A negative reading on a laser power meter can be confusing during laser measurements. After all, lasers produce positive optical power, so how could a sensor display, for example, β5 W? With thermopile-based laser power sensors, the answer usually lies in the temperature gradient inside the. Why is the kW (Active Power) showing a negative reading on the Powerlogic series of meter? The Current transformers (CT's) have been fitted onto the cable or busbar the wrong way round. The P1 side of the CT should be towards the supply and the P2 side of the CT should be towards the load. These meters report a lagging power factor as positive vars (inductive) and a leading power factor as negative vars (capacitive). It's very useful in many jobs, especially in communications, fiber optics, andelectronics. All of our surgical devices and whether they are working correctly and producing the appropriate amount.