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Time Narration
00:01 Welcome to the spoken tutorial on “PCB Layout for Astable Multivibrator”.
00:07 In this tutorial, we will learn to -

Create a PCB layout for an Astable Multivibrator and

Generate Gerber files.

00:18 To record this tutorial, we will use-

Ubuntu Linux OS 16.04

eSim version 1.1.2

00:29 To practice this tutorial, you should know to:

Create a Schematic in eSim.

Assign components to footprints and

Set design parameters for PCB layout.

00:43 If not, please see the prerequisite eSim tutorials on this website.
00:48 Earlier in this series, we learnt how to

Create a Schematic in eSim

Map footprints

Set design parameters for a PCB layout.

01:01 I am going to reinforce the idea with the example of an Astable Multivibrator.
01:07 Now watch me for the next one minute.
01:11 A considerable part of this activity has been fast forwarded.
01:16 I am adding connectors and mapping the components with their footprints.
03:29 I have set the design rules, drawn the board outline and placed a few tracks.
03:36 The partially made layout is available in the Code files link.
03:41 Pause the video to download and extract the code files to your Desktop.
03:47 We will use the downloaded code file to practice the rest of the tutorial.
03:52 Now launch eSim.
03:55 I have already opened eSim. Click on Open Project on the left toolbar.
04:02 Browse to Desktop, click on ASM underscore PCB. Then click on the Open button at the bottom right corner.
04:12 Double-click on ASM underscore PCB.
04:16 Click on Open Schematic button on the left toolbar.
04:22 The schematic for Astable Multivibrator opens up.
04:26 Click on PCB new Tool in the top toolbar.
04:31 Pcbnew Layout Editor window opens up.
04:35 I have already placed tracks for most of the airwires.
04:40 Now, let us see how to convert the remaining airwires into tracks.
04:46 Under the Layer tab on the right side of the Pcbnew window, click once on B.Cu.
04:53 Click on Place button in the top toolbar and then select Track from the menu.
05:01 Zoom into the Layout editor using the F1 key.
05:05 This can also be done using the scroll key of the mouse.
05:10 Let us now place tracks for connecting capacitor C1 to LED1.
05:16 Click on node 1 of C1.
05:21 And drag the cursor to node 2 of LED1.
05:25 Double-click on node 2 of LED1 to complete the track.
05:31 Press ESC key. Now let us place a ground plane to connect all the ground nodes.
05:39 Click on the Add filled zones button on the right of the Pcbnew window.
05:45 Click once, slightly above the top-left corner of the board outline.
05:52 Now, let’s place the ground plane on the Bottom Copper layer.
05:56 To do so, click on B.Cu under Layer column.
06:02 Then click on GND under Net column.
06:07 Click on the OK button at the bottom right corner of the Copper Zone Properties window.
06:14 Drag the cursor with the pencil icon horizontally towards the right.
06:20 Click once, slightly above the top-right vertex of the outline.
06:26 Let us move this cursor vertically, towards the bottom-right vertex of the board.
06:32 Click once slightly below the bottom-right vertex.
06:36 We shall now finish drawing a rectangular ground plane outline.
06:42 Note that we have to double-click to finish the rectangular ground plane outline.
06:48 I have finished the ground plane outline.
06:51 Note that we have to ensure that the ground plane outline lies outside the board outline.
06:59 Right-click inside the board outline.
07:03 Click on Fill or Refill all zones button from the drop-down menu.
07:09 We have successfully added a ground plane to the board.
07:14 Press Esc key to exit the Add filled zones tool.
07:19 Let us now perform Design Rule Check i.e DRC, for the layout we created.
07:26 Click on Perform Design Rules check present at the top of the Pcbnew toolbar.
07:33 Click on Start DRC.
07:37 This checks if any design element violates the design parameters set earlier.
07:44 I have no errors in my design.
07:48 Click the OK button at the bottom right corner, to exit the DRC Control window.
07:55 Let us press Ctrl and S keys together to save our work.
08:01 We will now create gerber files for this board.
08:05 Click on the Plot button at the top of the Pcbnew toolbar.
08:10 Let us select the layers.
08:13 Click on the tab below Plot format and select Gerber out of the 6 options.
08:20 Let us select the layers for which we want the gerber files.
08:25 I will select B.Cu, F.Silks and Edge.Cuts by clicking on the boxes to the left.
08:37 Click on the Browse button at the top right corner of Plot window.
08:42 Let us navigate to the desired directory where we wish to save the gerber files.
08:47 Click on the Desktop. Double-click on ASM underscore PCB.
08:53 Now click on the Open button at the bottom right of the Select Output Directory window.
09:00 Click on No button in the Plot Output Directory window.
09:05 Now click on the Plot button at the bottom of the Plot window.
09:10 Acknowledgement messages will appear in the Messages window.
09:14 Now, let us generate the drill file in gerber format for our designed board.
09:19 Click on Generate Drill File at the bottom of the Plot window.
09:24 Select the Millimeters option from the Drill Units section.
09:29 Select the Gerber option under the Drill Map File Format section, if not selected.
09:37 Select the Absolute option from the Drill Origin section, if not selected.
09:43 We will leave the rest of the settings as they are.
09:47 Click the Drill File option at the right of the Drill Files Generation window.
09:53 An acknowledgement message will appear in the Messages window.
09:58 Click on the Close button of the Drill Files Generation window.
10:04 Click the Close button at the bottom right corner of the Plot window.
10:09 Let us save our work by pressing Ctrl and S keys simultaneously.
10:16 Now we will view the gerber files created.
10:20 Open the terminal by pressing Ctrl, Alt and T keys together.
10:26 Type gerbview and press the Enter key.
10:31 Click on File at the top left corner, and select Load Gerber File option.
10:39 Let us browse to the directory where we had saved our gerber files.
10:44 I will click on Desktop. Then double-click on ASM underscore PCB.
10:52 Press Ctrl and A keys simultaneously to select all the gerber files.
10:59 Click on the Open button at the bottom right corner of the Open Gerber file window.
11:05 We can see the PCB Layout that we created in Gerber format.
11:11 Let us summarize.
11:13 In this tutorial, we learnt to-

Create a PCB layout for an Astable Multivibrator.

Generate Gerber files.

11:23 Please post your timed queries in this forum.
11:27 Please post your general queries on eSim in this forum.
11:32 FOSSEE team coordinates the Lab Migration project.
11:36 FOSSEE team coordinates the Circuit Simulation Project.
11:41 Spoken Tutorial Project is funded by NMEICT, MHRD, Govt. of India. For more details, visit this website.
11:48 This is Saurabh from IIT Bombay, signing off. Thank you.

Contributors and Content Editors

Pratik kamble