The third Lab on 2012-2-6

Today is the third lab day. What we have done are observering the chaotic waveforms on the digital oscilloscope. In order to obtain clearer waveforms, the resistor is changed to 820hm.

Chaotic waveform of diode 1N4004  with different amplitude


According to the results, as the amplitude increases, the chaotic behavior become more obvious.

Figure1:Chaotic waveforms with input signal 2V at 90KHz (Diedie 1N4004)

Figure2:Chaotic waveforms with input signal 6V at 90KHz (Diedie 1N4004)

Chaotic waveforms with input signal 8.6V at 90KHz (Diedie 1N4004)




Chaotic waveforms with input signal 16V at 90KHz (Diode 1N4004)

Chaotic waveform of diode 1N4002 with different amplitude (including Pspice simulation)


According to the results, as the amplitude increases, the chaotic behavior become more obvious. The graphs simulated on PSPICE are similar to experimental results.

Chaotic waveforms with input signal 2V at 90KHz (Diode 1N4002)

Pspice simulation of chaotic waveforms with input signal 2V at 90KHz (Diode 1N4002)




Chaotic waveforms with input signal 6V at 90KHz (Diode 1N4002)

Pspice simulation of chaotic waveforms with input signal 6V at 90KHz (Diode 1N4002)



Chaotic waveforms with input signal 8.6V at 90KHz (Diode 1N4002)

Pspice simulation of chaotic waveforms with input signal 8.6V at 90KHz (Diode 1N4002)

Chaotic waveform of D1N4004 with different frequency

According to the results, as the frequency is closed to resonance frequency, the chaotic behavior become more obvious.

The following photos shows the waveforms on the oscilloscope with different frequency and same input amplitude of 11.8 V.



Chaotic waveforms at 90KHz (1N4004)




Chaotic waveforms at 100KHz (1N4004)




Chaotic waveforms at 110KHz (1N4004)




Chaotic waveform of diode 1N4002  with different frequency (including Pspice simulation)

According to the results, as the frequency is closed to resonance frequency, the chaotic behavior become more obvious. The graphs simulated on PSPICE are similar to experimental results.

Chaotic waveforms at 103KHz (1N4002)

Pspice simulation of chaotic waveform at 103KHz (1N4002)

Chaotic waveforms at 113KHz (1N4002)

Pspice simulation of chaotic waveform at 113KHz (1N4002)   

Chaotic waveforms at 123KHz (1N4002)

Pspice simulation of chaotic waveform at 123KHz (1N4002) 

Waveform of output voltage (including Pspice simulation)


This photo shows the output signals measured across the resistor. The graphs simulated on PSPICE are similar to experimental results.

The output signals (IN4002)

Spectrum of output voltage

This is the FFT mode of the output signals, which shows the spectrum of the output voltage.

The spectrum of output voltage is continuous, which implicates that the waveform of output voltage is aperiodic.



The FFT mode of the output waveform (Diode 1N4004)



The FFT mode of the output waveform (Diode 1N4002)