1. Visual illuminometer: inconvenient to use, not very accurate, rarely used
2. Photoelectric illuminance meter: commonly used selenium photovoltaic illuminance meter and silicon photovoltaic illuminance meter
The composition and use requirements of the photocell illuminance meter:
1. Composition: Microammeter, shift knob, zero point adjustment, binding post, photocell, V(λ) correction filter, etc.
Commonly used selenium (Se) photocell or silicon (Si) photocell illuminometer, also known as lux meter
2. Requirements for use:
The illuminometer probe is made of glass, which is easy to be broken and damaged. At the same time, the waterproof effect is very poor when used.
① Photocells use selenium (Se) photocells or silicon (Si) photocells with good linearity; they can maintain good stability after long-term operation, and have high sensitivity; when high E, choose high internal resistance photocells, which have low sensitivity and good linearity , not easily damaged by strong light exposure
②There is a V(λ) correction filter inside, which is suitable for the illumination of different color temperature light sources, and the error is small
③ A cosine angle compensator (opal white glass or white plastic) is added in front of the photocell because when the incident angle is large, the photocell deviates from the cosine law
④The illuminometer should work at room temperature or close to room temperature (photocell drift changes with temperature)
