<b>Narration</b>

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Welcome to the spoken tutorial on “<b>PCB Layout for Astable Multivibrator</b>”.

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In this tutorial, we will learn to -
<p>Create a <b>PCB layout</b> for an <b>Astable Multivibrator</b> and
</p><p>Generate <b>Gerber files</b>.
</p>

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To record this tutorial, we will use-
<p><b>Ubuntu Linux OS </b>16.04
</p><p><b>eSim </b>version 1.1.2
</p>

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To practice this tutorial, you should know to:
<p>Create a <b>Schematic</b> in <b>eSim</b>.
</p><p>Assign <b>components</b> to <b>footprints</b> and
</p><p>Set <b>design parameters</b> for <b>PCB layout</b>.
</p>

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If not, please see the prerequisite <b>eSim</b> tutorials on this website.

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Earlier in this series, we learnt how to
<p>Create a <b>Schematic</b> in <b>eSim</b>
</p><p>Map <b>footprints</b>
</p><p>Set <b>design parameters</b> for a <b>PCB </b>layout.
</p>

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I am going to reinforce the idea with the example of an <b>Astable Multivibrator</b>.

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Now watch me for the next one minute.

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A considerable part of this activity has been fast forwarded.

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I am adding <b>connectors</b> and mapping the <b>components</b> with their <b>footprints</b>.

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I have set the <b>design rules</b>, drawn the <b>board outline</b> and placed a few<b> tracks</b>.

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The partially made <b>layout</b> is available in the <b>Code files</b> link.

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Pause the video to download and extract the code files to your <b>Desktop.</b>

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We will use the downloaded code file to practice the rest of the tutorial.

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Now launch <b>eSim</b>.

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I have already opened <b>eSim</b>. Click on <b>Open Project </b>on the left toolbar.

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Browse to <b>Desktop</b>, click on <b>ASM underscore PCB</b>.  Then click on the <b>Open</b> button at the bottom right corner.

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Double-click on <b>ASM underscore PCB</b>.

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Click on <b>Open Schematic</b> button on the left toolbar.

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The <b>schematic</b> for <b>Astable Multivibrator</b> opens up.

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Click on <b>PCB new Tool </b>in the top toolbar.

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<b>Pcbnew Layout Editor</b> window opens up.

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I have already placed <b>tracks</b> for most of the <b>airwires</b>.

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Now, let us see how to convert the remaining <b>airwires</b> into <b>tracks.</b>

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Under the <b>Layer</b> tab on the right side of the <b>Pcbnew window, </b>click once on<b> B.Cu</b>.

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Click on <b>Place </b>button in the top toolbar and then select <b>Track </b>from the menu.

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Zoom into the <b>Layout editor</b> using the <b>F1</b> key.

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This can also be done using the scroll key of the mouse.

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Let us now place <b>tracks</b> for connecting <b>capacitor C1</b> to <b>LED1.</b>

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Click on <b>node 1 </b>of<b> C1.</b>

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And drag the cursor to <b>node 2 </b>of<b> LED1.</b>

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Double-click on<b> node 2</b> of <b>LED1 </b>to complete the <b>track</b>.

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Press <b>ESC</b> key.  Now let us place a <b>ground plane</b> to connect all the <b>ground nodes</b>.

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Click on the<b> Add filled zones</b> button on the right of the <b>Pcbnew window.</b>

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Click once, slightly above the top-left corner of the <b>board outline</b>.

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Now, let’s place the <b>ground plane</b> on the <b>Bottom Copper layer</b>.

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To do so, click on <b>B.Cu</b> under<b> Layer </b>column.

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Then click on <b>GND</b> under<b> Net </b>column.

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Click on the <b>OK </b>button at the bottom right corner of the <b>Copper Zone Properties </b>window.

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Drag the cursor with the pencil icon horizontally towards the right.

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Click once, slightly above the top-right vertex of the <b>outline</b>.

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Let us move this cursor vertically, towards the bottom-right vertex of the <b>board</b>.

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Click once slightly below the bottom-right vertex.

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We shall now finish drawing a rectangular <b>ground plane outline</b>.

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Note that we have to double-click to finish the rectangular <b>ground plane outline</b>.

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I have finished the <b>ground plane outline.</b>

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Note that we have to ensure that the<b> ground plane outline</b> lies outside the<b> board outline</b>.

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Right-click inside the <b>board outline</b>.

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Click on <b>Fill or Refill all zones </b>button from the drop-down menu.

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We have successfully added a <b>ground plane</b> to the <b>board</b>.

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Press <b>Esc</b> key to exit the <b>Add filled zones </b>tool.

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Let us now perform <b>Design Rule Check</b> i.e <b>DRC</b>, for the <b>layout</b> we created.

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Click on <b>Perform Design Rules check </b>present at the top of the <b>Pcbnew</b> toolbar.

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Click on <b>Start DRC. </b>

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This checks if any <b>design element</b> violates the <b>design parameters </b>set earlier.

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I have no errors in my design.

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Click the <b>OK</b> button at the bottom right corner, to exit the <b>DRC Control </b>window.

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Let us press <b>Ctrl </b>and <b>S </b>keys together to save our work.

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We will now create <b>gerber files</b> for this <b>board</b>.

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Click on the <b>Plot </b>button at the top of the <b>Pcbnew</b> toolbar.

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Let us select the <b>layers</b>.

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Click on the tab below <b>Plot format</b> and select <b>Gerber </b>out of the 6 options.

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Let us select the<b> layers</b> for which we want the <b>gerber files</b>.

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I will select <b>B.Cu, F.Silks </b>and<b> Edge.Cuts </b>by clicking on the boxes to the left.

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Click on the <b>Browse </b>button at the top right corner of <b>Plot </b>window.

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Let us navigate to the desired <b>directory</b> where we wish to save the <b>gerber files</b>.

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Click on the <b>Desktop</b>.  Double-click on <b>ASM underscore PCB.</b>

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Now click on the <b>Open </b>button at the bottom right of the <b>Select Output Directory </b>window.

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Click on <b>No </b>button in the <b>Plot Output Directory </b>window.

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Now click on the <b>Plot </b>button at the bottom of the <b>Plot </b>window.

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Acknowledgement messages will appear in the <b>Messages</b> window.

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Now, let us generate the <b>drill file</b> in <b>gerber format</b> for our designed <b>board</b>.

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Click on <b>Generate Drill File </b>at the bottom of the <b>Plot </b>window.

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Select the <b>Millimeters </b>option from the <b>Drill Units</b> section.

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Select the <b>Gerber </b>option under the <b>Drill Map File Format</b> section, if not selected.

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Select the <b>Absolute </b>option from the <b>Drill Origin</b> section, if not selected.

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We will leave the rest of the settings as they are.

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Click the <b>Drill File </b>option at the right of the <b>Drill Files Generation </b>window.

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An acknowledgement message will appear in the <b>Messages </b>window.

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Click on the <b>Close </b>button of the <b>Drill Files Generation </b>window.

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Click the<b> Close </b>button at the bottom right corner of the <b>Plot </b>window.

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Let us save our work by pressing <b>Ctrl</b> and <b>S</b> keys simultaneously.

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Now we will view the <b>gerber files </b>created.

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Open the <b>terminal</b> by pressing <b>Ctrl, Alt </b>and<b> T </b>keys together.

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Type <b>gerbview</b> and press the <b>Enter </b>key.

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Click on <b>File </b>at the top left corner, and select <b>Load Gerber File </b>option.

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Let us browse to the <b>directory</b> where we had saved our <b>gerber files</b>.

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I will click on <b>Desktop</b>.  Then double-click on<b> ASM underscore PCB.</b>

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Press <b>Ctrl </b>and <b>A </b>keys simultaneously to select all the <b>gerber files</b>.

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Click on the <b>Open </b>button at the bottom right corner of the <b>Open Gerber file </b>window.

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We can see the <b>PCB Layout </b>that we created in <b>Gerber format</b>.

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Let us summarize.

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In this tutorial, we learnt to-
<p>Create a <b>PCB layout</b> for an <b>Astable Multivibrator</b>.
</p><p>Generate <b>Gerber files</b>.
</p>

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Please post your timed queries in this forum.

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Please post your general queries on eSim in this forum.

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<b>FOSSEE</b> team coordinates the <b>Lab Migration</b> project.

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<b>FOSSEE</b> team coordinates the <b>Circuit Simulation Project</b>.

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Spoken Tutorial Project is funded by NMEICT, MHRD, Govt. of India. For more details, visit this website.

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This is Saurabh from IIT Bombay, signing off. Thank you.

