题干

小明同学家里的电热饮水机有加热和保温两种功能,可由机内温控开关S0进行自动控制.小明从说明书上收集到如下表中的部分数据和如图所示的电路原理图.

额定电压

220V

频率

50Hz

额定加热功率

920W

请解答如下问题:(计算结果若不能整除,保留一位小数)

(1)这个电热饮水机正常工作时,在加热状态下的总电流大约是多大?

(2)若电阻R2的阻值为1210Ω,则电阻R1的阻值为多少?

(3)在傍晚用电高峰期,供电电压可能会下降.当实际电压只有198V时,这个电热饮水机加热的实际功率是多大?

上一题 下一题 0.0难度 选择题 更新时间:2018-05-12 01:55:27

答案(点此获取答案解析)

解:(1)正常加热状态下的电流:I=≈4.2A;(2)当开关S闭合、S0断开时,电热饮水机只有R2

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