Introduction and working principle of illuminance meter
1. Illuminance meter:
An illuminance meter (or lux meter) is an instrument that specializes in measuring luminosity and brightness. Is to measure the light intensity (illuminance)
It is the degree to which the object is illuminated, that is, the ratio of the luminous flux obtained by the surface of the object to the illuminated area. An illuminance meter is usually composed of a selenium photocell or a silicon photocell and a microammeter.
2. Measuring principle:
Photovoltaic cells are photoelectric components that directly convert light energy into electrical energy. When the light hits the surface of the selenium photovoltaic cell, the incident light passes through the metal thin film 4 and reaches the interface between the semiconductor selenium layer 2 and the metal thin film 4, generating a photoelectric effect on the interface. The magnitude of the generated photocurrent has a certain proportional relationship with the illuminance on the light-receiving surface of the photocell. At this time, if an external circuit is connected, a current will flow, and the current value will be indicated on a microammeter with a scale of lux (Lx). The magnitude of the photocurrent depends on the intensity of the incident light. The illuminance meter has a shifting device, so it can measure high illuminance or low illuminance.
Types of illuminance meters cited: 1. Visual illuminance meter: inconvenient to use, low accuracy, rarely used 2. Photoelectric illuminance meter: selenium photocell illuminance meter and silicon photocell illuminance meter are commonly used.
