Leads with tubings, sealed	0
	ATH20K1R3B3950K	20K ± 1%	1.3 ± 0.2mm	-40°C to +250°C	1.4mW/°C	3950K ± 1%	35mW	Bare leads	0
	ATH30K1R3B3950K	30K ± 1%	1.3 ± 0.2mm	-40°C to +250°C	1.4mW/°C	3950K ± 1%	35mW	Bare leads	805
	ATH50K1R3B3950K0.5%	50K ± 0.5%	1.3 ± 0.2mm	-55°C to +250°C	0.9mW/°C	3950K ± 1%	35mW	Bare leads	0
	ATH100K1R3B3950K0.5%	100K ± 0.5%	1.3 ± 0.2mm	-40°C to +250°C	0.9mW/°C	3950K ± 1%	35mW	Bare leads	0
	ATH100K1R3B3950K	100K ± 1%	1.3 ± 0.2mm	-40°C to +300°C	0.4mW/°C	3950K ± 1%	50mW	Bare leads	0
1.8	ATH5K1R8B3950K	5K± 1%	1.8 ± 0.2mm	-55°C to +250°C	2mW/°C	3950K ± 1%	50mW	Axial leaded	150
	ATH10K1R8B3950K	10K± 1%	1.8 ± 0.2mm	-55°C to +250°C	2mW/°C	3950K ± 1%	50mW	Axial leaded	200
	ATH20K1R8B3950K	20K± 1%	1.8 ± 0.2mm	-55°C to +250°C	2mW/°C	3950K ± 1%	50mW	Axial leaded	200
	ATH30K1R8B3950K	30K± 1%	1.8 ± 0.2mm	-55°C to +250°C	2mW/°C	3950K ± 1%	50mW	Axial leaded	200
	ATH50K1R8B3950K	50K± 1%	1.8 ± 0.2mm	-55°C to +250°C	2mW/°C	3950K ± 1%	50mW	Axial leaded	200
	ATH100K1R8B3950K	100K± 1%	1.8 ± 0.2mm	-55°C to +250°C	2mW/°C	3950K ± 1%	50mW	Axial leaded	200
0.55	ATH10KR55B3950K	10K ± 1%	0.55 ± 0.2mm	-30°C to +300°C	0.25mW/°C	3950K ± 1%	*	Bare leads	0

Φ(mm)	Part Number	Datasheet	Buy Now
0.8	ATH10KR8BT65
	ATH10KR8BT65S
	ATH50KR8B3950K
	ATH50KR8B3950K0.5%
	ATH100KR8
	ATH100KR8T63
	ATH100KR8T63S
	ATH100KR8B3950K
	ATH100KR8B3950K0.5%
	ATH230KR8B4177K
1	ATH10K1R0
1.25	ATH10K1R25
	ATH10K1R25T70
	ATH10K1R25T70S
	ATH100K1R25
	ATH100K1R25T70
	ATH100K1R25T70S
1.3	ATH5K1R3B3950K
	ATH10K1R3B3950K0.5%
	ATH20K1R3B3950K
	ATH30K1R3B3950K
	ATH50K1R3B3950K0.5%
	ATH100K1R3B3950K0.5%
	ATH100K1R3B3950K
1.8	ATH5K1R8B3950K
	ATH10K1R8B3950K
	ATH20K1R8B3950K
	ATH30K1R8B3950K
	ATH50K1R8B3950K
	ATH100K1R8B3950K

Thermistor Assemblies

Ring Lug

This series thermistor is a thermistor assembly with a glass encapsulated thermistor packaged in an extra compact ring lug. Compared to conventional assemblies containing epoxy encapsulated thermistors, this series thermistor presents higher long term stability, higher reliability and wider temperature range. In addition, it is a small size and has a short response time.
This series thermistor can be used to measure the temperature of laser diodes, optical components, etc., with high accuracy and long-term stability.

	Part Number	Nominal Resistance @ 25°C	Lead Diameter	Operating Temp Range	Dissipation Factor	B Value @ 25°C /50°C	Note	Stock Status
10k	ATH10KB3404KL2A	10K ± 1%	0.15mm	-40°C to +200°C	1.2mW/°C	3404K ± 1%	Bare leads	22
	ATH10KB3404KL2AT65	10K ± 1%	0.15mm	-40°C to +200°C	1.2mW/°C	3404K ± 1%	With tubings, non-sealed	52
	ATH10KB3404KL2AT65S	10K ± 1%	0.15mm	-40°C to +200°C	1.2mW/°C	3404K ± 1%	With tubings, sealed	15
	ATH10KBL2A	10K ± 1%	0.15mm	-55°C to +250°C	*	3492K ± 1%	Bare leads	109
	ATH10KBL2AT65	10K ± 1%	0.15mm	-55°C to +250°C	*	3492K ± 1%	With tubings, non-sealed	88
	ATH10KBL2AT65S	10K ± 1%	0.15mm	-55°C to +250°C	*	3492K ± 1%	With tubings, sealed	266
	ATH10KL2B	10K ± 1%	0.2mm	-40°C to +270°C	*	3950K ± 1%	Bare leads	37
	ATH10KL2BT70	10K ± 1%	0.2mm	-40°C to +270°C	*	3950K ± 1%	With tubings, non-sealed	37
	ATH10KL2BT70S	10K ± 1%	0.2mm	-40°C to +270°C	*	3950K ± 1%	With tubings, sealed	18
	ATH10KL2C	10K ± 1%	0.2mm	-40°C to +270°C	*	3950K ± 1%	Bare leads	1
	ATH10KL2CT70	10K ± 1%	0.2mm	-40°C to +270°C	*	3950K ± 1%	With tubings, non-sealed	44
	ATH10KL2CT70S	10K ± 1%	0.2mm	-40°C to +270°C	*	3950K ± 1%	With tubings, sealed	100
	ATH10KL2D	10k ± 1%	0.2mm	-40°C to +270°C	*	3950K ± 1%	Bare leads	0
	ATH10KL2DT70	10k ± 1%	0.2mm	-40°C to +270°C	*	3950K ± 1%	With tubings, non-sealed	0
	ATH10KL2DT70S	10k ± 1%	0.2mm	-40°C to +270°C	*	3950K ± 1%	With tubings, sealed	0
100k	ATH100KL2A	100K ± 1%	0.15mm	-55°C to +250°C	*	4066K ± 1%	Bare leads	21
	ATH100KL2AT63	100K ± 1%	0.15mm	-55°C to +250°C	*	4066K ± 1%	With tubings, non-sealed	21
	ATH100KL2AT63S	100K ± 1%	0.15mm	-55°C to +250°C	*	4066K ± 1%	With tubings, sealed	9
	ATH100KL2B	100K ± 1%	0.2mm	-40°C to +270°C	*	3950K ± 1%	Bare leads	23
	ATH100KL2BT70	100K ± 1%	0.2mm	-40°C to +270°C	*	3950K ± 1%	With tubings, non-sealed	23
	ATH100KL2BT70S	100K ± 1%	0.2mm	-40°C to +270°C	*	3950K ± 1%	With tubings, sealed	23
	ATH100KL2C	100K ± 1%	0.2mm	-40°C to +270°C	*	3950K ± 1%	Bare leads	110
	ATH100KL2CT70	100K ± 1%	0.2mm	-40°C to +270°C	*	3950K ± 1%	With tubings, non-sealed	0
	ATH100KL2CT70S	100K ± 1%	0.2mm	-40°C to +270°C	*	3950K ± 1%	With tubings, sealed	0

Part Number	Datasheet With Pricelist	Buy Now
ATH10KB3404KL2A
ATH10KB3404KL2AT65
ATH10KB3404KL2AT65S
ATH10KL2B
ATH10KL2BT70
ATH10KL2BT70S
ATH10KL2C
ATH10KL2CT70
ATH10KL2CT70S
ATH10KL2D
ATH10KL2DT70
ATH10KL2DT70S
ATH100KL2A
ATH100KL2AT63
ATH100KL2AT63S
ATH100KL2B
ATH100KL2C
ATH100KL2CT70
ATH100KL2CT70S

Hex Nut

This series thermistor is a thermistor assembly with threaded hex nut. It has bear leads coated with copper. The thermistor assembly presents long term stability, high reliability and wide temperature range, compact size and short response time. It can be used for temperature sensing and detection, transformers, and air sensors, etc.

Part Number	Nominal Resistance @ 25°C	Thermistor Diameter	Stock Status
ATH10KHN4	10K ± 1%	3990K ± 1%	27
ATH10KHN6	10K ± 1%	3990K ± 1%	5
ATH10KHN10	10K ± 1%	3990K ± 1%	10
ATH10KHN12	10K ± 1%	3990K ± 1%	10

Part Number	Datasheet With Pricelist	Buy Now
ATH10KHN4
ATH10KHN6
ATH10KHN10
ATH10KHN12

Other Types

This series thermistor assembly is housed by a metal cap. The thermistor inside has glass encapsulation to ensure long time operation, wide temperature range, and no parameter drift of either short time or long term. The cap is made of metal, making them long time lasting even under harsh environment, such as acid, moisture, etc. The output terminals use a pair of heavy duty PVC insulated wires of 26 AWG. The length of the wires can be specified. The cap can be customized according to customers need.

Part Number	Nominal Resistance @ 25°C	B Value @ 25°C /85°C	Datasheet	Stock Status	Buy Now
ATSC230K-100	231.5±16.9K	4170K		50

Part Number	Datasheet With Pricelist	Buy Now
ATSC230K-100

Frequently Asked Questions — NTC Thermistors

What is the difference between NTC and PTC thermistors?

NTC (Negative Temperature Coefficient) thermistors decrease in resistance as temperature rises, making them ideal for temperature sensing and measurement. PTC (Positive Temperature Coefficient) thermistors increase in resistance with temperature, and are typically used for overcurrent protection or self-regulating heating elements. For precision temperature measurement in industrial and medical applications, NTC thermistors are the preferred choice due to their high sensitivity and fast response times.

What does the B value (Beta value) mean in a thermistor?

The B value (or Beta value) is a material constant expressed in Kelvin (K) that describes the sensitivity of an NTC thermistor across a temperature range. A higher B value indicates greater sensitivity. For example, our thermistors commonly feature B values of 3950K or 4066K. The B value is used alongside the Steinhart-Hart equation to accurately calculate resistance at any temperature within the operating range. Common B value ranges for our products are 3404K to 4177K.

Why choose glass encapsulated thermistors over epoxy encapsulated?

Glass encapsulated thermistors offer nearly zero long-term resistance drift compared to epoxy encapsulated models, which can drift measurably over months and years of operation. Glass encapsulation also enables a wider operating temperature range (up to 300°C vs. typically 150°C for epoxy), smaller bead sizes (from 0.8mm diameter), and better resistance to moisture and chemical exposure. For all precision applications, we exclusively use glass encapsulation in our thermistors and thermistor assemblies.

What resistance value should I choose — 5K, 10K, or 100K?

The most commonly used value is 10K ohm (at 25°C), which is the standard for TEC controllers, laser diode modules, and general-purpose temperature sensing. 100K thermistors are preferred for applications requiring very low self-heating or where higher impedance is needed, such as battery monitoring at low temperatures. 5K thermistors are sometimes used in lower-impedance circuits. For compatibility with our TEC controllers, 10K is the standard recommendation.

What is the operating temperature range of your thermistors?

Our glass-encapsulated NTC thermistors cover a wide operating range depending on the model. Standard models operate from -40°C to +250°C. High-sensitivity small-bead models (Φ0.8mm) cover -55°C to +250°C. High-temperature models extend coverage up to +300°C. Thermistor assemblies with metal cap housings maintain performance across the full -40°C to +250°C range even in harsh environments with moisture or chemical exposure.

Can I order custom thermistor assemblies with specific wire lengths or connectors?

Yes, Analog Technologies offers fully customized thermistor assemblies. You can specify custom wire lengths (in mm), wire gauge (standard is 26 AWG PVC insulated), housing material (stainless steel, metal cap, etc.), connector type, and resistance value. Minimum order quantities apply for custom designs. Please contact our sales team at sales@analogti.com or call (408) 748-9100 to discuss your requirements.