The N-type thermocouple is used to measure temperature differences between two points. This thermocouple consists of two wires that are connected at their ends. One wire is called the hot junction and the other is called the cold junction. When current flows through the hot junction, heat is generated. If the current flows through the cold junction, then the opposite effect occurs. A voltage is created across the two junctions, and this voltage can be measured using a voltmeter.