Hardware analysis and detailed explanation of RC series and parallel frequency selection network characteristics

Catalog

One ． Purpose

Two ． Principle analysis

3、 ... and ． equipment

Four ． Hardware analysis

1. measurement ＲＣ strand 、 Amplitude frequency characteristics of parallel circuit

 2. measurement ＲＣ strand 、 Phase frequency characteristics of parallel circuit

3. Determination ＲＣ double Ｔ Amplitude frequency characteristic of circuit

5、 ... and ． matters needing attention

6、 ... and ． Summary and reflection

1. According to the circuit parameters , Estimate ＲＣ strand 、 Resonance frequency of parallel circuit with two sets of parameters .

2. deduction ＲＣ strand 、 Amplitude frequency of parallel circuit 、 Mathematical expression of phase frequency characteristics .

 3. What is? ＲＣ strand 、 Frequency selection characteristics of parallel circuit ？ When the frequency is equal to the resonant frequency , The output of the circuit 、 What is the relationship between input ？

4. Try qualitative analysis ＲＣ double Ｔ Amplitude frequency characteristic of circuit .

7、 ... and ． numerical analysis

One ． Purpose

1. Research ＲＣ strand 、 Parallel circuit and ＲＣ double Ｔ Frequency characteristics of the circuit .

2. Learn to use oscilloscope to measure ＲＣ Amplitude frequency characteristics and phase frequency characteristics of the network .

3. Be familiar with the structural characteristics and frequency selection characteristics of Wen's bridge circuit .

Two ． Principle analysis

3、 ... and ． equipment

1. Signal source （ Self provided ）;

2. Dual trace oscilloscope ( Self provided ).

3.EEL－51S Components 、 Weak current component box ;

Four ． Hardware analysis

1. measurement ＲＣ strand 、 Amplitude frequency characteristics of parallel circuit

The experimental circuit is shown in the figure 15－3 Shown , among ,RC The parameter selection of the network is ：Ｒ＝200Ω,Ｃ＝２.２μＦ（ stay

NEEL—003 Components ）, The signal source outputs sine wave voltage as the input voltage of the circuit ｕi, Adjust the output voltage amplitude of the signal source , send Ui＝2V.

Change the frequency of the sine wave output voltage of the signal source  f（ Read by the frequency meter ）, And keep Ui=2V unchanged , Measure the output voltage U 0 ,（ First measure A = 1/3 The frequency of time fo, And then in fo Select several frequency points on the left and right , measurement U 0 ）, Record the data in the table 15－1 in . In the figure 15－3 Of RC In the network , Choose another set of parameters ：Ｒ＝2kΩ,Ｃ＝0.1μＦ, Repeat the above measurements , Put the data

Record in table 15－1 in .

surface 15－1    Amplitude frequency characteristic data

 2. measurement ＲＣ strand 、 Phase frequency characteristics of parallel circuit

The experimental circuit is shown in the figure 15－3 Shown , According to the description of measuring phase frequency characteristics in the experimental principle , The experimental procedure is the same as that of the experiment 1, Record the experimental data in the table 15－2 in .

3. Determination ＲＣ double Ｔ Amplitude frequency characteristic of circuit

The experimental circuit is shown in the figure 15－3 Shown , among RC Network by map 15－5 Connect , The experimental procedure is the same as that of the experiment 1, Record the experimental data in the self-made data table .

surface 15－2    Phase frequency characteristic data

5、 ... and ． matters needing attention

Due to the influence of the internal resistance of the signal source , Note that when adjusting the output voltage frequency , The output voltage should be adjusted at the same time , Keep the input voltage of the experimental circuit unchanged .

6、 ... and ． Summary and reflection

1. According to the circuit parameters , Estimate ＲＣ strand 、 Resonance frequency of parallel circuit with two sets of parameters .

It can be inferred from the formula , The resonant frequency is f=1/2πRC=361Hz

2. deduction ＲＣ strand 、 Amplitude frequency of parallel circuit 、 Mathematical expression of phase frequency characteristics .

 3. What is? ＲＣ strand 、 Frequency selection characteristics of parallel circuit ？ When the frequency is equal to the resonant frequency , The output of the circuit 、 What is the relationship between input ？

ＲＣ strand 、 The parallel circuit can have an appropriate choice of frequency , Make the output of a certain frequency small or large , When f=fo when ,

RC The output voltage of the series parallel circuit is in phase with the input voltage , The size is equal to that of the input voltage 1/3.

4. Try qualitative analysis ＲＣ double Ｔ Amplitude frequency characteristic of circuit .

7、 ... and ． numerical analysis

1. According to the table 15－1 And table 15－2 experimental data , draw ＲＣ strand 、 Two groups of amplitude frequency characteristic and phase frequency characteristic curves of parallel circuit , Find out the maximum value of resonant frequency and amplitude frequency characteristics , And compared with the theoretical value .

R=2KΩ C=0.1mF Amplitude frequency characteristic and phase frequency characteristic curve

R=200Ω, C=2.2mF Amplitude frequency characteristic and phase frequency characteristic curve

Within the allowable range of error , The theoretical value is equal to the measured value .

2. According to the experiment 3 The experimental data of , draw ＲＣ double Ｔ Amplitude frequency characteristic of circuit , And explain the characteristics of amplitude frequency characteristics .