Temperature Sensors - PTC Thermistors

Image Part Number Description / PDF Quantity Rfq
TFPT0805L1501JY

TFPT0805L1501JY

Vishay / Dale

THERMISTOR PTC 1.5K OHM 5% 0805

0

B59901D130A40

B59901D130A40

TDK EPCOS

THERMISTOR PTC 100 OHM RADIAL

0

TFPT0805L1200FY

TFPT0805L1200FY

Vishay / Dale

THERMISTOR PTC 120 OHM 1% 0805

0

KTY82/120/DG/B2,21

KTY82/120/DG/B2,21

NXP Semiconductors

THERMISTOR PTC 1K OHM TO236AB

0

PR421D050S701H

PR421D050S701H

TE Connectivity Measurement Specialties

THERMISTOR PTC 70 OHM RECT

0

KTY83/110,113

KTY83/110,113

NXP Semiconductors

THERMISTOR PTC 1K OHM DO34

0

TFPT0805L1000FY

TFPT0805L1000FY

Vishay / Dale

THERMISTOR PTC 100 OHM 1% 0805

0

PRF18BD471QB1RB

PRF18BD471QB1RB

TOKO / Murata

THERMISTOR PTC 470 OHM 50% 0603

0

TFPT0805L4701FY

TFPT0805L4701FY

Vishay / Dale

THERMISTOR PTC 4.7K OHM 1% 0805

0

B59083G1120A161

B59083G1120A161

TDK EPCOS

THERMISTOR PTC 16 OHM 20% SMD

0

B59601A75B62

B59601A75B62

TDK EPCOS

THERMISTOR PTC 470 OHM 50% 0603

0

PTFT0805L2201JV

PTFT0805L2201JV

Vishay / Dale

THERMISTOR PTC 2.2K OHM 5% 0805

0

TFPT0805L1000KY

TFPT0805L1000KY

Vishay / Dale

THERMISTOR PTC 100 OHM 10% 0805

0

B59901D0070A040

B59901D0070A040

TDK EPCOS

THERMISTOR PTC 100 OHM RADIAL

0

P5010D090S401H

P5010D090S401H

TE Connectivity Measurement Specialties

THERMISTOR PTC 40 OHM COIN

0

KTY84/151,113

KTY84/151,113

NXP Semiconductors

THERMISTOR PTC 603 OHM DO34

0

TFPT0805L1001FZ

TFPT0805L1001FZ

Vishay / Dale

THERMISTOR PTC 1K OHM 1% 0805

0

KTY136

KTY136

IR (Infineon Technologies)

THERMISTOR PTC 2K OHM 3% SOT23-3

0

B59107J0130A020

B59107J0130A020

TDK EPCOS

THERMISTOR PTC 56 OHM RADIAL

0

KTY11-6

KTY11-6

IR (Infineon Technologies)

THERMISTOR PTC 2K OHM 3% TO92

0

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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