Introduction and operating principle of illuminometer
Illuminometer (also known as Lexometer) is a specialized instrument for measuring luminosity and brightness. It consists of a host and a light sensor, with a measurement range of 0-50000. The average indoor light intensity ranges from 100-1000lux, while the outdoor sunlight intensity is approximately 50000lux. Lux is a unit of illumination that represents the density of light shining on the surface. Its main applications are indoor, office, laboratory, and environmental research.
Illuminometer - Principles of Illuminometer Measurement
Photocell is a photoelectric element that directly converts light energy into electrical energy. When light strikes the surface of a selenium photocell, the incident light passes through the metal film 4 and reaches the interface between the semiconductor selenium layer 2 and the metal film 4, generating a photoelectric effect at the interface. The magnitude of the generated photocurrent is proportional to the illumination on the surface of the photocell. At this point, if an external circuit is connected, a current will pass through, and the current value will be indicated on the microampere meter with a scale of Lx. The magnitude of photocurrent depends on the strength of the incident light. The illuminometer has a shift device, so it can measure both high and low illuminance. Types of illuminometer: 1. Visual illuminometer: inconvenient to use, low accuracy, rarely used 2. Photoelectric illuminometer: commonly used selenium photocell illuminometer and silicon photocell illuminometer
Illuminometer - Type of illuminometer:
1. Visual illuminometer: inconvenient to use, low accuracy, rarely used
2. Photoelectric illuminometer: commonly used selenium photocell illuminometer and silicon photocell illuminometer
Composition and usage requirements of photocell illuminometer:
1. Composition: microampere meter, shift knob, zero adjustment, wiring post, photocell, V（ λ) Correct the composition of filters and other components.
Commonly used selenium (Se) photocell or silicon (Si) photocell illuminometer, also known as lux meter
2. Usage requirements:
① Photocells should use selenium (Se) photocells or silicon (Si) photocells with good linearity; Maintains good stability and high sensitivity even after prolonged work; When using high E, choose photocells with high internal resistance, which have low sensitivity and good linearity, and are not easily damaged by strong light irradiation
② Internal payment with V（ λ) Correct the filter, suitable for using the illumination of a heterochromatic temperature light source, with small error
③ The reason for adding a cosine angle compensator (milky white glass or white plastic) in front of the photocell is that when the incident angle is large, the photocell deviates from the cosine rule
④ The illuminometer should operate at or near room temperature (the drift of the photocell changes with temperature)
