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
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
（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
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 2.1.2 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
（2）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
§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
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
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
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
§： 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 :
- A chaotic circuit composed of two transistors
- Chaotic circuit
- Build a Chaos Generator in 5 minutes!
- TB Triode kit purchased from
- Test resistance and capacitance A good helper of diodes and triodes Transistor test display module
● Related chart Links :
- chart 1.1.1.1 Two transistor chaotic circuit
- chart 1.1.2.1 The test circuit built on the bread board
- chart 1.1.2.2 With resistance R5 Different , The circuit oscillation mode is changing
- chart 2.1.1 Purchased TO-92 Different triodes
- chart 2.1.2 TO-92 Model in triode
- chart 2.2.1.1 R5 A change in the form of oscillation caused by change
- chart 2.2.1.2 Use 2N3904B
- chart 3.1.1 Trajectory in chaotic oscillation state
- chart 4.1.1.1 R3=10k Under the circumstances
- chart 4.2.1.1 R3=5.5k Sinusoidal oscillation produced by
- chart 4.2.1.2 R3=5.6k Chaotic oscillation caused by
- chart 4.2.1.3 R3=35kΩ The corresponding critical chaotic oscillation state