"Current" Simple Circuit PPT Courseware

Description

"Current" Simple Circuit PPT Courseware

1. Current

Observe and think

Take two identical electroscopes A and B, make A charged and B uncharged.

Use a metal rod with an insulated handle to connect A and B. You can see that the opening angle of the metal foil of A is reduced, the opening angle of the metal foil of B is the same, and the opening angle of the metal foil of the last two electroscopes is the same.

1. Current and direction of current

Free electrons: Some of the electrons in an atom that are farthest from the nucleus can break free from the constraints of the nucleus and move freely throughout the metal. These electrons are called free electrons.

Free charge: A charge that can move freely.

Electric current: The directional movement of free charges forms an electric current.

1. Current intensity: indicates the size of the current

Current intensity Abbreviation Current Symbol I

2. The basic unit of electric current: Ampere, abbreviated as A, symbol A

Commonly used units: milliampere (mA) and microampere (μA)

Conversion relationship: 1A=1000mA 1mA=1000 μA

2. Ammeter

Observe and think

Ammeter: Appearance, Terminal, Range, Graduation Value

Precautions for correct use of ammeter

(1) The pointer must be reset to zero before use

(2) The ammeter should be connected in series in the circuit

(3) The current flows into the ammeter from the "0.6" or "3" terminal and flows out from the "-" terminal.

(4) Do not connect the ammeter directly to the two poles of the power supply.

(5) The size of the current being measured cannot exceed the range of the ammeter.

practise

1.Which of the following values ​​may be the current value of a household washing machine? ( )

A.40 mA B.4 A

C.400 mA D.400 μA

2. The rules for using an ammeter are:

(1) The ammeter should be connected to the circuit under test;

(2) When connecting the ammeter, the current should flow in from the __________ terminal and flow out from the _____ terminal;

(3) The current in the circuit should not exceed the _____ of the ammeter;

(4) It is never allowed to connect the ammeter directly to the power supply without going through the electrical appliance. Otherwise, it will be damaged due to _____ being too large.

3． When measuring current, if the magnitude of the current to be measured cannot be estimated in advance, the _____ method must be used to determine the range of the ammeter. The specific method is: first select _____ range and connect one terminal of the meter to the circuit, then take one wire of the circuit and _____ the other terminal of the ammeter. If the pointer of the meter does not exceed the range, fix it properly; if the pointer of the meter is too small, it means it is within the small range, then use the _____ range for measurement.

4. Before using an ammeter to measure the current in the circuit, it is estimated that the current in the measured circuit is about 0.4~0.5A. The ammeter used has three terminals: "-", "0.6A", and "3A". When measuring, you should The two terminals ______ and ______ are connected to the circuit, so that the measured results are more accurate.

5. Regarding the use of ammeter, which of the following statements is incorrect ( )

A. Before use, if the pointer of the ammeter does not point to the "0" point on the dial, it must be adjusted to zero first.

B． The ammeter should be connected in parallel in the circuit under test

C. When the current in the circuit is not estimated, a trial touch method should be used to select the appropriate range.

D． It is never allowed to connect the ammeter terminals to the two poles of the power supply without using electrical appliances.

Keywords: simple circuit teaching courseware, current teaching courseware, Beijing Normal University edition ninth grade physics PPT courseware download, ninth grade physics slide courseware download, simple circuit PPT courseware download, current PPT courseware download, .PPT format;

For more information about the "Simple Circuit Current" PPT courseware, please click on the "Simple Circuit ppt Current ppt" tab.

"The Relationship between Current, Voltage and Resistance" PPT courseware:

"The Relationship between Current, Voltage and Resistance" PPT courseware Part 1: Introduction of the topic Please look at the following experiment and think about the problem. Please think: What can be done to dim the light bulb? Method 1: Remove a battery Method 2: Add resistance to the circuit Question: Same...

"The Relationship between Current, Voltage and Resistance" PPT:

"The Relationship between Current, Voltage and Resistance" PPT Part One Content: Thinking: Which physical quantity is most susceptible to the magnitude of the current passing through a certain conductor in a certain circuit, the voltage at both ends of this conductor, and the resistance of this conductor, which physical quantity is most susceptible to the other two Due to changes in quantity...

"Measurement of Current" PPT courseware:

The first part of the "Measurement of Electric Current" PPT courseware content: The strength of electric current 1. Current: a physical quantity indicating the strength of electric current, symbol I 2. Unit: Ampere, symbol A. There are also milliamps (mA) and microamps (A) 3 , Current unit conversion relationship: 1A＝1000mA 1mA＝100..

File Info

Update Time: 2024-10-04

This template belongs to Physics courseware Beijing Normal University Ninth Grade Physics Volume 1 industry PPT template

Preview