A lithographic projection apparatus including an interferometer system having a reach extending over a first, measurement station and a second, exposure station. The current controlling circuit has an auto zero function in the light-emitting diode driver to eliminate offsets caused by the system, process variations, parasitic effects, dimming and so on in an LED driver application, and thus is capable of controlling the LED current with high accuracy. The insert is indexable by repositioning the cutting insert from one face to the other face.