Temperature Sensors - PTC Thermistors

Image Part Number Description / PDF Quantity Rfq
B59052D1120A40

B59052D1120A40

TDK EPCOS

PTC THERMISTOR D 052-A 120-A 40

798

B59544A0120A020

B59544A0120A020

TDK EPCOS

THERMISTOR PTC 20 OHM 20% DISC

0

B59721A0090A062

B59721A0090A062

TDK EPCOS

THERMISTOR PTC 680 OHM 50% 0805

717

B59100M1130A070

B59100M1130A070

TDK EPCOS

THERMISTOR PTC 100 OHM

486

B59053A0220A010

B59053A0220A010

TDK EPCOS

THERMISTOR PTC 6K OHM 35% DISC

0

B59841C0135A070

B59841C0135A070

TDK EPCOS

THERMISTOR PTC 6 OHM 25% DISC

1992

B59100C0100A070

B59100C0100A070

TDK EPCOS

THERMISTOR PTC 100 OHM RADIAL

1329

B59100M1120A070

B59100M1120A070

TDK EPCOS

THERMISTOR PTC 100 OHM

691

B59100C0010A070

B59100C0010A070

TDK EPCOS

THERMISTOR PTC 5K OHM DISC

0

B59524A0135A020

B59524A0135A020

TDK EPCOS

THERMISTOR PTC 22 OHM 20% DISC

0

B59100M1110A070

B59100M1110A070

TDK EPCOS

THERMISTOR PTC 100 OHM

2660

B59601A0125B062

B59601A0125B062

TDK EPCOS

THERMISTOR PTC 470 OHM 50% 0603

0

B59501A0135A020

B59501A0135A020

TDK EPCOS

THERMISTOR PTC 33 OHM 20% DISC

2232

B59052D1110A40

B59052D1110A40

TDK EPCOS

PTC THERMISTOR D 052-A 110-A 40

798

B59060A0160A010

B59060A0160A010

TDK EPCOS

THERMISTOR PTC 9 OHM 30% DISC

0

B59339A1501P020

B59339A1501P020

TDK EPCOS

THERMISTOR PTC 500 OHM 25% RAD

220

B59008C0150A040

B59008C0150A040

TDK EPCOS

THERMISTOR PTC 250 OHM RADIAL

990

B59875C0120A570

B59875C0120A570

TDK EPCOS

THERMISTOR PTC 65 OHM 25% RADIAL

357

B59300M1180A070

B59300M1180A070

TDK EPCOS

THERMISTOR PTC 300 OHM RADIAL

0

B59100M1140A070

B59100M1140A070

TDK EPCOS

THERMISTOR PTC 100 OHM

200

Temperature Sensors - PTC Thermistors

1. Overview

Positive Temperature Coefficient (PTC) thermistors are resistors with a positive temperature coefficient, meaning their resistance increases significantly with temperature rise. Unlike NTC thermistors, PTC devices exhibit a sharp resistance transition at a critical temperature (Curie point). They are widely used in overtemperature protection, self-regulating heating elements, and temperature sensing applications. Their inherent safety features and reliability make them critical components in modern electronics, automotive systems, and industrial equipment.

2. Main Types and Functional Classification

TypeFunctional CharacteristicsApplication Examples
Ceramic PTC ThermistorsHigh Curie temperature, abrupt resistance change, durableOverheat protection in motors, heaters, and power supplies
Polymer PTC ThermistorsLower switching temperature, resettable fuse functionalityUSB port protection, battery management systems
Switching PTCDigital on/off behavior at threshold temperatureThermal cutoff for appliances, HVAC systems
Linear PTCProportional resistance-temperature responsePrecision temperature measurement in industrial controllers

3. Structure and Composition

PTC thermistors typically consist of polycrystalline ceramic semiconductor materials (e.g., BaTiO3 doped with rare earth elements) with embedded silver or platinum electrodes. The core structure includes: - Semiconductor ceramic body with tailored Curie temperature - Metal electrodes for electrical connection - Protective epoxy or glass coating - Lead wires (axial/radial) or SMD terminations The PTC effect arises from the material's phase transition at Curie temperature, causing resistance spikes due to crystal lattice changes.

4. Key Technical Specifications

ParameterDescriptionImportance
R25 (Resistance at 25 C)Baseline resistance valueDetermines circuit compatibility
Tswitch (Switching Temperature)Critical temperature for resistance jumpApplication-specific threshold setting
Rmin/Rmax RatioResistance range spanIndicates sensitivity and switching capability
Dissipation Factor (mW/ C)Power dissipation per temperature unitAffects thermal response speed
Response Time (ms)Time to reach 90% resistance changeCritical for real-time protection systems

5. Application Fields

Major application sectors include: - Consumer Electronics: Smartphones (battery protection), 3D printers (hotend monitoring) - Automotive: EV battery thermal management, seat heater control - Industrial: Motor overload protection, pipeline freeze detection - Renewable Energy: Solar charge controllers, wind turbine gear monitoring - Medical: Patient warming systems, diagnostic equipment thermal regulation

6. Leading Manufacturers and Products

ManufacturerKey ProductsFeatures
Vishay BeyschlagK2500-FinderAutomotive-grade PTC with 50-150 C range
TE ConnectivityPS224-202UL-certified resettable fuse for power supplies
Murata ElectronicsPXU11S150R0Miniature SMD PTC for IoT devices
EPCOS (TDK)B59904C0150A070High-current PTC for industrial motor protection

7. Selection Guidelines

Key selection criteria: - Required switching temperature vs operating temperature range - Resistance tolerance and stability over lifespan - Package type (through-hole, SMD, bolt-on) - Voltage/current ratings with safety margin - Compliance with standards (UL, RoHS, AEC-Q200 for automotive) - Environmental resistance (humidity, vibration, chemical exposure)

8. Industry Trends

Emerging trends include: - Development of nano-ceramic materials for faster response times (<10ms) - Integration with MEMS technology for IoT sensor nodes - Higher temperature stability beyond 200 C for e-mobility applications - Miniaturization to 0402 SMD package sizes - AI-based predictive thermal management systems using PTC arrays - Increased adoption in hydrogen fuel cell thermal monitoring systems

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