How do LED street lights achieve light control?
2020-11-11
How do LED street lights achieve light control? Where's the light switch? A little physical knowledge will think that the photosensitive semiconductor has an automatic perception of the strength of the light, and this feature can be used to control the circuit. So where is the light control switch of the solar street lamp produced by the led street lamp manufacturer? If it is inside the light pole or underground, how to perceive the strength of the light to achieve the light control effect? Outside? Is it under the solar panels?
In response to these problems, many friends must have questions, for everyone to analyze the light control implementation of the controller we mainly use.
Location: There is no specialized similar semiconductor device, so the control switch that people imagine does not exist
Optical control components: solar panel, battery and controller
Principle: As long as the light reaches a certain degree of darkness, the solar street lamp will automatically turn on the running lighting, which is not limited by time, and is only related to the strength of the light.
How to judge: Solar street lights are mainly achieved by the controller. The controller generally has a light control point (control point) voltage, most of which is 3V, when the sun is weak, the panel voltage will continue to decline, from the normal 17.5V or 35V down to dark 0V, in the middle of the process, when less than 3V, the controller will get a dark signal, which will be delayed for a period of time (time can be set, In order to prevent this voltage drop is a temporary reduction, such as a sudden dark clouds in the daytime, or solar photovoltaic panels are blocked by things), after the delay, it is still lower than 3V, at this time the controller determines that it is dark, it will be connected to the battery and the street lamp (light source lamp), this time the street lamp constitutes a complete circuit, The light source is lit.
On the contrary, the process from dark day to day is like this: before dawn, the circuit of the battery and the lamp is connected, the lamp is illuminated, the photovoltaic panel and the battery are disconnected, and there is no closed circuit. When the day slowly gets brighter and the illuminance becomes stronger and stronger, the voltage perceived by the photovoltaic panel also slowly increases, when the photocontrol voltage value exceeds 3V, the controller will have a delay time judgment, when the delay time exceeds, the photovoltaic panel voltage is still greater than or equal to the photocontrol voltage 3V.