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    • #6295

        Hi all,

        So far, we had sine waves, square waves with PWM. Now let’s build a triangle wave generator in no less than 2 minutes 😆

        The Lectron start and expansion sets have all the parts needed.

        As a  change, let’s build the circuit following the picture :

        Triangle wave generator

        By adjusting the speed with th 250K potentiometer, we will notice that lamp is fading in and out.

        This triangle is not perfectly linear, as seen in the oscillograph here, but it resembles very close :



        Can you guess what the Lectron meter indicates ?

        We will explain the working principle later (maybe you can give it a try ?)

        Some cool hints 😉

        • Exchange the 10µF capacitor with a 0,47µF capacitor.
        • Change the 10K resistor onto 1,5K.
        • If you have an oscilloscope, measure the pulse at the lamp connection.
        • Remove the capacitor and measure the same signal with the scope. What do you see ?

        Later on, we will make this sound audible and do some modifications.

        Stay tuned !

      • #6301

          Hi all,

          Wouldn’t it be cool to actually hear sounds produced by this oscillator ?

          Well, by adding a speaker and some modules, we can !

          We have to use a red wire connected to 2 contact plugs which can easily slide between two adjacent Lectron cubes. Put the red plug as shown in the picture. Use the black plug to “probe” around the circuit and hear the different sounds produced.

          An oscilloscope can come in very handy to visualize the different waveforms !

          Don’t forget to turn the potentiometer to change the pitch of the sound !

          Triangle sound generator

          For some experimenting, change the value of <span style=”color: #0000ff;”>C <span style=”color: #000000;”>to 47nF</span><span style=”color: #000000;”>. Also, change the value of <span style=”color: #0000ff;”>R<span style=”color: #000000;”> to 1,5K.</span></span>

          Have you already figured out how the circuit works ?

          A hint : <span style=”color: #0000ff;”>R</span> and <span style=”color: #0000ff;”>C</span> are responsible for the pitch of the oscillator.<span style=”color: #000000;”> The circuit is a combination of 2 basic circuits.</span>

          Can you guess which ones ?

          Give it a go, before we dive into the next experiment : a sawtooth oscillator !


          • This reply was modified 4 years, 8 months ago by Michael.
          • This reply was modified 4 years, 8 months ago by Michael.
        • #6325

            Hi Michael,

            This message is just a test for the text colors and don’t need to be published.
            On my PC screen I also see the color code embedded in the text.

            This is a color text in the Visual editor mode : <span style=”color: #0000ff;”>blue</span> <span style=”color: #ff0000;”>red</span>
            In visual mode I see the words blue and red in their corespondent colors.

            It seems I can’t change the color of the text in Text editor mode !

            Maybe the solution is to say something like “capacitor marked C” or “resistor marked R”.

            Here is my test in your text for Green an Red.

            This seems to work okMaybe it is a matter of permissions.

            • This reply was modified 4 years, 8 months ago by Michael.
            • This reply was modified 4 years, 8 months ago by Michael.
            • This reply was modified 4 years, 8 months ago by Michael.
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