"Measurement of Voltage" PPT

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"Measurement of Voltage" PPT

Part One: Experimental Exploration

Does the ammeter read when the switch is closed?

When the power supply is not connected, how do free electrons move and whether there is any current generated?

When there is no power supply in the circuit, these charges cannot move directionally and cannot form current.

How do free electrons move when connected to a power source? Will an electric current form?

Who is driving the directional movement of charges?

When a power supply is connected to a circuit, the free electrons in the conductor move in a direction driven by the power supply, forming an electric current.

Voltage measurement PPT, Part 2: Voltage

Symbol——U

1. The function of power supply is to provide voltage to the circuit

The role of voltage and the cause of current flow in a circuit

2. The unit of voltage is volt; abbreviated as volt; symbol V;

Commonly used units: kilovolts (kV), millivolts (mV), microvolts (μV)

Conversion relationship: l kV = 103 volts

l volt = 103 millivolts

l millivolt = 103 microvolts

Voltage measurement PPT, Part 3: Voltage measurement

1. An instrument for measuring voltage - voltmeter

2. The laboratory voltmeter has three binding posts

Two measuring ranges:

0-3V, minimum scale 0.1V

0-15V, minimum scale value 0.5V

Use of voltmeter

1. The voltmeter must be connected in parallel to both ends of the circuit (electrical appliance) under test.

2. Connect the "+" terminal of the voltmeter to the end connected to the positive pole of the power supply.

3. The measured voltage cannot exceed the range of the voltmeter.

4 Allows a voltmeter to be connected in parallel to measure voltage at both ends of the power supply

Voltage measurement PPT, Part 4: Precautions

Before measuring voltage with a voltmeter, the voltage value to be measured should be estimated.

If it cannot be estimated, what should be done?

trial and error method

You can first connect a circuit other than the voltmeter to one of the terminals of the voltmeter.

After turning off the switch, quickly touch the other terminal of the voltmeter with the wire.

Observe the deflection speed of the voltmeter pointer,

If the speed is too fast, it means that the voltage being measured is too large.

Need to replace the voltmeter with a larger range

The trial touch method also has another use in experimental operations.

You can determine whether the terminals are connected reversely.

If the pointer deflects in the opposite direction,

It is necessary to change the wire connection method;

Voltage measurement PPT, Part 5: Summary:

1. The function, unit and common voltage values ​​of voltage:

2. Use of voltmeter:

3. Voltage rules of series circuits and parallel circuits:

The total voltage of a series circuit is equal to the sum of the voltages across each part of the circuit

U=U1+U2

In a parallel circuit, the total voltage is equal to the voltage across each branch.

U=U1=U2

Voltage measurement PPT, Part 6 content: Classroom exercises

1. Voltage is represented by letters, the unit is _____, abbreviated as _____, and represented by the symbol _____.

2. A voltmeter is an instrument used to measure the size of _____. The symbol is _____.

3. The voltmeter used in the laboratory has three terminals: "_____", "_____", "_____"

or"_____","_____","_____".

Two measuring ranges: _____ and _____, the minimum scale values ​​are _____ volts and _____ volts respectively.

4. Use of voltmeter:

(1) The voltmeter _____ must be connected to both ends of the circuit under test;

(2) Connect the "+" terminal of the voltmeter to the end connected to the positive pole of the power supply;

(3) The measured voltage cannot exceed the _____ of the voltmeter, and the range can be selected using the _____ method;

(4) Allow the voltmeter to be directly connected to the two poles of the power supply to measure the power supply voltage.

5. The power supply voltage is the cause of directional movement of _____ in the circuit to form _____.

6. Voltage characteristics of series circuit: __________; Voltage characteristics of parallel circuit: __________;

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"Measurement of Voltage" PPT courseware download:

"Measurement of Voltage" PPT courseware download Part 1: Voltage 1. Voltage causes the free charges in the circuit to move directionally to form a current. 2. The power supply is a device that provides voltage. 3. The symbol for voltage: _____. 4. The main international unit of voltage: _____ ..

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Update Time: 2024-07-02

This template belongs to science courseware Zhejiang Education Edition Eighth Grade Science Volume 1 industry PPT template

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