to fig4 b when the trigger is squeezed to position two 46 output e2 is energized allowing further processing beyond wait point 58 specifically when trigger is in position two 46 the time between pulses is calculated based upon output from the indication detector 62 and system clock 64 the 2processing then proceeds to compute the electrical demand measured in kilowatts according to the indicated formula and the stored parameters of watt hour constant and any multiplier further processing allows storage of the result as well as the display of the electrical demand in kilowatts as shown in phantom in fig4 b it is noted that the second function of key 34 1 34 of the keypad 54 may be utilized for displaying the calculated value in watts from the foregoing it should be appreciated that leaving the trigger in position zero 42 the keypad may be energized allowing entry of new parameters or acceptance of previously stored parameters upon further squeezing of trigger to position one 44 the laser scanner 30 is energized along with the photodetectors 36 and the signal conditioner 60 allowing acquisition of a pulse train indicative of each passing of the black mark 16 of the disk 14 still further squeezing of the trigger to position two 46 causes computation of electrical demand in kilowatts or if desired watts importantly the positioning of the laser power meter 30 with the vertically disposed scanning laser beam 32 positioned transversely to the horizontally disposed rotating disk 14 assures accurate detecting of each passing of the black mark 16 on the edge 18 of the disk 14.