How do temperature sensors work? They are devises to measure temperature readings through electrical signals. The Medical Temperature Sensor is made up of two metals, which generate electrical voltage or resistance once it notices a change in temperature. The temperature sensor plays a critical role in maintaining a specific temperature within any equipment used to make anything from medicine to beer. To produce these types of content, the accuracy and responsiveness of the temperature and temperature control are critical to ensuring the end product is perfect. Temperature is the most common physical measurement type in industrial applications. Accurate measurements are vital in ensuring the success of these processes. There are many applications that are not-so-obvious, which use temperature sensors. Melting chocolate, using a blast furnace, controlling a hot air balloon, freezing substances in a lab, running a motor vehicle, and firing a kiln.
The below contact temperature sensors:
Gas-filled & Liquid Thermometer: These thermometers are similar in terms of how they work. There is a bulb either filled with gas or liquid. This is situated inside the sensing end of the probe. When heated, the gas expands/liquid heats up which signals the attached rod to move the needle to the temperature being measured.
What is a Thermistor and how does it work?
Thermistors are a type of semiconductor, meaning they have greater resistance than conducting materials, but lower resistance than insulating materials. The relationship between a thermistor’s temperature and its resistance is highly dependent upon the materials from which it’s composed. The manufacturer typically determines this property with a high degree of accuracy, as this is the primary characteristic of interest to thermistor buyers. ;
Thermistors are made up of metallic oxides, binders and stabilizers, pressed into wafers and then cut to chip size, left in disc form, or made into another shape. The precise ratio of the composite materials governs their resistance/temperature “curve.” ;
Thermistors are available in two types: those with Negative Temperature Coefficients (NTC thermistors) and those with Positive Temperature Coefficients (PTC thermistors). NTC thermistors’ resistance decreases as their temperature increases, while PTC thermistors’ resistance increases as their temperature increases. Only NTC thermistors are commonly used in temperature measurement. ;
Thermistors are composed of materials with known resistance. As the temperature increases, an NTC thermistor’s resistance will increase in a non-linear fashion, following a particular “curve.” The shape of this resistance vs. temperature curve is determined by the properties of the materials that make up the thermistor. ;
Thermistors are often selected for applications where ruggedness, reliability, and stability are important. They’re well suited for use in environments with extreme conditions, or where electronic noise is present. They’re available in a variety of shapes: the ideal shape for a particular application depends on whether the thermistor will be surface-mounted or embedded in a system, and on the type of material being measured. ;
Using Epoxy to Protect NTC Thermistors
An Epoxy Bead NTC Thermistor temperature sensor appears as a tear-drop-shaped bead with two radial wire leads. Very often these types of NTC thermistor temperature sensors are used with applications in proximity to moisture. Some of these applications include medical devices that measure the airflow and air temperature. Epoxy bead thermistors are also frequently used in automotive applications to monitor and control air conditioning and seat warming for passenger cabins.
It is critical that NTC thermistors are protected from direct exposure to fluids, such as water or oil. To accomplish this, thermally conductive epoxy is used as an encapsulant, called “potting,” to seal the NTC thermistor temperature sensors in a stainless steel housing. This epoxy not only protects the NTC sensor from moisture but enables good thermal conduction from the medium being measured to the thermistor sensor. The thermally conductive epoxy provides operating effectiveness without degradation.
Thin Film NTC Thermistor
NTC thermistorThermal Component Technologies has released a new Thin Film NTC Thermistor. The Thin Film Type NTC Thermistor is frequently used for applications where space is a concern and the standard design is not thin enough. A typical thickness of 0.55mm offers the solution engineers have been looking for. They are an ideal choice for precise temperature measurement between flat surfaces where quick time response is critical. The thermistor chip is loaded between 2 conductors and then sandwiched with polyimide insulation. This provides excellent moisture resistance, along with flexibility. All the usual benefits of thermistors where sensitivity to temperature change is paramount.