A digital thermometer is a device used for the measuring of temperature, and which provides a numerical reading that is usually more precise than that given by a liquid thermometer. 

A digital thermometer has many common uses both in business and everyday life, but how does a digital thermometer actually work? The devices are actually much simpler than the majority of people probably realise, with most of them working with similar technology and under the same basic principles. The only way in which digital thermometers differ is in their design and construction as well as the quality of the used components. 

How does it work?

A digital thermometer contains a resistor and a small computing mechanism. The sensor will notice any change in temperature around the thermometer and that difference in resistance will be converted into a temperature difference and expressed in degrees on a digital readout. The sensor in a digital thermometer is known as a thermistor. 

Digital thermometers that are of very high quality can be purchased fairly inexpensively due to the fact that good thermistors do not cost very much. When a good sensor is used in conjunction with other parts that are also of a very high quality and placed in a housing that is well designed, the instrument that results is one that is accurate and extremely useful that can serve its intended purpose for many years to come. 

Thermistors can be found in a wide array of electronic devices that need to take into account temperature changes and can serve as a substitute for fuses or circuit breakers by shutting down electronics that are sensitive to temperature in order to prevent any damage that would otherwise be caused by overheating. They can also be found in air conditioning and heating thermostats where they are a replacement for mercury sensors or bimetallic strips, which have an even greater likelihood of failing. 

Other types of digital thermometer

There are some types of digital thermometer that do not use a thermistor. A digital thermocouple thermometer determines temperature with two measurements, first a temperature measuring sensor where it is connected to the thermocouple, and secondly by measuring the thermometer’s MV signal. The CJC temperature is subtracted from the hot end signal and the resultant voltage then converted to temperature. 

A digital RTD thermometer is essentially an ohmmeter, which measures the sensor’s resistance by applying a small excitation current or voltage to the sensor and then measuring the voltage across it. 4-wire connections are often used for the purpose of minimising measurement errors

A digital solid state thermometer provides the sensor with an excitation current and then measures the linear analogue signal it emits. That signal is converted into a set of digital pulses.

What industries use digital thermometers?

A number of different industries make use of digital thermometers including the food, industrial maintenance, scientific research, hygiene testing, heating and ventilation and medical testing industry. 

The digital thermometers of today make possible the quick and accurate assessment of temperatures