Attention should be paid to the ambient temperature when using the UV light meter
When utilizing, caution must be taken to avoid high light exposure because the phototube's cathode will become exhausted if exposed to strong light over an extended period of time, which will result in the photocathode emitting irregularly. Therefore, when the illuminance meter is not in use, the window's protective cover should be closed. Additionally, neither a very high nor a very low temperature should be present around the ultraviolet illuminance meter.The constraints on the ambient temperature are less stringent when the photoelectric cell GD-5 is used as the receiver, especially for the ultraviolet illuminance meter that employs thermoelectric effect components as the receiver (which is typically at 20°C). In general, a lower temperature is preferable to increase the dark current. Additionally, the light source's radiation should be measured perpendicular to the receiver window when being measured. A significant inaccuracy will be made if it is slanted. At this time, an angle correction is necessary.
