A、直流电压平均值U<sub>0sub>=0.45U B、直流电压平均值U<sub>0sub>=0.9U C、负载电流I<sub>Lsub>=U<sub>0sub>R<sub>Lsub>
A、直流电压平均值U<sub>0sub>=0.45U B、直流电压平均值U<sub>0sub>=0.9U C、负载电流I<sub>Lsub>=U<sub>0sub>R<sub>Lsub>
A、Z<sub>2sub>Z<sub>3sub>/(Z<sub>2sub>+Z<sub>3sub>) B、Z<sub>1sub>+Z<sub>2sub>Z<sub>3sub>/(Z<sub>2sub>+Z<sub>3sub>) C、Z<sub>1sub>+Z<sub>2sub>+Z<sub>3sub> D、Z<sub>1sub>+(Z<sub>2sub>+Z3)/(Z<sub>2sub>Z<sub>3sub>)
A、I<sub>esub>/I<sub>bsub> B、I<sub>csub>/I<sub>bsub> C、I<sub>csub>/I<sub>esub> D、I<sub>bsub>/I<sub>csub>
A、稳压管稳压电路如图所示。已知稳压管稳压值为V<sub>Zsub>=6V,稳定电流范围为I<sub>Zsub>=5~20mA,额定功率为200mW,限流电阻R=500 。试求:
A、H<sub>1sub>灯立即发亮、H<sub>2sub>灯逐渐变亮 B、H<sub>1sub>灯和H<sub>2sub>灯都立即发亮 C、H<sub>1sub>灯和H<sub>2sub>灯都逐渐变亮 D、H<sub>1sub>灯逐渐变亮、H<sub>2sub>立即发亮
A、图示所示轮系,已知Z<sub>1sub>=18、Z<sub>2sub>=20、Z<sub>2’sub>=25、Z<sub>3sub>=25、Z<sub>3’sub>=2、Z<sub>4sub>=40,求该轮系的传动比,并判断蜗轮4的转向。
A、在图示轮系中,各轮齿数为z<sub>1sub>=10,z<sub>2sub>=40,z<sub>2’sub>=15,z<sub>3sub>=30,z<sub>3’sub>=20,z<sub>4sub>=40。试求传动比i<sub>14sub>,并确定O<sub>1sub>和轴O<sub>4sub>的转向是相同还是相反?
A、I<sub>1sub>-I<sub>2sub>+I<sub>3sub>=5A B、I<sub>1sub>-I<sub>2sub>+I<sub>3sub>=-5A C、-I<sub>1sub>+I<sub>2sub>-I<sub>3sub>=0 D、I<sub>1sub>+I<sub>2sub>+I<sub>3sub>=0