EGT, Exhaust Gas Temperature is typically measured in the tail pipe of the engine. TGT, Turbine Gas Temperature is typically measured inside the engine either right in front of or right behind the gas producer turbine rotor wheel(s). This is also sometimes referred to as TOT or Turbine Outlet Temperature, the terms are basically interchangeable.

In the case of model turbines the aft centrifugal turbine takes the place of the individual turbine rotor(s), both perform the same task of driving the compressor or N1 section of the engine.