Workshop 1 - Practice Exercises

Part 1: Circuit Simulation with EasyEDA ▶

EasyEDA Simulation

In this exercise, we will focus on EasyEDA's simulation. Watch these tutorials to get started:

▶ Simulation Tool Introduction

▶ EasyEDA Tutorial for Beginners

Getting Started with EasyEDA

Step 0: Access EasyEDA Editor

Go to https://easyeda.com/
Click on "Online Editor (Std Edition)" button
You'll be directed to the EasyEDA editor: https://easyeda.com/editor
Login or Register (free account)
You can now start creating schematics and simulating circuits!

How to Use EasyEDA Simulation

Step 1: Open Simulation

Open Project: File → Open (Ctrl+O) to browse saved or example projects

Open your schematic in EasyEDA
Click "Simulation" in top menu
Select "Spice Simulation"
Simulation window opens

Step 2: Add Components

Add a voltage source (Press V or from component library)
Add resistor, LED, or other components you want to test
Connect components with wires (Press W)
Add ground symbol (essential for simulation)
Set component values by double-clicking them
Note: To add ammeter (current meter), click on the meter component and select "Ammeter" - default is voltmeter

Step 3: Run Simulation

Click the voltage source and change default 1V to 5V
Click "Simulation" → "Run the Simulation" from the top menu
Or click "Run the Simulation" button or the play icon in the top menu
Choose simulation type (Transient)
Click "Run"

Exercise 1: RC Filters - Low-Pass and High-Pass

Exercise Goal

Build and test both low-pass and high-pass filters to understand frequency filtering.

What you'll learn:

Low-pass: Filter high frequencies from measurement signals (noise and interference) - most common with Arduino
High-pass: Block DC component from signal - especially useful in audio signal processing
Test how signal weakens at different frequency values
Calculate and verify cutoff frequency

Useful resources:

📝 Task: Design both low-pass and high-pass filters with cutoff frequency f_c = 1kHz. Test each filter by changing the input frequency to verify they work correctly.

Exercise 2: LED with Capacitor - Slow Fade Effect

Exercise Goal

Simulate the same LED + capacitor circuit you built in Workshop 0. Observe how the capacitor affects LED behavior when the switch is opened.

What you'll learn:

Capacitor stores energy and releases it slowly
LED fades out slowly instead of turning off instantly
Time constant τ = RC determines fade speed
Same phenomenon you saw in Workshop 0, now simulated!
Experiment: Try different settings to see the effect clearly

LED Fade Time Calculator

Time Constant Calculator

R (Ω): Ω

C (µF): µF

τ: 1 ms

LED Fade Time

V₀ (V): V

LED Threshold (V): V

τ (ms): ms

Glow Time: 1.1 ms

Exercise 3: RLC Resonance Circuit (Advanced)

Exercise Goal

Demonstrate voltage amplification at resonance: voltage across capacitor can be HIGHER than input voltage!

What you'll learn:

At resonance: V_capacitor > V_input (voltage gain without active components!)
Principle behind crystal radios (AM radio without batteries)
Applications: Crystal radio, tone selection in touch-tone phones

Learn more:

▶ YouTube - RLC Resonance Explained

RLC Resonance Calculator and Plotter

RLC Values

R (Ω):

L (µH):

C (pF):

Series RLC
Measure across C

Input Signal

Vin(AC):

Output

V_C at f₀: 6.3 V

f₀: 10.0 kHz

Q: 6.3

📻 Crystal Radio - Fun Fact

RLC resonance → crystal radio! Antenna → L-C resonance → diode → sound. No batteries needed!

▶ YouTube - Crystal Radio Tutorial

We won't go deeper here to prevent things from getting completely out of hand... 😅

Part 2: PCB Design Exercise ▶

EasyEDA Tutorial

Before diving into PCB (Printed Circuit Board) design, watch this tutorial to get familiar with EasyEDA:

▶ YouTube - EasyEDA Tutorial for Beginners

PCB Design Process

Designing a PCB involves several steps:

Schematic Design: Draw your circuit diagram
Component Selection: Choose parts with correct footprints
PCB Layout: Arrange components and route traces
Design Rule Check (DRC): Verify design is manufacturable
Generate Gerber Files: Files needed for manufacturing
Order PCBs: Send to manufacturer
Assembly: Solder components onto finished boards

Getting Started with EasyEDA

Go to https://easyeda.com/
Click "Sign Up" and create a free account
Log in and click "New Project"
Give your project a name (e.g., "NPN Amplifier")
Click "Create" to start

Follow the video tutorial for step-by-step instructions.

Step 1: Creating a Schematic

The schematic is a diagram showing how components are electrically connected.

1.1 Open Schematic Editor

In your project, click "New" → "Schematic"
You'll see a blank canvas with a toolbar on the left

1.2 Place Components

To add components:

Click the "Place" menu or press P
Select "Part..." or press Shift+P
Search for components (e.g., "BC547", "resistor", "capacitor")
Click to place on schematic

1.3 Connect Components with Wires

1.4 Set Component Values

Double-click on a component
Edit the "Value" field (e.g., "10k" for a resistor)
You can also edit the "Designator" (R1, R2, C1, etc.)
Click "OK" to save

Important Schematic Tips

Give every component a unique designator (R1, R2, C1, etc.)
Set values for all resistors and capacitors
Use net labels for connections that would otherwise need long wires
Add a title block with your name and date

Step 2: Converting to PCB

Once your schematic is complete, it's time to create the physical PCB layout.

2.1 Generate PCB and Set Board Outline

In the schematic editor, click "Design" → "Convert Schematic to PCB"
Or click the PCB icon in toolbar
A new PCB editor window opens with your components
Components will appear in a cluster with white "ratsnest" lines showing connections
Click "Board Outline" in the layers panel and draw a rectangle or custom shape

2.2 Arrange Components

Drag components to logical positions
Try to minimize crossing ratsnest lines
Group related components together
Keep input and output connectors on opposite sides
Leave space between components for routing

Step 3: Routing Traces

Routing is drawing the copper traces that connect your components.

3.1 Understanding Layers

Most simple PCBs are 2-layer:

Top Layer (red): Copper on top of board
Bottom Layer (blue): Copper on bottom of board
Via: A hole connecting top and bottom layers

3.2 Manual Routing

Select "Track" tool or press W
Click on a component pad to start
Route the trace to the destination pad
Double-click to finish the trace
Use vias to switch between layers if needed

Routing best practices:

Make power and ground traces wider (0.5-1mm)
Signal traces can be narrower (0.3-0.5mm)
Avoid sharp 90° angles - use 45° bends
Keep traces as short as possible

3.3 Auto-Router (Optional)

EasyEDA has an auto-router, but manual routing is better for learning:

Click "Auto Route" button
Configure settings (usually defaults are fine)
Click "Run"
Review and manually fix any poor routes

3.4 Ground Plane (Copper Pour)

Instead of routing ground traces, create a ground plane:

Click "Copper Area" tool
Select "GND" net
Draw around entire board outline
Set layer to "Bottom Layer"
Right-click → "Build Copper Area"

This provides excellent ground connection and reduces routing!

Note: This is not mandatory, but if the board is milled, it speeds up the work.

Step 4: Design Rule Check

Before manufacturing, verify your design meets manufacturing requirements.

Run DRC

Click "Design" → "Check DRC"
Fix any errors shown (red highlights)

Review the Board

Before creating Gerber files, carefully inspect the board:

Use 2D and 3D views

Step 5: Generating Gerber Files

Gerber files are the industry-standard format for PCB manufacturing.

Export Gerbers

Click "Fabrication" → "PCB Fabrication File (Gerber)"
Review settings (defaults usually fine)
Click "Generate Gerber"
Download the ZIP file

Step 6: Ordering PCBs

EasyEDA makes ordering incredibly easy!

Order from JLCPCB (Recommended)

In EasyEDA, click "Fabrication" → "Order at JLCPCB"
Your design is automatically uploaded
Select quantity (minimum usually 5 boards)
Choose PCB color (green is cheapest, but many colors available!)
Review price (typically $2-5 for small boards + shipping)
Add to cart and checkout
Delivery takes 1-2 weeks

Advanced Topics

Multi-Layer PCBs

For complex designs, use 4-layer boards:

Layer 1 (Top): Signal traces
Layer 2 (Inner): Ground plane
Layer 3 (Inner): Power plane
Layer 4 (Bottom): Signal traces

More expensive but much better for noise reduction.

SMD vs Through-Hole

Through-hole: Components have leads that go through holes (easier for beginners)
SMD (Surface Mount Device): Components soldered on surface (smaller, professional)

Start with through-hole, progress to SMD as you gain experience.

Workshop 1: Practice Exercises

About This Workshop

Table of Contents ▶

Part 1: Circuit Simulation with EasyEDA ▶

EasyEDA Simulation

Getting Started with EasyEDA

Step 0: Access EasyEDA Editor

How to Use EasyEDA Simulation

Step 1: Open Simulation

Step 2: Add Components

Step 3: Run Simulation

Exercise 1: RC Filters - Low-Pass and High-Pass

Exercise Goal

Exercise 2: LED with Capacitor - Slow Fade Effect

Exercise Goal

LED Fade Time Calculator

Time Constant Calculator

LED Fade Time

Exercise 3: RLC Resonance Circuit (Advanced)

Exercise Goal

RLC Resonance Calculator and Plotter

RLC Values

Input Signal

Output

📻 Crystal Radio - Fun Fact

RLC Frequency Response

Part 2: PCB Design Exercise ▶

EasyEDA Tutorial

PCB Design Process

Getting Started with EasyEDA

Step 1: Creating a Schematic

1.1 Open Schematic Editor

1.2 Place Components

1.3 Connect Components with Wires

1.4 Set Component Values

Important Schematic Tips

Step 2: Converting to PCB

2.1 Generate PCB and Set Board Outline

2.2 Arrange Components

Step 3: Routing Traces

3.1 Understanding Layers

3.2 Manual Routing

3.3 Auto-Router (Optional)

3.4 Ground Plane (Copper Pour)

Step 4: Design Rule Check

Run DRC

Review the Board

Step 5: Generating Gerber Files

Export Gerbers

Step 6: Ordering PCBs

Order from JLCPCB (Recommended)

Advanced Topics

Multi-Layer PCBs

SMD vs Through-Hole

Additional Resources