中考物理基础知识（九）:第十五章 电流和电路

Basic Physics Knowledge for Senior High School Entrance Exam (9): Chapter 15 Electric Current and Circuits

李宏 湖北省十堰市郧阳中学

Li Hong Yunyang High School, Shiyan City, Hubei Province

第十五章 电流和电路-[中考物理基础知识]

Chapter 15: Electric Current and Circuits - [Basic Physics Knowledge for High School Entrance Examination]

90．自然界中只有两种电荷：正电荷和负电荷。

There are only two types of electric charges in nature: positive charge and negative charge.

（1）被丝绸摩擦过的玻璃棒带正电荷；

A glass rod rubbed with silk becomes positively charged;

（2）被毛皮摩擦过的橡胶棒带负电荷。

A rubber rod rubbed with fur becomes negatively charged.

91．同种电荷互相排斥，异种电荷互相吸引。

Like electric charges repel each other, whereas unlike electric charges attract each other.

92．电路的基本组成：

Basic components of a circuit:

（1）电源：提供电能的装置；

Power source: a device that supplies electrical energy;

（2）用电器：消耗电能的装置；

Electrical device: a device that consumes electrical energy;

（3）开关：控制电路通断的元件；

Switch: a component that controls the on/off state of the circuit;

（4）导线：连接电路。

Conducting wires: connect the components in the circuit.

93．两种基本电路的连接方式：

Two basic circuit connection methods.

94．电流表的使用：

Use of an ammeter:

（1）电流表必须和被测用电器串联；

The ammeter must be connected in series with the electrical device being measured;

（2）电流必须从正接线柱流入，负接线柱流出；

The current must flow into the ammeter through the positive terminal and out through the negative terminal;

（3）选择合适的量程（0～0．6A; 0～3A）

Select an appropriate range (0–0.6 A; 0–3 A).

95．电流用符号“Ｉ”表示,电流的单位是安培，符号是“A”。

Current is denoted by the symbol "I", and its unit is the ampere, with the symbol "A".

96．串、并联电路的电流规律：

Current rules for series and parallel circuits:

（1）串联电路中各处电流都相等；（即I串=I1=I2）

In a series circuit, the current is the same at all points (i.e., I_series = I₁= I₂);

（2）并联电路中，干路中的电流等于各支路中的电流之和。（即I并=I1+I2）

In a parallel circuit, the total current in the main circuit equals the sum of the currents in the individual branches (i.e., I_parallel = I₁+ I₂).

Explorer of Innovative Thinking

Author: Li Hong

Yunyang High School, Shiyan City, Hubei Province

February 9, 2026