PTC Thermistor Manufacturer
PTC (positive temperature coefficient) thermistors are widely used in many industries because of their unique resistance that increases with temperature. The main functions include temperature sensing, overcurrent protection, self-recovery insurance, heating elements, etc.
Advantages of PTC Thermistors for Electronics and Electrical Products
In the electronics and electrical industry, PTC thermistors have the advantages of overcurrent protection, precise temperature sensing, high voltage resistance and high reliability. They can automatically respond to overcurrent or overheating faults, cut off the circuit through a sudden increase in resistance, and recover automatically after the fault is eliminated without replacement (such as for USB port or lithium battery protection); they can also be used as high-precision temperature sensors or compensation elements to improve circuit stability. Their high voltage resistance and anti-aging characteristics make them suitable for harsh environments, such as power modules, motor drives and other scenarios, greatly reducing maintenance costs and enhancing system safety.
Nonlinear High Sensitivity
It presents a steep resistance-temperature curve near the Curie temperature point. A small temperature change can cause a significant resistance jump, which is suitable for high-precision detection in a narrow temperature range (such as ±0.5℃ accuracy).
Fast Thermal Response
Fast Thermal Response Ceramic semiconductor materials are used, with a small thermal time constant (as low as seconds), which can track temperature fluctuations in real time and is suitable for dynamic temperature control scenarios (such as motor winding temperature monitoring).
Self-calibration Feature
Self-calibration Feature The Curie temperature is determined by the material formula firmware, with good repeatability and long-term stability without additional calibration (such as constant temperature control of medical equipment).
Wide Temperature Range Selectability
Self-calibration Feature The Curie temperature is determined by the material formula firmware, with good repeatability and long-term stability without additional calibration (such as constant temperature control of medical equipment).
PTC Thermistor Components
We have material preparation equipment, molding equipment and sintering equipment, etc., and adopt a complete quality assurance system to ensure the safety and stability of every product we produce.
MZ Series
MZ Series
MZ series thermistors are surge suppression PTC thermistors, mainly used for overcurrent protection, with high withstand voltage, fast response and self-recovery characteristics, and are widely used in circuit protection of power supplies, motors and electronic equipment.
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Special Series for Welding Machines
Special Series for Welding Machines
Special PTC thermistors for electric welding machines (usually high-power PTCs) are used to suppress startup surge current, protect welding machine circuits, and improve equipment stability and life.
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WMZ12A Series
WMZ12A Series
WMZ12A is a high-power epoxy coating PTC thermistor, mainly used for overcurrent protection, with high withstand voltage, fast response and self-recovery characteristics, suitable for power supplies, motors and industrial equipment circuit protection.
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SP Series
SP Series
SP series PTC thermistors have the characteristics of fast response, stability and reliability, and are widely used in temperature detection and control of home appliances, automotive electronics and industrial equipment.
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PTB Series
PTB Series
PTB series PTC thermistors are designed as extreme temperature sensors to sense temperature and send signals to PCB recorders to measure, control and limit temperature in various applications such as motors, industry, and new energy vehicles.
Learn MoreMZ4 PTC Thermistor Case Study
Project Overview
Customer Industry: Industrial Power Equipment Manufacturer Application Requirements: A reliable overcurrent protection component is needed to prevent the power module from being damaged by short circuit or overload. Challenges: Traditional fuses need to be replaced after they are blown, which has high maintenance costs; while ordinary PTCs have insufficient response speed or withstand voltage and cannot meet industrial-grade requirements.
Client Requirements
• Over-current protection threshold: 5A (normal operating current: 3A; must trigger quickly at 5A). • Voltage tolerance: ≥60V DC (to suit industrial power environments). • Fast response: Must enter a high-resistance state within milliseconds (<100ms) upon over-current. • Self-recovery function: Automatically resets after fault clearance to minimize downtime. • Wide temperature operation: Stable performance from -40°C to +85°C. • Long lifespan: ＞1,000 overcurrent protection cycles.
Our Solution
Recommended Product: MZ4-5A PTC Thermistor Key Parameters: • Trip current: 5A (precise protection, avoiding false triggers). • Voltage tolerance: 100V DC (exceeds customer requirements). • Maximum steady-state current: 3A (matches equipment's rated current). • Response time: <50ms (significantly faster than traditional fuses). • Encapsulation: Epoxy/ceramic housing, shockproof and moisture-resistant.
Solution Advantages
✔ Millisecond-level protection: Far faster than fuses (which take seconds to blow), reducing short-circuit damage risks. ✔ Maintenance-free: Automatically recovers after fault clearance, eliminating manual replacement. ✔ Industrial-grade reliability: Wide temperature range, shock/vibration resistance, suitable for harsh environments. ✔ Space-saving: Compact design for high-density layouts.
Provide High Quality PTC Thermistors for Electronics and Electrical Industry
We provide a full range of services from samples to mass production to meet the needs of different electronic and electrical equipment and application scenarios. Our technical team works closely with customers to ensure that each product meets the strict standards and specific needs of the electronics and electrical industry.
Pain point 1: Insufficient response speed leads to protection delay
Problem: When some PTCs are overcurrent or over-temperature, the resistance rises slowly (such as seconds), and cannot effectively protect sensitive devices Solution: • Use low thermal capacity and high sensitivity PTC to shorten the response time to milliseconds. • In the key circuit, connect fast fuses in parallel to form double protection (PTC is responsible for recoverable protection, and fuses are responsible for extreme situations).
Pain point 2: Residual resistance after self-recovery affects system restart
Problem: After the PTC is triggered, it cools and resets, but the resistance may not be fully restored to the initial value, resulting in the inability of the device to restart normally. Solution: • Choose a low residual resistance (Rmin) model. • Design an automatic power-off delay circuit to ensure that the PTC is fully cooled before powering on.
Pain point 3: False triggering or failure in high temperature environment
Problem: High temperature environment (such as car engine compartment) may cause PTC to operate prematurely or performance degradation. Solution: • Select high temperature PTC (such as ceramic base, operating temperature can reach above 125°C). • Add heat dissipation design (such as metal bracket heat conduction) to reduce the temperature rise of PTC body.
Pain point 4: Performance degradation after multiple cycles
Problem: Frequent overcurrent/over-temperature triggering will cause PTC material aging, resistance drift or action threshold change. Solution: • Select high cycle life model (such as automotive grade PTC with ≥100,000 cycles). • Regularly test PTC resistance and include it in the equipment preventive maintenance plan.
Pain point 5: Severe heat generation when high current is applied
Problem: In high current scenarios (such as motor drive), the heat generated by PTC's own power consumption may aggravate the temperature rise. Solution: • Use low resistance PTC (such as R25<1Ω) to reduce steady-state power consumption. • Design voltage divider and current divider circuit to reduce the current passing through PTC.
Wide Applications of PTC Thermistors in Electronics and Electrical Industries
According to the requirements of different electronic and electrical equipment, we can provide a variety of PTC thermistor options, such as ceramic PTC, polymer PTC, SMD PTC, etc. In addition, we can also combine PTC thermistors with varistors and other materials to provide composite material solutions to meet more complex equipment needs.
PTC Thermistor Production Process
The production of PTC (positive temperature coefficient) thermistors is a complex process involving material science, precision machining and rigorous testing. The following is a complete production process, covering all aspects from raw materials to finished products:
1. Raw material preparation
Substrate selection: Ceramic PTC: mainly high-purity barium titanate (BaTiO₃), doped with rare earth elements (such as Y, Nb) to adjust the Curie temperature (Tc) Polymer PTC: polyethylene (PE) or polyvinylidene fluoride (PVDF) mixed with conductive fillers (such as carbon black). Additives: Sintering aids (such as SiO₂, Al₂O₃) improve ceramic density. Dispersants ensure material uniformity.
2. Formula and mixing
Ratio calculation: adjust the doping ratio according to the target resistivity and Tc (such as 0.3% Y30 doping in BaTiO₃). Mixing process: Ball milling: wet ball milling (alcohol medium) for 4-12 hours, particle size controlled at 0.5-1μm. Polymer mixing: internal mixer heated to 180℃for melt blending.
3. Molding process
(1) Ceramic PTC molding Dry pressing: Pressure: 50-200MPa, made into discs or square blocks (such asφ10mm×2mm). Density control: ≥5.8g/cm³to reduce sintering shrinkage. Casting (film PTC): Slurry coating thickness 50-200μm, cut after drying. (2) Polymer PTC molding Extrusion molding: melt extrusion into film (0.1-0.5mm thick) or wire. Injection molding: complex shape components (such as SMD package base).
4. Sintering (key step of ceramic PTC)
Debinding stage: 300-500℃ to remove the binder (heating rate 1-3℃/min). High temperature sintering: Temperature: 1200-1400℃ (BaTiO₃based), precisely controlled ±5℃. Atmosphere: Oxidizing atmosphere (air or O₂) to prevent Ti4⁺reduction. Hot holding time: 2-4 hours to form semiconducting grain boundaries. Cooling control: Slow cooling (2-5℃/min) to avoid internal stress cracks.
5. Electrode preparation
Ceramic PTC electrode: Screen printing: Ag/Pd slurry (ratio 7:3), sintered at 850℃ after printing. Sputtering coating: Al/Ni thin film (for miniaturized devices). Polymer PTC electrode: Vacuum evaporation of Ni or Cu (thickness 1-5μm). Thickening by electroplating (up to 20μm) reduces contact resistance.
6. Performance adjustment
Resistance adjustment: Laser fine-tuning: accuracy ±1% (such as adjusting the resistance at 25℃from 10Ω±10% to 10Ω±1%). Chemical etching: Control electrode contact area. Heat treatment: 500-800℃ annealing stabilizes grain boundary properties.
7. Packaging and protection
Ceramic PTC packaging: Epoxy resin potting (temperature resistance 150℃). Metal shell (stainless steel shell is used for automotive-grade products). Polymer PTC packaging: Heat shrink tubing (voltage resistance 600V). SMD patch packaging (such as 0805, 1206).
8. Testing and sorting
Key test items:
| Parameters | Test Method | Standard Examples |
|---|---|---|
| Room temperature resistance (R25) | Four-wire measurement (1mA DC) | IEC 60738 |
| Curie temperature (Tc) | DSC analysis or R-T curve inflection point | ±2°C tolerance |
| Withstand voltage test | 2 times rated voltage for 60 seconds | UL1434 |
| Cycle life | 1000 on-off cycles (5A → cut off → cool down) | Resistance change rate ≤15% |
Automatic sorting: Optical inspection of appearance defects. Resistance/temperature characteristics classification (such as ±5%, ±10% accuracy groups).
Key control points of the production process
Why Choose Tianrui
As a professional PTC thermistor manufacturer, we provide customers with high-reliability solutions with the following core advantages:
Material and process advantages We have independently developed ceramic formulas and polymer composite materials technology. Through precise doping and advanced sintering processes, we can achieve high-precision control of Curie temperature (Tc) ±2°C, ensuring the stability and consistency of products in scenarios such as overcurrent protection and temperature sensing.
High performance and high reliability
The products cover a wide temperature range of -40°C to 150°C, withstand voltage up to 1000V DC, and have passed international certifications such as AEC-Q200, UL/TUV. Strict life testing (>100,000 cycles) and full-process quality control meet the requirements of harsh environments such as automobiles and industries.
Fast customization and flexible service
Supports customization of parameters such as Tc, R25, and packaging, provides samples within 7-15 days, and can provide circuit design support for application scenarios (such as lithium battery protection and motor drive) to help customers optimize system safety.
Large-scale production capacity
The fully automated production line ensures the consistency of large-scale delivery, combined with a complete traceability system, to ensure full control from raw materials to finished products, providing customers with cost-effective and stable supply. We are committed to becoming your trusted PTC thermistor partner through technological innovation and customer-oriented services!
