NTC Temperature Sensor: Working Principle, Advantages and Detailed Application Explanation

The working principle of NTC Temperature Sensor

The core feature of the NTC temperature sensor is that its resistance value changes with temperature. Specifically, the resistance value of the Ntc Temperature sensor decreases when the temperature rises and increases when the temperature drops. This physical property makes the Ntc Temperature sensor highly sensitive to temperature changes.

The structural composition of NTC temperature sensors

The conventional types of NTC temperature sensors include glass-sealed series, epoxy plastic-sealed series, metal or plastic shell encapsulated series, and one-piece injection molded series, etc. Next, let's briefly explain the structural composition of several general series:

1.Temperature sensing element：

This is the core of the NTC temperature sensor, made of ceramic chips from semiconductor materials (such as nickel oxide, cobalt oxide, etc.), which have the physical property that the resistance value is inversely proportional to the temperature. Ceramic chips can simultaneously be made into various temperature-sensing components through epoxy plastic encapsulation or glass packaging.

2.Packaging/Filling:

Epoxy resin encapsulation: The temperature sensing element is encapsulated with epoxy resin material. This encapsulation method is relatively simple, with a smaller head size, and is suitable for battery packs and some small household appliances.

Metal and plastic shell encapsulation: The temperature-sensing element is encapsulated in a shell with epoxy resin or high-temperature adhesive, which has good pressure resistance and water resistance. It is suitable for multiple application scenarios, such as new energy vehicles, industrial control devices, smart toilets, coffee machines, high-temperature ovens, etc.

3.Appearance Design:

✅ Bullet head type: Generally made of stainless steel, the bullet head has the feature of a small temperature sensing head size, which enables the sensor to sense temperature more quickly. It is usually applied to measure water temperature, such as in smart toilets, coffee machines, water dispensers, water heaters, etc.

✅ Straight pipe type: The straight pipe type is designed simply and is suitable for linear connection and general temperature monitoring.

✅ Ground ring type: Ground ring housing, also known as wire ear terminal, is suitable for installation on a flat surface for temperature measurement. It is generally installed by screwing and has the advantages of easy installation and high reliability. It is suitable for use in various industrial control products.

4.Lead wire:

As the conductor connecting the sensor to the main control board, the main materials used for lead wire include PVC, XLPE, TEFLON, etc. It can be made into double parallel wire, single wire, and sheathed wire. Different materials have different temperature resistance and can be customized according to actual applications.

Temperature measurement range

The typical temperature measurement range of NTC sensors is -50°C to 150° C. Some special models can be extended to -100°C to 300°C, but their stability will decline in high-temperature environments.

Main advantages

High sensitivity:

Large resistance change rate, capable of detecting minute temperature changes.

Fast response:

Small thermal time constant, suitable for dynamic temperature measurement.

Low cost:

Compared with PT100, thermocouples, etc., its price is more competitive.

Compact size:

Suitable for embedded applications, such as PCB mounting.

The installation method of NTC temperature sensors

 1.Surface mounting:

Use silicone to directly mount the NTC onto the surface of the object under test. It is generally suitable for products with a smaller installation area.

2.Insertable installation:

This installation method is generally suitable for products with metal casings, such as bullet-shaped casing products for measuring water temperature and metal straight tubes for measuring the cavity of an oven

Such products, etc. The insertable installation method enables the NTC to come into direct contact with the liquid, allowing for more accurate and rapid temperature measurement.

3.Installation of fixed plates:

Generally suitable for ground ring type shells, it is installed on the surface of the object to be measured by screwing or laser welding. This approach is typically applied to products such as transformers, inverters, charging stations, and BMS, and it has the advantages of strong compressive resistance and stability.

NTC temperature sensors are widely used in high-end consumer electronics, new energy vehicles, energy storage and industrial control, office automation and other fields due to their high sensitivity, high precision and strong stability. Customized according to different application scenarios and installation requirements, it enables rapid and precise temperature control of the object under test to ensure its safety and reliability. If a wider temperature range or higher accuracy is required, PT100 or thermocouple solutions can be considered.