Solar Led traffic lights can be seen on most equipment and circuits. What are the key parameters that need to be paid attention to when choosing the most basic LED traffic signal?
Parameter 1: Wavelength
Peak wavelength & dominant wavelength. The light that the human eye can see is not exactly the same as the light that the machine can see. So there are two wavelength indicators to express: dominant wavelength and peak wavelength.
Peak wavelength: The wavelength corresponding to the maximum spectral luminous intensity or radiant power.
Dominant wavelength: The wavelength corresponding to the color of the main light emitted by the light source can be seen by the eye as the main wavelength
Generally speaking, the two parameters have little difference. The choice mainly depends on the application. If it is used on an optical instrument, the instrument needs to identify the wavelength at this time, and the peak wavelength should prevail when selecting. If it is used for instructions, because the recipient is human, the dominant wavelength should be considered more.
Color and wavelength. There is a one-to-one correspondence between color and wavelength. If you want to find LED substitutes with the same color as before when selecting materials. The parameter of wavelength can be directly compared. If the wavelength is the same, the color is also the same. The following is the wavelength range of common colors.
Red: R (610nm-640nm)
Yellow (Yellow): Y (580nm-595nm)
Blue: B (455nm-490nm)
Green: G (501nm-540nm)
Purple (Purple): P (380nm-410nm)
Parameter 2: Luminous intensity
Luminous intensity (candela, unit mcd) is a measure of the intensity of the light source, that is, the brightness of the light that the instrument can receive.
In practical applications, the human eyes have different perceptions of light of different wavelengths. With the same radiant energy LED, we will feel that the red light is much brighter than the green light. In actual design, it is sometimes necessary to use LEDs of different colors at the same time. In order to ensure the consistency of the brightness of all LEDs, you can consider choosing a green LED with a higher luminous intensity.
Parameter 3: Forward voltage & forward current
LED is a kind of diode. Generally, in the case of forward conduction, the forward voltage Vf can be understood as the rated voltage required to make the LED emit light. The forward working current If can be understood as the rated current required to make the Solar Led traffic lights. Generally speaking, the greater the forward working current, the greater the brightness of the LED.
The greater the forward current If, the higher the temperature, and the life will be affected. When the ambient temperature is high, it is recommended to reduce the forward current for longer LEDs. Many manufacturers will list the corresponding curve of temperature and rated forward current in the data sheet.
Parameter 4: LED package
There are two main types of packaging: patch and in-line.
Generally speaking, the volume occupied by the patch will be smaller, and it can also be selected by size.