Thermocouples and thermometers were invented to measure the temperature of human body as well as various objects. With fruitful scientific improvements, both, thermometers and thermocouples have been changed in terms of design as well as technology. Presently, there are wide varieties of thermometers and thermocouples that are available in the market.

Let's start with thermometers and its varieties. As aforementioned, thermometers are mainly used to measure human body temperatures as well as surface temperatures of different objects and machineries. Thermometers are widely used for scientific as well as engineering applications. There are various thermometers helping one to make the daily work easy and one such thermometer is handheld infrared thermometers.

Introduction of handheld infrared thermometers is proved as a boon for technicians and factory workers. Now, they can easily and promptly measure the temperature of exceptionally hot or moving surfaces without even touching the objects.  These thermometers use blackbody radiation, mostly infrared, emitted by the objects to measure the temperature. Besides these thermometers are also known as non contact infrared thermometers as temperature can be recorded from a distance. Mentioned here are few more types:
. Alcohol thermometer
. Appliance thermometer
. Baby thermometer
. Instant-Read Bimetallic-Coil thermometer
. Galileo thermometer and many more

Apart from aforementioned, USB Thermometer is also one of the latest additions in the wide range of thermometers. These thermometers come with a USB port that allows its users to connect it with desktops and laptops in order to record the indoor temperature.

Let's move towards thermocouples and its types. Similar to thermometers, thermocouples are also used to measure temperature that consist two different conductors made up of different metals. These conductors produce voltage that can be correlated back to the temperature. Thermocouples have been divided into various categories named as Type J, Type K, Type E, Type T, Type N, Type B, Type S and Type R according to their specifications and characteristics. Following are few varieties of thermocouples:
. General purpose
. Armored thermocouples
. Replacement thermocouples
. Spring loaded thermocouples
. Penetration thermocouples and more

However, mineral insulated thermocouples are the one that are widely used in industrial applications. These thermocouples can record temperature up to 2400 degree that makes it highly useable in turbines, diesel engines, rocket and jet engines, catalytic reformers, steam generators, refineries and power stations etc.  These thermocouples are also called sheathed thermocouples as they are insulated with non-reactive minerals that are covered with an alloy sheath or stainless steel.