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Shown to the right is an exposition to electrical design, and should clarify a few fundamental points which outline the electrical design process. For starters, it will illustrate a few of the building blocks of electricity (voltage, current, resistance), as well as delve into the purpose of the different processes which go into a finished electrical circuit. It will showcase an array of component symbols which you may encounter, and provide information about the purpose of each one, and then it will tell you how to access the documentation required for this Fabrication Night.
Note: This presentation should be given by the Team Lead as people transition into the workshop. It should serve as a jumping-off-point, and contains helpful information in the 'Speaker Notes'
The following video delves into the basics of design in EasyEDA (including the schematic design and PCB layout tools).
Here is a roadmap of the 'big picture' steps of the Schematic Design process:
Make an EasyEDA account and access the Std. Edition 'Designer'
Navigate to the designer tabs
Select all needed components from the library
Re-orient and re-configure elements as needed
Wire connections
EasyEDA Schematic Design - Video Tutorial (3:29 - 16:33)
EasyEDA Schematic Design - Video Tutorial (3:29 - 16:33)
Using this video, I have developed a guided walkthrough of the Schematic Design process.
'Schematic Design' Section Deliverable
'Schematic Design' Section Deliverable
After following along with either the video above or the guided walkthrough below, you should have a schematic that looks like the following:
Making an EasyEDA Account and Accessing Std. Edition 'Designer
Making an EasyEDA Account and Accessing Std. Edition 'Designer
First, navigate to the EasyEDA Website (easyeda.com) and press the 'Login' button at the top right corner.
Sign in with your UNCA Google Account
Once logged in, press the 'Design Online' button and select 'Std. Edition'
Navigating to the Design Tabs
Navigating to the Design Tabs
After opening the Std. Designer, your screen should look like this. Your 'Projects' tab is probably not populated, but we'll start on that now!
From the upper 'File' menu, pass your mouse over the 'New' menu and select 'Project'.
Name this project whatever you'd like, and if it's helpful, you can add a description. The 'Title' is what will show up under the folder with your username in the side 'Projects' panel.
As soon as you press the 'Save' button, a new schematic populates under your project. Open the 'File' menu and press 'Save' to build the habit.
Right now, the organizational information is pretty generic. This can be helpful to update so that your documentation is easier for others to sort through. If you'd like to customize it, double-tap the blue text in each section.
This will open a text-box where you can rename the section. When you're finished, press 'return'.
Now, navigate to the 'Commonly Library' panel on the left side. We are ready to place the elements that we need!
Selecting All Necessary Components from the Library
Selecting All Necessary Components from the Library
For this schematic, these are the elements that we will be using. None are customized, so all of them can be accessed from the 'Commonly Library'.
NOTE: There is one element attached to C3 in the final schematic (shown in a grey text-box at the beginning of this page) which is not depicted here. This will be addressed in a later section!
From Top to Bottom & Left to Right, the component list is as follows:
2 Voltage Common Collectors (VCC's), 2 Common Grounds, 4 Resistors, 3 Capacitors (Non-Polarized), 1 Battery, 1 Button, and 2 Transistors.
To add components to your sheet, click on the picture-representation that matches what is on your component list (ex. Common Ground). Then, move your mouse to the your sheet on the right. Click your mouse to place the component.
As long as it's selected on the left panel, you can place as many of these components as you'd like. When you're done, you can either press 'esc' on your keyboard or press on another component in the library.
NOTE: The software will not let you drag components onto your sheet, make sure that you're not holding down the mouse as you're going between the panel and schematic.
Changing the Orientation of Selected Elements
Changing the Orientation of Selected Elements
When you pull components from the library, they will be oriented exactly as they appear in the panel. In some cases, this works perfectly! For our schematic, though we need to re-orient some of them. For starters, we should change the direction of the resistors from horizontal to vertical.
Use your mouse to click and drag a box around all four resistors to select them. They should highlight red.
NOTE: If your elements are configured like those above, consider moving the resistors away from your other elements by dragging one of the picture-representations (which, if all four are selected, will move them at the same time) to the right as shown in the next step.
Next, we are going to use a hotkey to rotate them. Press the 'spacebar' on your keyboard, and they should rotate. This will change their orientation from horizontal to vertical.
NOTE: Because resistors aren't polarized, you can rotate them once, three times, five times, etc. and it will not change the functionality of the element. For elements such as diodes, polarized capacitors, or other things that are functionally asymmetrical, make sure to pay attention to the direction your inputs and outputs are facing!
Now to reconfigure our resistors to match the specifications of our final schematic (shown in a grey text-box at the beginning of this page). First, select the resistor labeled 'R1' by clicking it once. A panel should open on the right-hand side called 'Objects Properties'. In the 'Name' section, change the value from '1k' to '22k'.
We can accomplish the same thing by double-clicking the blue text that says '1k' on the element and changing the information inside of the textbox.
Change the following values using either method:
R1 = 22k R2 = 22k
R3 = 150k R4 = 220k
Next, we need to change the orientation of the transistors. If you forget the hotkeys, don't worry! You can also rotate any component from the 'Format' menu, just click 'Rotate Left' or 'Rotate Right'.
Whichever way you choose, you'll have to rotate twice (180º) for our purposes.
But we aren't finished yet! This is one of those cases where our element is functionally asymmetrical. We want the emitter side of one of our transistors to be on the bottom of the component. To do this, select one of the components. Then, you can either use the 'Y' hotkey or go to the 'Format' menu and press 'Flip Vertical'.
Now, we are going to move our components to a position that looks something like our final schematic (shown in a grey text-box at the beginning of this page).
You may have encountered this if you chose to move your resistors, but this software has two different movement options that you should be aware of. If you select the picture-representation of the element before you drag, you will take both the name and the component with you.
Alternatively, if you only select the name of the element, you'll notice that the text is the only thing that you take with you.
There are certainly applications for this, but for our purposes, it's better to treat the symbol and text as a package-deal. Make sure that as you're moving things around, you are selecting and repositioning the symbol!
Your sheet should end up looking similar to the one shown on the left. This definitely isn't something that you need to be counting grid-lines for, though! The goal of repositioning in this step is to:
Separate the two subcircuits
Have a general roadmap for when we add wires
In my walkthrough, the positions of these elements change as I wire them. Finishing this step doesn't mean that you have to have the perfect setup, so don't get lost in making everything line up correctly!
Wiring Connections Between Elements
Wiring Connections Between Elements
At the top of the Schematic Window, the 'Wiring Tools' collapsible toolbar is how we will wire our connections.
For the first step, we will either select 'Wire' from the toolbar, or press the 'W' hotkey on our keyboard.
Now, click on the the upper terminal of 'R1' to place a wire which starts there.
For this connection, click on 'R2'. This wires the upper terminal of 'R1' to 'R2'.
NOTE: Even though the upper terminals of 'R1', 'R2', 'R3', and 'R4' are all on the same gridlines, you won't have any success if you try to wire 'R1' to 'R4' with the intention of connecting the whole line. In this software, you have to intentionally map all of your connections.
Wire a line which has connections at 'VCC' and the upper terminals of 'R1', 'R2', 'R3', and 'R4'. You should have red points at 'R1', 'R2', and 'R3', which tell you that they are included in the wire.
Now, connect the bottom terminal of 'R1' to the leftmost terminal of 'C1', and then the rightmost terminal of 'C1' to the bottom terminal of 'R2'. Connect the 'C1' and 'R1' junction to the collector terminal of the 'Q2' transistor.
Mirror this setup on the right side of the schematic. Then, wire the emitter terminals of the transistor together and to common ground. Wire the 'C2', 'R4', and 'Q1' transistor junction to 'C3'.
Wire the base terminal of the 'Q1' transistor to the 'R3' and 'C2' junction. Then, Wire the base terminal of the 'Q2' transistor to the 'R2' and 'C1' junction. Lastly, wire the 'Q1' and 'Q2' junction to ground.
NOTE: You may notice that the 'Q2' transistor moved upwards in my schematic. This was done so that it would be easier to differentiate between the two groups of connections. In order to move an element that is already wired, you can click on its symbol to select it, and then drag it to a new location. The wires at its terminals will automatically adjust!
NOTE: Although it looks like there is a wire joining the base terminals of 'Q1' and 'Q2', they actually are not connected, but overlapping. You can verify this, as there is no red point at their intersection.
In our final schematic (shown in a grey text-box at the beginning of this page), there is an additional element that we have not yet accounted for. This is a probe which we can find in the 'Connecter' section of the 'Common Library' panel.
We waited to add it in to showcase another way to join our elements together! Select the port and place it so that the black terminal on the right is aligned with the rightmost terminal of C3. Press 'esc', and see that the two are now connected. You can verify this, as there is a grey point at their intersection. This appears when both terminals are directly connected without a wire.
NOTE: If you're unsure of this grey intersection, you can select the rightmost element's symbol, and then drag it to the right. A wire should appear!
Now, switch to your other sub-circuit. First, wire 'VCC' to the positive side of 'B1'.
NOTE: The positive side always has a longer line compared to the negative side.
Next, connect the negative (smaller-lined) side of 'B1' to terminal one of 'KEY1', and then connect terminal two of this device directly to ground.
NOTE: The 'KEY1' button is actually non-polarized, which means that you can connect the battery and ground to either the first or second terminal (as long as they're opposite each other).
And finally, we are finished with the Schematic Design process. At this point, we are prepared to represent our circuit on a PCB which will be covered in the next section.
For more detailed information on the in's and out's of EasyEDA, scroll through the following documentation:
EasyEDA-Tutorial_v6.4.32.pdfPage updated
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