An inverter device for variably controlling an operating frequency of an electric motor, which drives a compressor in a refrigerating cycle. In either configuration, such modes further contain optical paths from a source system through a small-volume or large-volume sample to a spectrometer based system. The engaging element includes a groove or pressed line where the body can be lifted, which connects with the two sides thereof, and the cover is divided along the groove or pressed line into two parts, namely the engaging element and the body. By synchronizing the light flashes with the mirror driving signal and measuring the amount of light reflected by the individual micromirrors at different points in time, the transient behavior characteristics of individual micromirrors in a DMD micromirror array can be measured with a high level of accuracy. The translated addresses identify the location of the two-bit memory cells within the non-uniform core two-bit memory cell array.