A simple and inexpensive (called a microcontroller) inside the digital thermometer determines the thermistor's temperature by measuring its electric resistance. The microcontroller then displays the temperature on a liquid crystal-based screen.

? Let's us see the previous digital thermometer . The above instruments suffered from the disadvantage that they were also barometers, ie sensitive to air pressure. In about 1654 Ferdinando II de 'Medici, Grand Duke of Tuscany, made sealed tubes part filled with alcohol, with a bulb and stem, the first modern-style Digital Thermometer, depending on the expansion of a liquid, and independent of air pressure. Many other scientists experimented with various liquids and designs of thermometer.