LED的电流与光强之间的关系

01测量LED的电流与光强

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在前面制作光强传感器的实验中，测试过LED的电流与光强之间的关系。对于不同的LED电流 与光强非线性关系也不同。

为了进一步验证这个关系与所使用的单片机电路没有关系，使用万用表逐点侧袋电流与光强之间的关系，对于前面单片机的AD测量的关系进行验证。

1. SP-45ML光电二极管放大电路设计
2. LED亮度与电流之间的关系？

(1) 测量方案

使用DP1308(程控电源)输出可调电压，施加在LED与测量电流的电阻（1kΩ），通过测量电阻上的电压获得LED的电流。

使用在 SP-45ML光电二极管放大电路设计 中的电路测量光强。

02测量结果

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1.红外LED

^{▲ 红外LED电流与光强之间的关系}

c=[0.00,0.00,-0.00,-0.00,-0.00,0.00,-0.00,-0.00,0.00,0.00,0.00,0.00,0.01,0.01,0.03,0.06,0.09,0.13,0.17,0.22,0.27,0.32,0.37,0.42,0.47,0.52,0.58,0.63,0.68,0.74,0.79,0.85,0.90,0.96,1.01,1.07,1.12,1.18,1.23,1.29,1.34,1.40,1.45,1.51,1.57,1.62,1.68,1.73,1.79,1.85,1.90,1.96,2.02,2.07,2.13,2.18,2.24,2.30,2.35,2.41,2.47,2.52,2.58,2.64,2.69,2.75,2.81,2.86,2.92,2.98,3.03,3.09,3.15,3.20,3.26,3.32,3.37,3.43,3.49,3.54,3.60,3.66,3.71,3.77,3.83,3.88,3.94,4.00,4.06,4.11,4.17,4.23,4.28,4.34,4.40,4.45,4.51,4.57,4.62,4.68]

i=[0.15,0.15,0.15,0.15,0.15,0.15,0.15,0.15,0.15,0.14,0.14,0.14,0.14,0.14,0.15,0.15,0.15,0.15,0.16,0.17,0.17,0.18,0.20,0.21,0.23,0.24,0.26,0.28,0.30,0.32,0.35,0.37,0.40,0.42,0.45,0.48,0.51,0.54,0.57,0.60,0.63,0.66,0.69,0.73,0.76,0.80,0.83,0.87,0.90,0.94,0.98,1.01,1.05,1.09,1.13,1.17,1.20,1.24,1.28,1.32,1.36,1.40,1.45,1.49,1.53,1.57,1.61,1.65,1.69,1.74,1.78,1.82,1.86,1.91,1.95,1.99,2.03,2.08,2.12,2.17,2.21,2.25,2.30,2.34,2.39,2.43,2.48,2.52,2.57,2.61,2.66,2.71,2.75,2.80,2.84,2.89,2.93,2.98,3.03,3.07]

2.红色LED

^{▲ 红色LED电流与光强之间的关系}

c=[0.00,0.00,-0.00,-0.00,0.00,-0.00,-0.00,-0.00,-0.00,-0.00,-0.00,-0.00,-0.00,-0.00,-0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.01,0.02,0.04,0.07,0.11,0.16,0.20,0.25,0.30,0.35,0.40,0.46,0.51,0.56,0.62,0.67,0.72,0.78,0.83,0.89,0.94,1.00,1.05,1.11,1.16,1.22,1.27,1.33,1.38,1.44,1.50,1.55,1.61,1.66,1.72,1.77,1.83,1.89,1.94,2.00,2.05,2.11,2.17,2.22,2.28,2.34,2.39,2.45,2.50,2.56,2.62,2.67,2.73,2.78,2.84,2.90,2.95,3.01,3.07,3.12,3.18,3.24,3.29,3.35,3.41,3.46,3.52,3.58,3.63,3.69,3.75,3.80,3.86,3.92,3.97,4.03,4.08,4.14]

i=[0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.13,0.14,0.16,0.18,0.20,0.22,0.24,0.27,0.29,0.32,0.35,0.37,0.40,0.43,0.45,0.48,0.51,0.54,0.57,0.60,0.62,0.65,0.68,0.71,0.74,0.77,0.80,0.83,0.86,0.89,0.92,0.94,0.97,1.01,1.03,1.06,1.09,1.12,1.15,1.18,1.21,1.24,1.27,1.30,1.33,1.36,1.39,1.41,1.44,1.47,1.50,1.53,1.56,1.59,1.62,1.65,1.68,1.71,1.74,1.77,1.80,1.82,1.85,1.88,1.91,1.94,1.97,2.00,2.03,2.06,2.08,2.11,2.14,2.17,2.20]

3.绿色LED

^{▲ 绿色LED电流与光强之间的关系}

4.蓝色LED

^{▲ 蓝色LED电流与光强之间的关系}

c=[0.00,0.00,0.00,0.00,0.00,0.00,0.00,-0.00,0.00,0.00,-0.00,-0.00,-0.00,-0.00,-0.00,-0.00,-0.00,0.00,0.00,-0.00,-0.00,0.00,-0.00,-0.00,-0.00,-0.00,-0.00,-0.00,-0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.01,0.01,0.03,0.06,0.10,0.15,0.19,0.24,0.29,0.34,0.39,0.45,0.50,0.55,0.60,0.66,0.71,0.76,0.82,0.87,0.93,0.98,1.03,1.09,1.14,1.20,1.25,1.30,1.36,1.41,1.47,1.52,1.58,1.63,1.69,1.74,1.80,1.85,1.91,1.96,2.02,2.07,2.13,2.18,2.24,2.29,2.35,2.40,2.46,2.52,2.57,2.63,2.68,2.74,2.79,2.85,2.90,2.96,3.01,3.07,3.12,3.18,3.24,3.29]

i=[0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.12,0.14,0.17,0.21,0.24,0.28,0.32,0.36,0.40,0.45,0.49,0.53,0.57,0.61,0.66,0.70,0.74,0.78,0.83,0.87,0.91,0.95,1.00,1.04,1.08,1.12,1.16,1.21,1.25,1.29,1.33,1.37,1.41,1.45,1.49,1.54,1.58,1.62,1.66,1.70,1.74,1.78,1.82,1.86,1.90,1.94,1.98,2.02,2.06,2.10,2.14,2.18,2.22,2.26,2.30,2.33,2.37,2.41,2.45,2.49,2.53,2.57]

5.白色LED

^{▲ 白色LED电流与光强之间的关系}

c=[0.00,0.00,0.00,-0.00,0.00,-0.00,0.00,-0.00,0.00,0.00,0.00,0.00,0.00,-0.00,-0.00,-0.00,-0.00,-0.00,-0.00,0.00,-0.00,0.00,-0.00,-0.00,-0.00,0.00,0.00,-0.00,-0.00,-0.00,-0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.01,0.04,0.07,0.12,0.16,0.21,0.26,0.32,0.37,0.42,0.47,0.53,0.58,0.64,0.69,0.75,0.80,0.86,0.91,0.97,1.02,1.08,1.13,1.19,1.24,1.30,1.36,1.41,1.47,1.52,1.58,1.64,1.69,1.75,1.80,1.86,1.92,1.97,2.03,2.09,2.14,2.20,2.25,2.31,2.37,2.42,2.48,2.54,2.59,2.65,2.71,2.76,2.82,2.88,2.93,2.99,3.05,3.10,3.16,3.22,3.27,3.33,3.39]

i=[0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.12,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.11,0.12,0.13,0.15,0.18,0.22,0.25,0.29,0.33,0.37,0.41,0.45,0.49,0.53,0.58,0.62,0.67,0.71,0.75,0.80,0.84,0.89,0.93,0.98,1.02,1.07,1.12,1.16,1.21,1.25,1.30,1.34,1.39,1.44,1.48,1.53,1.57,1.62,1.67,1.71,1.76,1.80,1.85,1.90,1.94,1.99,2.04,2.08,2.13,2.18,2.22,2.27,2.32,2.36,2.41,2.45,2.50,2.55,2.59,2.64,2.69,2.73,2.78,2.82]

※ 结论

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通过实验验证了LED的电流是光强之间的关系。对于不同颜色的LED这个非线性关系呈现不同的变化。其中的物理原理有待进一步的解释。

#!/usr/local/bin/python
# -*- coding: gbk -*-
#============================================================
# TEST3.PY                     -- by Dr. ZhuoQing 2020-07-30
#
# Note:
#============================================================

from headm import *
from tsmodule.tsvisa        import *
from tsmodule.tsstm32       import *

dp1308open()
setv = linspace(0.3, 6, 100)

cdim = []
idim = []

for v in setv:
    dp1308p6v(v)
    time.sleep(1.5)
    meter = meterval()

    cdim.append(meter[3])
    idim.append(meter[0])

    printf(meter)

tspsave('wled', c=cdim, i=idim)
printf('\a')
plt.plot(cdim, idim)
plt.xlabel("Current(mA)")
plt.ylabel("Intensity")
plt.grid(True)
plt.tight_layout()
plt.show()

#------------------------------------------------------------
#        END OF FILE : TEST3.PY
#============================================================

※ 实验计划

（1）可以通过LED来测试SP-45ML在低亮度下的线性性；
（2）对于LED大电流饱和下的亮度。

1. 弱光的电流

^{▲ 白色LED电流与光强之间的关系}

^{▲ 白色LED电流与光强之间的关系}

^{▲ 白色LED在小电流下的电流与光强之间的关系}

2. 大电流LED光强

^{▲ 白色大电流与光强之间的关系}

^{▲ 蓝色大电流与光强之间的关系}

^{▲ 绿色大电流与光强之间的关系}

^{▲ 红色LED电流与光强之间的关系}

^{▲ 红外LED电流与光强之间的关系}

3.巨大电流关系

^{▲ 白色LED电流与光强}

^{▲ 红色LED电流与光强之间的关系}

^{▲ 绿色色LED电流与光强之间的关系}

^{▲ 蓝色LED电流与光强之间的关系}