AMWEI - PTC thermistors Limit Temperature Sensors
From PTC Thermistor
PTC (positive temperature coefficient)thermistorswitches at one particular temperature. Making use of the characteristics that the resistance ofPTCthermistorsincreases sharply above curie temperature, when ambient temperature increases abnormally, protective circuit installedPTCthermistorwill turn on or cut off loop through resistance changing, achieving thermal protection purpose.PTCthermistorsprotect such equipment and components as motors, transformers, power transistors and thyristors against over-temperature. APTCthermistoris less expensive than a thermostat, and its switch temperature can be more accurately specified. It is also smaller and easier to design-in to electronic circuitry. ThereforePTCthermistorscan be ideal devices for temperature detection, monitoring, indicating, limiting and over (excessive) temperature protection.
Typical Application ofPTCthermistorsfor Temperature Protection and temperature limiting sensors
- ·Limit temperature measurement of Industrial electronics application.
- Power supplies, switch power supply.
- Home appliances, such as dish washers, washing machines, ironing machines, electric cookers, etc.
- Electronic data processing and communications engineering (DC/DC converters).
- Motor windings overheating Protection.
- Automotive electronics.
- Semiconductor heatsinks, enclosure panels, temperature-limited transistors.
- Lighting applications.
PTCthermistorsLimit Temperature Sensor for Industrial Application
APTCthermistorcan be used effectively to detect whether a temperature limit in industrial equipment, liquids, etc, is exceeded. ThePTCthermistoris mounted in thermal contact with the medium that has to be protected from overheating. When the rated temperature limit of the medium is reached, the resistance ofPTCthermistorsincreases abruptly. In connection with a control unit, this signal can be used to automatically switch the power supply of a load.
Features ofPTCthermistorfor Temperature Protection and temperature limiting sensors
- 2 Outlook construction: A-radial leaded epoxy resin coated form, B-metal tag lug form. Screw type metal cases or other construction can be made upon customer request.
- PTC Thermistor Protection temperature 60C to 130C. 60C, 70C, 80C, 90C, 100C, 110C, 120C, 130C.
- Quick response.
- Long stability.
- Small dimension, convenient for installation.
- Do not need to be reset after protection.
Temperature Sensing ProtectionPTCthermistorOperating Principle
As in fig. 1, in normal ambient temperature,PTCthermistorresistance Rp lower than Rs, lower output voltage. When ambient temperature exceeds set temperature,PTCthermistorsresistance Rp increases rapidly, and exceeds Rs, and leads Vo increases to high enough voltage, and cause tripping.