一、直流电路电路由电源、导线、负载和控制器组成,电路一定要在开关闭路后才能正常工作。要了解电路基本物理量的定义和物理概念,要记住度量单位。要正确掌握欧姆定律,要求熟练地使用。电阻和电工材料这一节是电工常识的内容。要注意绝缘材料只能在温度、湿度、电压等条件允许的范围内工作。一般电机、电器等都有额定电压、最高温度等规格要求。 1. The DC circuit consists of a power supply, wires, a load, and a controller. The circuit must operate normally after the circuit is opened and closed. To understand the definition of a circuit’s basic physical quantity and the physical concept, remember the unit of measure. To correctly master Ohm’s law requires skilled use. The section on resistance and electrical materials is a common knowledge of electricians. It should be noted that the insulating material can only work within the temperature, humidity, voltage and other conditions. General motors, electrical appliances, etc. have specifications for rated voltage and maximum temperature.