光敏电阻应用电路

光敏电阻应用电路 光敏电阻的应用 1(光控开关电路 图2-38所示是一种光控开关电路～这一光控开关电路可以用在一些楼道、路灯等公共场所。通过光敏电阻器～它在天黑时会自动开灯～天亮时自动熄灭。电路中～VS1是晶闸管～Rl是光敏电阻器。 当光线亮时～光敏电阻器Rl阻值小～220V交流电压经VD1整流后的单向脉冲性直流电压在RP1和Rl分压后的电压小～加到晶闸管VS1控制极的电压小～这时晶闸管VS1不能导通～所以灯HL回路无电流～灯不亮。 当光线暗时～光敏电阻器Rl阻值大～RPI和Rl分压后的电压大～加到晶闸管VS1控制极的电压大～这时晶闸管VS1进入导通状态～所以灯HL回路有电流流过～灯点亮。 2(灯光亮度自动调节电路 图2-39所示是灯光亮度自动调节电路～这一电路能根据外界光线的强弱来自动调节灯光亮度。电路中～VS1是晶闸管～N是氖管～HL是灯～R3是光敏电阻器。 method of basic operation; including CT, and MRI various contrast, and Image-guided biopsy, ultrasound, etc. (11) teaching, scientific research and training in clinical teaching, written within three years with some level of review or book reports of not less than 1. Four, to read reference books, Journal of internal medicine (medical college planning materials) and of the medical imaging (medical college planning materials); the practical science; the Harrison Science (in English), Chinese Journal of internal medicine series. Surgical surgical specialist refers to the rules complete the medical undergraduate or graduate education Foundation, accepted and adopted surgical specialist training, surgical diagnosis, treatment, prevention and follow-up of common diseases, surgical diagnosis and treatment of rare or incurable diseases, acute and critical illness in emergency and rescue have preliminary knowledge and experience. Surgical specialist training for 3 years. A surgical specialist, training goals through training, trainees to achieve surgical specialist level, with more skilled surgical skills, can guide the teaching of 电路中～晶闸管VS1和二极管VD1，VD4组成全波相控电路～用氖管N作为VS1的触发管。 220V交流电通过负载HL加到VD1，VD4桥式整流电路中～整流后的单向脉冲直流电压加到晶闸管VS1阳极和阴极之间～VS1导通与截止受控制极上的电压控制。整流后的电路还加到各电阻和电容上。 直流电压通过Rl和RP1对电容Cl进行充电～Cl上充到的电压通过氖管N加到晶闸管VS1控制极上～当Cl上电压上升到一定程度时～氖管N启辉～将电压加到晶闸管VS1控制极上～使晶闸管VS1导通～灯HL点亮。 电容Cl上平均电压大小决定了晶闸管VS1交流电一个周期内平均导通时间长短～从而决定了灯的亮度。 当外界亮度高时～光敏电阻器R3阻值小～Cl的充电电压低～晶闸管VS1平均导通时间短～HL灯光就暗。 当外界亮庋低时～光敏电阻器R3阻值大～Cl的充电电压高～晶闸管VS1平均导通时间长～HL灯光就亮。 由于R3的阻值是随外界光线强弱自动变化的～所以灯HL的亮度也是受外界光线强弱自动控制的。 调节可变电阻器RP1阻值可以改变对电容Cl的充电时间常数～即改变VS1的导通角～调节HL灯光的亮度。 3(停电自动报警电路 图2—41所示是停电自动报警电路。电路中～VD2是method of basic operation; including CT, and MRI various contrast, and Image-guided biopsy, ultrasound, etc. (11) teaching, scientific research and training in clinical teaching, written within three years with some level of review or book reports of not less than 1. Four, to read reference books, Journal of internal medicine (medical college planning materials) and of the medical imaging (medical college planning materials); the practical science; the Harrison Science (in English), Chinese Journal of internal medicine series. Surgical surgical specialist refers to the rules complete the medical undergraduate or graduate education Foundation, accepted and adopted surgical specialist training, surgical diagnosis, treatment, prevention and follow-up of common diseases, surgical diagnosis and treatment of rare or incurable diseases, acute and critical illness in emergency and rescue have preliminary knowledge and experience. Surgical specialist training for 3 years. A surgical specialist, training goals through training, trainees to achieve surgical specialist level, with more skilled surgical skills, can guide the teaching of 交流电电源指示灯～VD4是红色发光二极管～R4是光敏电阻器～BL1是扬声器～VT1、VT2和周围元器件构成一个低频振荡器。 有交流市电时～220V交流电压通过VD半波整流和Cl滤波～得到的直流电压通过Rl加到VD2上～使之发光指示交流电供电正常。同时～通过R2加到VD3上～使VD3发光。 由于VD3发光～光线照射到光敏电阻器R4上～R4阻值小。这时～+3V直流电压通过R3和R4分压的电压加到VT1基极～因为R4阻值小～VT1截止～这时报警电路不工作。 当交流电断电时～VD3不发光～R4阻值明显增大～使VT1进入放大状态～这时VT1、VT2等周围元器件构成的低频振荡器电路工作～扬声器BL1发出声响报警～同时VD4发光显示断电。 电路中～R5和C2构成低频振荡器中的正反馈电路。 method of basic operation; including CT, and MRI various contrast, and Image-guided biopsy, ultrasound, etc. (11) teaching, scientific research and training in clinical teaching, written within three years with some level of review or book reports of not less than 1. Four, to read reference books, Journal of internal medicine (medical college planning materials) and of the medical imaging (medical college planning materials); the practical science; the Harrison Science (in English), Chinese Journal of internal medicine series. Surgical surgical specialist refers to the rules complete the medical undergraduate or graduate education Foundation, accepted and adopted surgical specialist training, surgical diagnosis, treatment, prevention and follow-up of common diseases, surgical diagnosis and treatment of rare or incurable diseases, acute and critical illness in emergency and rescue have preliminary knowledge and experience. Surgical specialist training for 3 years. A surgical specialist, training goals through training, trainees to achieve surgical specialist level, with more skilled surgical skills, can guide the teaching of 4(熙相机电子测光电路 图2-43所示是照相机电子测光电路。在中档照相机中～光敏电阻器作为电子测光元件。电路中～Rl是光敏电阻器～R2是热敏电阻器～VD1和VD2是发光二极管。 从电路中可以看出～VT1是VD1的驱动管～VT2是VD2的驱动管～VT1和VT2两端的电路对称～但是基极偏置电路有所不同。VT2基极由固定电阻R6、R7构成分压式偏置电路～而VT1基极则由R1、RP1和R2构成分压式偏置电路。 光线从孔板照射在光敏电阻器上～ITR9707 移动密度板时可以改变光线照射到光敏电阻器Rl上的强弱～从而可以改变Rl的阻值大小～改变Rl、RP1和R2分压电路输出电压～即改变了加到VT1基极的直流电压～进而改变了发光二极管Vmethod of basic operation; including CT, and MRI various contrast, and Image-guided biopsy, ultrasound, etc. (11) teaching, scientific research and training in clinical teaching, written within three years with some level of review or book reports of not less than 1. Four, to read reference books, Journal of internal medicine (medical college planning materials) and of the medical imaging (medical college planning materials); the practical science; the Harrison Science (in English), Chinese Journal of internal medicine series. Surgical surgical specialist refers to the rules complete the medical undergraduate or graduate education Foundation, accepted and adopted surgical specialist training, surgical diagnosis, treatment, prevention and follow-up of common diseases, surgical diagnosis and treatment of rare or incurable diseases, acute and critical illness in emergency and rescue have preliminary knowledge and experience. Surgical specialist training for 3 years. A surgical specialist, training goals through training, trainees to achieve surgical specialist level, with more skilled surgical skills, can guide the teaching of D1发光强弱～达到正确曝光的目的。 电路中的热敏电阻R2 (lkΩ)起温度补偿作用～以补 偿光敏电阻器Rl的温度变化而引起的误差。 method of basic operation; including CT, and MRI various contrast, and Image-guided biopsy, ultrasound, etc. (11) teaching, scientific research and training in clinical teaching, written within three years with some level of review or book reports of not less than 1. Four, to read reference books, Journal of internal medicine (medical college planning materials) and of the medical imaging (medical college planning materials); the practical science; the Harrison Science (in English), Chinese Journal of internal medicine series. Surgical surgical specialist refers to the rules complete the medical undergraduate or graduate education Foundation, accepted and adopted surgical specialist training, surgical diagnosis, treatment, prevention and follow-up of common diseases, surgical diagnosis and treatment of rare or incurable diseases, acute and critical illness in emergency and rescue have preliminary knowledge and experience. Surgical specialist training for 3 years. A surgical specialist, training goals through training, trainees to achieve surgical specialist level, with more skilled surgical skills, can guide the teaching of