照度计
Illuminometer
照度计是一种专门测量光度、亮度的仪器仪表，常用于测量室内灯具的照度。它所测的光照强度就是物体被照明的程度，也即物体表面所得到的光通量与被照面积之比。照度计通常是由硒光电池或硅光电池，以及微安表组成。照度测量应采用不低于一级的照度计。
Illumination meter is a special instrument for measuring luminosity and brightness. It is often used to measure illuminance of indoor lamps. The light intensity it measures is the degree to which the object is illuminated, that is, the ratio of the luminous flux obtained on the surface of the object to the illuminated area. Luminometer is usually composed of selenium photocell or silicon photocell and microampere meter. Illuminance measurement shall be made with an illuminometer not lower than Class I.
光电池是把光能直接转换成电能的光电元件。当光线射到硒光电池表面时，入射光透过金属薄膜4到达半导体硒层2和金属薄膜4的分界面上，在界面上产生光电效应。产生电位差的大小与光电池受光表面上的照 度有一定的比例关系。这时如果接上外电路，就会有电流通过，电流值从以勒克斯（Lx）为刻度的微安表上指示出来。光电流的大小取决于入射光的强弱和回路中的电阻。照度计有变档装置，因此可以测高照度，也可以测低照度。
Photovoltaic cells are photoelectric elements that directly convert light energy into electrical energy. When light rays are incident on the surface of the selenium photovoltaic cell, the incident light passes through the metal film 4 to reach the interface between the semiconductor selenium layer 2 and the metal film 4, generating a photoelectric effect on the interface. The magnitude of the generated potential difference is proportional to the irradiance on the light receiving surface of the photovoltaic cell. At this time, if an external circuit is connected, a current will pass through, and the current value will be indicated from the microampere meter with Lux (Lx) as the scale. The photocurrent depends on the intensity of the incident light and the resistance in the loop. The illuminometer is a shift device, so it can measure both high illuminance and low illuminance.
