Research and Multisim Simulation of linear circuit characteristics (engineering documents attached)

Catalog

4.1  The experiment purpose

4.2  Experimental principle

 4.3   Experiment content and steps

4.4  Experimental requirements and precautions

4.5  Experimental report and thinking questions

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4.1  The experiment purpose

1. Deepen the understanding of the main characteristics of linear circuits （ Homogeneity 、 Superposition 、 Replaceability 、 reciprocity ） The understanding of the .

2. Research methods for learning the main characteristics of linear circuits .

4.2  Experimental principle

1. Homogeneity ： In a linear circuit with an independent source , Every response （ Voltage or current ） It is linear with the value of the independent source , That is, when an independent source increases or decreases k Times , The voltage or current generated by it on each element also increases or decreases k times . It is called the homogeneity of linear circuit （ Or proportionality ）.

2. Superposition ： In a linear circuit composed of multiple independent sources , Every response （ Voltage or current ） It can be regarded as the algebraic sum of the response produced by each independent source acting alone , This feature is called superposition （ Or superposition theorem ）.

3. Replaceability ： In linear or nonlinear circuits with unique solutions , If the voltage of a branch is known to be u, The current is i, Then this branch can be used “us=u” Voltage source replacement , Or use “is=i” Current source instead of . Replace the voltage in other parts of the rear circuit 、 The current keeps the original value .

A branch of the theorem can be passive , It can also have independent sources , Or a two terminal circuit （ Also known as generalized Branch ）. however , There should be no coupling between the replaced branch and other parts of the original circuit .

4. reciprocity ： In passive linear two terminal pair networks without controlled sources , No matter which end pair is used as the excitation end , Which end pair is the response end , The ratio of its current response to its voltage excitation is the same , Or the ratio of its voltage response to its current excitation is the same . Figuratively speaking, it is a voltage source （ Or a current source ） And an ammeter （ Or a voltmeter ） You can exchange positions with each other , And ammeter （ Or voltmeter ） The reading of does not change . This feature is called reciprocity （ Or reciprocity ）, Available diagram 4-1 Express .

 4.3   Experiment content and steps

1. Research on superposition theorem of linear circuit （1） According to the circuit diagram 4-2, Build the circuit diagram . （2） After setting up the experimental circuit , Measure when the power supply US1 、US2 Separate action （ Connect only one power supply ） When acting simultaneously with , Voltage in each branch （ Or current ）, Fill in the table 4-1 in , And calculate the power consumed on the resistance of each branch and the power provided by the power supply , Study the following problems respectively ：

chart 4-2  Experimental circuit of superposition theorem research

1） Voltage in any branch of the circuit （ Or current ） Whether it conforms to the superposition theorem with the power supply ？ answer ： accord with

2）US1、US2 When acting at the same time, the power consumed on any resistive element is equal to US1、US2 Whether the sum of the power consumed on the resistive element when acting alone conforms to the superposition theorem ？ answer ： Do not conform to the

3） Power Supply US1、US2 At the same time, the total power consumed by the circuit and US1、US2 Whether the sum of the power provided when acting alone conforms to the superposition theorem ？ answer ： Do not conform to the

Take counterclockwise as the reference direction of current .

surface 4-1  Research on superposition theorem

		US1	US2	UR1	UR2	UR3	PR1mw	PR2mw	PR3mw
US1、US2 At the same time	Theoretical value	4	2	-2.4	1.6	0.4	9.6	8.5328	0.5332
	Measured value	4	2	-2.4	1.6	0.4	9.6	8.5328	0.5332
US1 Acting alone	Theoretical value	4	-	-3.2	-0.8	-0.8	17.0656	2.1336	2.1336
	Measured value	4	-	-3.2	-0.8	-0.8	17.0656	2.1336	2.1336
US2 Acting alone	Theoretical value	-	2	0.8	0.8	1.2	1.0664	2.1336	4.8
	Measured value	-	2	0.8	0.8	1.2	1.0664	2.1336	4.8
Stack result		-	-	-2.4	1.6	0.4	18.132	4.2672	6.9336

（US1、US2 Measurement results when acting at the same time ）

（US1 Measurement results when acting alone ）

（US2 Measurement results when acting alone ）

2. Research on the homogeneity of linear circuits

According to the figure 4-2 Experimental circuit , send US1=0V（ take US1 Remove the power , Connect with a short wire R1、R2 Both ends ）. By table 4-2 Measurement data , Fill in the table .

surface 4-2  Research on circuit homogeneity

voltage Power Supply	UR1（V）		UR2（V）		UR3（V）		IR2（mA）
Theoretical value	Measured value	Theoretical value	Measured value	Theoretical value	Measured value	Theoretical value	Measured value
US2=2V	0.8	0.8	0.8	0.8	1.2	1.2	2.667	2.667
US2=4V	1.6	1.6	1.6	1.6	2.4	2.4	5.333	5.333
US2=5V	2	2	2	2	3	3	6.667	6.667

（US2=2V Measurement results ）

（US2=4V Measurement results ）

（US2=5V Measurement results ）

3. Research on reciprocity theorem of linear circuit ：

（1） According to the figure 4-3(a) The original circuit is connected to the circuit （ Map 4-2 Medium US2 Replace with an ammeter ,US1 keep 5V No change ）, measure IR3 Current value , Record the data in the table 4-3.

（2） reciprocity US Power supply and IR3 ammeter （ Map 4-2 Medium US1 Replace with an ammeter ,US2 keep 10V No change ）, Pictured 4-3(b). measurement IR1 Current value , Record the data in the table 4-3.

surface 4-3  Study of reciprocity theorem

	Original circuit	Reciprocity circuit
Theoretical value	IR3=  3.333  mA	IR1=    6.667  mA
Measured value	IR3=  3.333  mA	IR1=    6.667  mA

（ Circuit measurement results before reciprocity ）

（ Circuit measurement results after reciprocity ）

4.4  Experimental requirements and precautions

1. Pay attention to the correct use of multimeter .

2. Power supply voltage values in all measuring circuits , The value measured by the multimeter shall prevail .

4.5  Experimental report and thinking questions

1. List the measurement data sheets .

2. Analyze the measurement results , Deepen the understanding of three important theorems .

3. Thinking questions ：

Why does the power not conform to the superposition theorem ？ Try to analyze the reason .

answer ： The superposition theorem is applicable to the voltage of linear non time varying Networks 、 Calculation of current , and P=I²R or P=U²/R,P And voltage 、 The relationship between currents is no longer linear , Therefore, the superposition theorem cannot be used to calculate power directly .

Beginner circuit analysis , There may be mistakes , Also ask everybody not hesitate to grant instruction .

Due to the text , The relevant experimental projects in this paper cannot be shown , Resources have been uploaded , You can download it yourself .

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