The PTC thermistor is mounted in thermal contact with equipment requiring protection and connected to a comparator circuit bridge arm. At normal temperatures, the PTC thermistor resistance (Rp) remains lower than the reference resistance (Rs), keeping the comparator output voltage low. During over-temperature conditions, the thermistor rapidly heats to its trigger temperature (Tn), causing resistance to increase significantly above Rs. This triggers the comparator output to switch high, activating alarms, relays, or power shutdown circuits.

• Industrial electronics temperature limit measurement
• Power supplies and switch mode power supplies
• Home appliances: dishwashers, washing machines, ironing machines, electric cookers
• Electronic data processing and communications engineering (DC/DC converters)
• Motor windings overheating protection
• Automotive electronics
• Semiconductor heatsinks, enclosure panels, temperature-limited transistors
• Lighting applications

• Two construction types: radial leaded epoxy resin coated and metal tag lug form
• Custom screw type metal cases available upon request
• Protection temperature range: 60°C to 130°C (60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C)
• Quick response time
• Long-term stability
• Compact dimensions for easy installation
• No reset required after protection activation

PTC Thermistor Limit Temperature Sensors feature ceramic PTC thermistor disks in radial resin bead or metal lug construction, designed for precise temperature sensing and protection applications. These devices switch at specific temperatures, making them ideal for monitoring temperature limits and activating cooling systems when thresholds are reached.

Utilizing the characteristic sharp resistance increase above Curie temperature, PTC thermistors trigger protective circuits to activate or interrupt loops during abnormal temperature rises, achieving reliable thermal protection.

Compared to thermostats, PTC thermistors offer more precise switch temperature specification, smaller size, easier electronic circuit integration, and lower cost. They serve as excellent devices for temperature detection, monitoring, indication, limiting, and over-temperature protection across various industrial and consumer applications.