How do you know the solar thermometer receive sunlight?

Many common solar thermometer in our life, we all know, the solar thermometer is the use of solar energy and the cable sensors provide accurate temperature indicator, so you know how to receive sunlight solar thermometer is? Today we'll DST2002S, for example, to tell you about this problem. Models: DST2002S types: solar digital display material: stainless steel shell, stainless steel temperature measuring head header: 50 mm table: PC thermal line length: 1. 2 meters temperature range: - 50/150℃, ℉ : precision & plusmn; 1C( - - - - - - 20~50C) Resolution: 0. 1° C installation: flange dashboard after installation you can see, this solar thermometer which has a bright LCD display, easy reading, display here is a black chip, it is a solar wafer, is to rely on it to receive the sun, when light levels high 100 lux will show that the temperature of the object to be tested; When the light levels drop, with a backup battery to provide power to continue to display circuit. The power switch ( OFF/ON） Equipped with can have the effect of saving electricity, more environmentally friendly.