This sensor operation due to changes in temperature around the sensor, detection results in the form of electrical signals instead converted into electrical signals, usually in the form of an electric voltage. And generally any change in the 10 ° C to produce electricity at 1mV dc voltage. The temperature sensor has several models and types of sample temperature sensor on the market, including PTC, NTC, PT100, LM35, thermocouple and others. Here are the characteristics of some types of temperature sensors.
Image Characteristics of some types of temperature sensors
In the picture above and thermocouple sensor IC has the most excellent linearity, but because in this task the measured temperature of over 100 ° C, the thermocouple is most appropriate because it is able to reach a temperature of 1200 o C. The linear sensor IC capable of up to 135 o C.
PTC and NTC
Thermistor or thermal prisoners are semiconductor components that have character as a prisoner with a high temperature coefficient of resistance, which is usually negative. There are two types of thermistors are often encountered in electronic devices, namely NTC (Negative Thermal Coeffisien) and PTC (Positive Thermal Coeffisien). Generally prisoners thermistor at room temperature can be reduced 6% for every increase in temperature 1oC. High sensitivity to temperature change makes very suitable thermistor for measurement, control and precision temperature compensation.
Thermistor made of a mixture of metal oxides deposited such as manganese (Mn), nickel (Ni), cobalt (Co), copper (Cu), iron (Fe) and uranium (U). Summary prisoner is from 0.5 W to 75 W and are available in various shapes and sizes. The smallest size mani-shaped beads (beads) with a diameter of 0.15 mm to 1.25 mm, the shape of the disk (disk) or the ring (washer) with a size of 2.5 mm to 25 mm. The rings can be pinned and placed in series or in parallel in order to increase the power dissipation.
In operation the thermistor utilizing resistivity change with temperature, and generally the value of his prisoner down exponentially with temperature for the type of NTC (Negative Thermal Coeffisien)