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Influence of some factors on testing simple chaotic oscillation circuit

2021-10-14 06:39:23 Zhuo Qing

Jane Medium : By testing several related factors of chaotic oscillation circuit , Some basic laws are summarized . This provides experimental data for exploring the mechanism of the chaotic oscillation circuit .

key word triode , Chaotic circuit

 

§01 Jane Easily chaotic circuit


One 、 Preliminary test results

   In Bowen A chaotic circuit composed of two transistors Describes the use of two BC547B Composed of Chaotic circuit .

1、 The circuit principle diagram

   This circuit is composed of Kajnjaps stay Build a Chaos Generator in 5 minutes! The article gives . its The schematic diagram is shown in the figure below .

▲  chart 1.1.1.1  Two transistor chaotic circuit

▲ chart 1.1.1.1 Two transistor chaotic circuit

2、 test result

(1) Build the experimental circuit

   The test circuit built on the bread board is shown in the figure below . among R5 A potentiometer is used for adjustment .

▲  chart 1.1.2.1  The test circuit built on the bread board

▲ chart 1.1.2.1 The test circuit built on the bread board

(2) Test the waveform

   Use an oscilloscope to measure X-Y Display mode to display Q1 Collector and C1 Voltage waveform on . With R5 Different resistance values , You can see that in a certain resistance range (40k ~ 60k Ω) The circuit will produce chaotic oscillation .

▲  chart 1.1.2.2   With resistance R5 Different , The circuit oscillation mode is changing

▲ chart 1.1.2.2 With resistance R5 Different , The circuit oscillation mode is changing

Two 、 Existing problems

   During the pre-test , The following questions remain :

  • The influence of working voltage on the circuit ;
  • The influence of triode on circuit ;
  • Coupling parameters in the circuit R5,R3 Influence on circuit, etc .

   By means of TB Triode kit purchased from Experimental tests are carried out for the above different problems ; According to the test results, the design of the circuit is analyzed の Explore the operation principle .

 

§02 No Same as triode


One 、 Type and performance of triode

1、 Triode purchased

   Here's from TB I bought it from TO-92 Encapsulated triode , Suitable for testing on bread board .

▲  chart 2.1.1  Purchased TO-92 Different triodes

▲ chart 2.1.1 Purchased TO-92 Different triodes

▲  chart 2.1.2 TO-92 Model in triode

▲ chart 2.1.2 TO-92 Model in triode

2、 Triode parameters

   Use Transistor recommended test module Test the mechanism characteristics of the purchased triode .

model species Pin hFE Vbe Ic remarks
9012 PNP E-B-C 339 3.1mA 673mV
9013 NPN E-B-C 261 1.8mA643mV
9014 NPN E-B-C 366 2.2mA 663mV
9015 PNP E-B-C 335 3.1mA 661mV
8050 NPN E-B-C 224 2.1mA 633mV
8550 PNP E-B-C 341 3.1mA 626mV
2N2222 NPN E-B-C 253 1.7mA 610mV
2N3904H NPN\E-B-C 186 1.7mA 651mV
2N3904B NPN E-B-C 347 2.1mA 664mV
2N3905 PNP E-B-C 169 1.6mA 660mV
2N3906 PNP E-B-C 355 3.2mA 660mV
A1015 PNP E-C-B 366 3.3mA 658mV
C1815 NPN E-C-B 373 2.2mA 647mV
C945 NPN E-C-B 373 2.2mA 651mV
2N5401 PNP E-B-C 180 1.7mA 636mV
2N5551 NPN E-B-C 162 1.2mA 624mV
BC327 PNP C-B-E 299 2.7mA 630mV
BC337 NPN C-B-E 202 1.9mA 611mV
BC517 NPN C-B-E 116k 5.4mA 1.19V
BC547B NPN C-B-E 311 2.0 651mV 547:50V; 546:80V
BC548B NPN C-B-E 380 2.3mA 643mV
BC549B NPN C-B-E 333 2.1mA 655mV Low noise
BC550 NPN C-B-E 353 2.1mA 647mV
BC556B PNP C-B-E 370 3.4mA 665mV
BC557 PNP C-B-E 309 2.8mA 656mV
BC558B PNP C-B-E 319 2.9mA 644mV
9018 NPN E-B-C 114 0.89mA 714mV
A92 PNP E-B-C 159 1.5mA 630mV
A94 PNP E-B-C 116 1.1mA 610mV
A42 NPN E-B-C 145 1.1mA 611mV

Two 、 Test chaotic circuits

One 、 Use 2N3904

   There are two models on hand 2N3904

  • 2N3904H: hFE Only 186
  • 2N3904B:hFE Yes 347

   Test the performance of these two transistors in chaotic circuits .

(1)2N3904H

   Chaotic oscillation can occur .
▲  chart 2.2.1.1  R5 A change in the form of oscillation caused by change

▲ chart 2.2.1.1 R5 A change in the form of oscillation caused by change

(2)2N3904B

▲  chart 2.2.1.2   Use 2N3904B

▲ chart 2.2.1.2 Use 2N3904B

2、 Use 9013

   test result , Chaotic circuit can form chaotic oscillation .

3、 Use 9014

   test result , Chaotic circuit can form chaotic oscillation .

3、 Use 9018

   test result , Chaotic circuit can not form chaotic oscillation . This may be due to 9018 Of hFE Caused by too small .

3、 Use BC517

  BC517 Is a Darlington tube . test result , The circuit always oscillates , But it can't form chaotic oscillation .

 

§03 No Same as working voltage


   measuring For the case of chaotic oscillation under different working voltages .

One 、 Low voltage

   When the voltage is lower ,R5 The potentiometer changes the range , The smaller the range of chaotic oscillation . When the voltage is less than 3.5V Left and right ,R5 It is difficult to adjust it into chaotic oscillation .

Two 、 high voltage

   stay 5V ~ 25V in , Circuits can be in R5 Enter chaotic oscillation state in a large range . As the voltage increases , Enter the chaotic oscillation state R5 The higher the upper limit .

▲  chart 3.1.1  Trajectory in chaotic oscillation state

▲ chart 3.1.1 Trajectory in chaotic oscillation state

 

§04 No Identical R3 resistance


   measuring Try different R3 Influence of resistance on chaotic oscillation . In the initial circuit R3 The values for 15kΩ.

One 、 Reduce R3

1、 test R3=10k

   take R3 Reduce to 10k ohm :

  • It's easier for a circuit to go into chaos ;
  • The signal C1 The voltage on the increases ;

▲  chart 4.1.1.1 R3=10k Under the circumstances

▲ chart 4.1.1.1 R3=10k Under the circumstances

2、 test R3=4.7k

   It is difficult for the test circuit to enter the chaotic oscillation state .

Two 、 Test with resistance box

   Use resistance box instead of R3 It can be changed flexibly R3 size , test R3 Influence of size on chaotic circuit .

1、R3 The lower limit of

   Adjust the resistance box , Around the 5.5k ohm , The circuit will not produce chaotic oscillation .

▲  chart 4.2.1.1 R3=5.5k Sinusoidal oscillation produced by

▲ chart 4.2.1.1 R3=5.5k Sinusoidal oscillation produced by

   In the same R5 Under the circumstances , take R3 Change to 5.6kΩ when , Circuits can produce chaotic oscillations .

▲  chart 4.2.1.2 R3=5.6k Chaotic oscillation caused by

▲ chart 4.2.1.2 R3=5.6k Chaotic oscillation caused by

2、R3 Upper limit

   When conditions R3 To 35kΩ When , Readjust R5 It is difficult to make the circuit enter the chaotic oscillation state . The following is in the near case , The chaotic oscillation of the circuit .

   It can be seen that the oscillation amplitude is very small .

▲  chart 4.2.1.3 R3=35kΩ The corresponding critical chaotic oscillation state

▲ chart 4.2.1.3 R3=35kΩ The corresponding critical chaotic oscillation state

 

§ Test conclusion


   through Several related factors of chaotic oscillation circuit are tested , Some basic laws are summarized . This provides experimental data for exploring the mechanism of the chaotic oscillation circuit .


■ Links to related literature :

● Related chart Links :

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