An analog EGT (Exhaust Gas Temperature) probe is essentially a temperature detector that that works without electricity because it relies on thermocouplers.

A Thermocoupler consists of two wire legs made from different metals. These legs are welded at one end to create a junction and this is where the temperature is measured. If heat is applied to the junction, the metal expands generating a tiny electrical pulse called ‘Seebeck voltage’. The voltage being generated is directly correlated to the heat being applied and the type of metals being used in the thermocoupler. Conversely, if we know the volts being generated, we can figure out the temperature.

Of course, one does not need to sit with a calculator or for that matter, do any calculation to figure out the temperature in the airc ... Read more »