The analog output of the meter - using the mating connector provided – gives a voltage signal proportional to the actual reading (it is in fact just a D/A translation of what is being displayed), so it represents a fully calibrated reading. The full scale value is a function of the meter being used and the power range it is on. With the StarBright, Vega and Nova II, for example, the user can select full scale analog output voltage ranges of 1v, 2v, 5v or 10v, and the 100% level of the chosen power scale is scaled to the full scale voltage. For example: if you choose 5V full scale analog voltage range, and your sensor is set to a 50W full scale power range, then you will have 5V = 50W or 0.1 V/W. It will vary according to the chosen power range and chosen full scale voltage range. The electrical accuracy is stated in the specification (see the User manual) as ±0.2% (of reading) ±0.3% of full scale volts (in addition to the calibration accuracy of the sensor’s reading itself).