The Thermistor thermometer is often referred to as semi conductor equipment that is proportional to temperature. It also has some degree of electrical resistance that carries a negative or positive temperature resistance that decreases by 3 percent per degree Celsius.
What is unique about this device is that it differs from typical resistance temperature detectors. This is because the material used in the device is usually made from polymer or ceramic while RTDs utilize pure metals.
There are two kinds of thermistors that are commonly used today. These are in the form of Positive Temperature Coefficient of Resistance or PTC and the Negative Temperature Coefficient of Resistance or NTC. NTCs are the thermistor that has an inverse relation with the resistance and temperature of the object.
It means that if there is an increase in the object’s temperature, there will also be a proportional decrease in its resistivity and vice versa. With PTC, this device witnesses the same change in the resistance and temperature of the object. In simpler terms, if there is an increase in the resistance, the temperature will also increase and vice versa.
Making a Measurement
because they are resistive devices, people should supply them with an excitation source and then read the voltage across the terminal. This source should be precise and constant. People should take temperature measurements by simply connecting them differentially into an analog input channel.
In other words, an individual should connect both the –ve and +ve terminals of the device’s analog input channel. If there is the presence of more than two wires, the additional wires should solely be used for connecting to the excitation source. A four-way or three-way connection method places leads on a high-impedance path via the measurement device. This effectively attenuates the error caused by any lead-wire resistance.
A Wide Range of Use
These devices are widely used nowadays in a number of medical applications. They are appropriately used as medical probes or in clinical stethoscopes at the time of surgery in order to avoid overheating in circuits in addition to ECG and X-ray machines.
At the same time, they are used in a wide range of devices such as amplifiers, computers and cell phones. They also have an important role in industrial applications. They are commonly used in devices such as photographic processing equipment, welding equipment and fluid flow equipment.