A digital thermometer uses a completely different mechanism than that of the older models, and uses a probe that reads different levels of electricity, which reacts according to the temperature. Colder temperatures result in more electricity flowing through, while warmer temperatures have the opposite effect. The temperatures are then transmitted from the probe to a microchip, which converts them into the degrees found on the display.
Older thermometers use a liquid metal called mercury, which expands as the temperature in an environment increases. Although considered effective, newer technologies allow for faster temperature readings. These readings are the main difference between mechanical and electrical thermometers.
Although older thermometers are accurate, their main weakness has to do with their inability to quickly change and readjust themselves. Electronic thermometers react to temperature change using electronic impulses that occur on the probe found inside the unit. Every new electrical pulse sends out a different reading to the thermometer. This means that just as quickly as it figures out the temperature of an object, the unit can read another temperature. However, this can also pose a problem for those that use this thermometer. Due to how quickly the thermometer reads the temperature, the numbers on the display can change according to the environment, leading to confusing results.