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为了适应夜间行车的安全需要,有必要对现在汽车的远近灯转换开关加以改进。目前使用的是手动开关,在两车相遇时,不能及时将远灯关闭,灯光直射对面驾驶员的眼睛,容易发生交通事故。作者设计了一种汽车远近灯转换电路,该电路设有手动和自动功能,不改变原有的控制电路,不会对原有电路产生任何影响。电路分为3部分:信号取样、逻辑判断及输出控制。信号取样采用光敏二极管,光达一定强度时,二极管导通,否则截止。逻辑判断采用施密特触发电路,采用可控硅作控制开关。实验结果:在实验室中,用一只6～8V小电珠作为触发光源,改变电珠与光敏二极管的距离模拟光强的变化,用两只小电珠模拟汽车远近灯泡,将光源靠近光敏管,取样电压大于4.5V,近灯亮,远灯关闭,将光源渐渐离开,电压将逐渐减小,电压在4.5～1.7V时,保持近灯亮(此过程模拟错车期间的情况)。当电压小于1.7V时,电路翻转,远灯亮而近灯自动关闭(错车后的情况),然后又将光源逐渐靠近光敏管,电压逐渐从小到大,在0～3.4V之间,保持远灯亮,大于3.4V时,电路才翻转,近灯亮。电于充电电容较大,充放电时间长,实验中观察到,被关闭的灯渐熄灭,被点亮的灯亮度逐渐增大,给人的眼睛一个适应过程。
In order to meet the safety needs of traffic at night, it is necessary to improve the car’s near and far light switch. At present, the manual switch is used. When the two vehicles meet, the far lamp can not be turned off in time and the light is directly exposed to the eyes of the driver. Traffic accidents are easy to happen. The author designed a car near and far lamp conversion circuit, the circuit has a manual and automatic functions, do not change the original control circuit, will not have any impact on the original circuit. The circuit is divided into 3 parts: signal sampling, logic judgment and output control. Signal sampling using photodiode, light up to a certain intensity, the diode conduction, or cut-off. Logic to determine the use of Schmitt trigger circuit, SCR control switch. Experimental results: In the laboratory, using a small 6 ~ 8V beads as the trigger light source, changing the distance between the light-emitting diode and the photodiode to simulate the light intensity changes, using two small beads to simulate the car near and far bulb, the light source close to the phototube, sampling The voltage is higher than 4.5V, the near lamp is on, the far lamp is off, and the light source will gradually leave. The voltage will gradually decrease. When the voltage is 4.5 ~ 1.7V, the near lamp is on (this process simulates the situation during the wrong car). When the voltage is less than 1.7V, the circuit is turned over, the near lamp is on and the near lamp is off automatically (after the wrong car), and then the light source is gradually approached to the phototube, the voltage gradually increases from small to large, keeps the bright lamp from 0 to 3.4V When the voltage is larger than 3.4V, the circuit will be reversed and the near lamp will turn on brightly. Electric charge in the larger capacitor, charging and discharging a long time, the experiment was observed, the lamp is turned off off gradually, the brightness of the lamp is gradually increased, giving the human eye an adaptation process.