The turbine, which is almost always a radial inflow turbine (but in large Diesel engines is almost always a single-stage axial inflow turbine)
The compressor, which is almost always a centrifugal compressor.
The center housing/hub rotating assembly.
Of course, the vehicles need these things to run but there are also smaller components that are just as important.
The speed sensor is one of the important devices and it detects the rotational speed of exhaust-gas turbochargers. By doing so, it provides a key input parameter for the efficient management of the turbocharging system.