闭合电路中的能量转化及功率问题是教材重点,也是高考热点.本单元重点有两个方面:一要理解闭合电路中的能量转化关系——电功是电能转化成其他形式能的量度,电热是电能转化成内能的量度,掌握纯电阻电路、非纯电阻电路中电功和电热的关系.二要理解闭合电路中的各种电功率:电源的总功率(P=EI)、电源内部消耗功率(P_内=I~2r)和电源输出功率(P_出=P_总-P_内=UI);电动机的输入功率、输出功率和电动机内部消耗的热功率等等.闭合电路中的能量转化 Closed circuit energy conversion and power problems is the focus of the textbook, but also hot entrance.This unit focuses on two aspects: First, to understand the closed circuit in the energy conversion relationship - Electrical power is converted into other forms of energy can be measured, electric Is a measure of the conversion of electrical energy into internal energy, grasp the relationship between electrical work and electrothermal in a purely resistive circuit, a non-pure resistance circuit. Second, understand the various electrical power in the closed circuit: total power of the power supply (P = EI), internal power consumption Power (P_ = I ~ 2r) and the power output power (P_ out = P_ total-P_ within = UI); motor input power, the output power and the motor internal thermal power consumption, etc. Closed circuit Energy conversion