照度計

Illuminometer

照度計是一種專門測量光度、亮度的儀器儀表，常用于測量室內(nèi)燈具的照度。它所測的光照強度就是物體被照明的程度，也即物體表面所得到的光通量與被照面積之比。照度計通常是由硒光電池或硅光電池，以及微安表組成。照度測量應(yīng)采用不低于一級的照度計。

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.

光電池是把光能直接轉(zhuǎn)換成電能的光電元件。當光線射到硒光電池表面時，入射光透過金屬薄膜4到達半導體硒層2和金屬薄膜4的分界面上，在界面上產(chǎn)生光電效應(yīng)。產(chǎn)生電位差的大小與光電池受光表面上的照 度有一定的比例關(guān)系。這時如果接上外電路，就會有電流通過，電流值從以勒克斯（Lx）為刻度的微安表上指示出來。光電流的大小取決于入射光的強弱和回路中的電阻。照度計有變檔裝置，因此可以測高照度，也可以測低照度。

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.