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Problem on a chaotic circuit.

  1. Dec 25, 2013 #1
    windows screen capture
    So I built this circuit(Chua's chaotic circuit) and I have to take it to the lab for plugging it to oscilloscope.I need to make sure it works, cause I won't have any time there to fix it or rebuild it.So when I i tested it with the multimeter,there was no voltage on the left side and there was a voltage of a constant value on capacitors(I checked the connections and everything is okay).So is this because of the frequency? Or am I doing something wrong?(Note:left side has to behave like an inductor)
  2. jcsd
  3. Dec 25, 2013 #2


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    Could you supply a circuit diagram?

    Check all wiring. The power supply pins on the ICs should have the right voltages on them. These stay constant so they are a good starting point.
  4. Dec 25, 2013 #3
    This is the schematic: chuas_circuit_realized_labeled2_with_batteries.jpg .

    This is the function of a chua's diode, g(x)is resistance vs current:

    This is the double scroll

    analog_double_scroll_attractor.jpg :

    Yes, but shouldn't it oscillate?I highly doubt its a connection problem.
    Last edited: Dec 25, 2013
  5. Dec 26, 2013 #4


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    You can't tell if something is oscillating when you use a multimeter. You might get a reading on AC volts but these ranges are often pretty insensitive.

    So, you may have to wait until you get an Oscilloscope connected to it.

    Incidentally, you may be surprised how cheap oscilloscopes can get.

    Digital oscilloscopes from China have entered the market and that leaves a lot of unused, perfectly OK analog oscilloscopes available.

    There are also plenty of handheld oscilloscopes like this one:

    I don't know if you would find $70 expensive or if the 1 MHz bandwidth would be a little too low in performance for you.

    In the meantime, I would really check those voltages and connections. I don't trust breadboards, so the time to find any problems is before you leave home.

    I saw a report that said those circuits were difficult to get going, so it will be interesting to see how you get on.
    Last edited: Dec 26, 2013
  6. Dec 26, 2013 #5
    Thanks for the advice, I'll post an update on how it worked out.The reason I chose the breadboard
    over a PCB, was that I'm planning on experimenting(different combinations and values of resistance and capacity)
    As for the oscillator,I'm planning on buying the Sinometer ST16B 10MHz oscillator,cause price difference is only 100$,but quality looks a lot better.Only problem is that it says "X Y mode" does that mean that it can't graph in 3 dimensions?
  7. Dec 26, 2013 #6


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    You can't "graph in 3 dimensions" on any oscilloscope. Some scopes have a "Z" input channel that modulates the brightness of the trace as it is being drawn, but that's not the same as creating 3-D graphics.
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