7. Electronics design¶

Week Assignment

Group assignment: - Use the test equipment in your lab to observe the operation of a microcontroller circuit board (as a minimum, you should demonstrate the use of a multimeter and oscilloscope)

Document your work on the group work page and reflect what you learned on your individual page

Individual assignment: - Use an EDA tool to design a development board that uses parts from the inventory to interact and communicate with an embedded microcontroller

Learning outcomes - Select and use software for circuit board design

Demonstrate workflows used in circuit board design

Have you answered these questions?

Linked to the group assignment page
Documented what you have learned in electronics design
Checked your board can be fabricated
Explained problems and how you fixed them.
Included original design files (Eagle, KiCad, etc.)
Included a hero shot

Group assignment

A full description of the group assignment was done at yufablab

Here my key takeouts: In group assignment on Electronic Design, our main focus was to build confidence in measurement-based troubleshooting through hands-on experiments. We worked through three practical blocks: (1) voltage and current measurement, (2) oscilloscope-based signal measurement using a brushless motor setup, and (3) logic analyzer signal capture and interpretation.

The core outcome for us was moving from assumptions (“it should work”) to evidence (“we measured it and can explain it”), and documenting results in a clear, repeatable way.

For voltage and current measurement, we used a bench power supply and a multimeter to verify real electrical values on a simple circuit (for example, an LED with a current-limiting resistor). We measured voltage in parallel across the component and measured current in series by inserting the multimeter into the circuit path. Personally, this part helped me internalize the difference between what the power supply is set to and what the circuit actually experiences under load, and it reinforced why correct meter connection matters for both safety and accurate readings.

For signal measurement, we used an oscilloscope to observe the control signals in a brushless motor experiment, paying attention to waveform shape, frequency, duty cycle, and stability. Then we used a logic analyzer to capture and inspect digital signal transitions over time, which made timing relationships and control sequences much clearer. For me, combining these two tools was the biggest takeaway: the oscilloscope helped me judge signal quality in “analog detail,” while the logic analyzer helped me verify digital timing and structure—together giving a complete picture of how the system behaves.

Electronic Circuit Components¶

Electronic Design Content has the following major three parts: components, circuit and simulation. We are lucky to know more about components and circuit with great and simple practical online tools.

Before jumping to the Electrical Design, it is quite important to have substantial understanding of Electric Circuit Theory and Electromagnetic Theory as they form the foundation of all branches of electrical engineering. Fields such as power systems, electronics, control, communications, and instrumentation rely heavily on circuit theory. An electric circuit is an interconnection of electrical elements designed to transfer energy from one point to another. Electric circuits are used in numerous electrical systems to accomplish different tasks.

Each electric circuit has a electric charge, is an electrical property of the atomic particles of which matter consists, measured in coulombs (C). A unique feature of electric charge or electricity is the fact that it is mobile; that is, it can be transferred from one place to another, where it can be converted to another form of energy.

Electric current is the time rate of change of charge, measured in amperes (A), so 1 ampere is equal to 1 coulomb/ 1second

If the current does not change with time, but remains constant, we call it a direct current (dc). An alternating current (ac) is a current that varies sinusoidally with time. The direction of current flow is conventionally taken as the direction of positive charge movement (from – to +).

Voltage (or potential difference) is the energy required to move a unit charge through an element, measured in volts (V). 1 volt is equal to 1 joule/coulomb or equal to 1 newton-meter/coulomb. Current and voltage are the two basic variables in electric circuits, but they are not sufficient by themselves, so we need to know how much power an electric device can handle or the electric energy consumed over a certain period of time. p = vi

Some common prefixes used in electronics

Key Definitions¶

Components

Ribbon Cable - A flat, multi-wire cable used for making multiple connections simultaneously, commonly used in data and signal transmission.
IDC Connector- (Insulation Displacement Connector) Designed to attach directly to ribbon cables without the need for soldering, making it easy to connect multiple wires at once.
Button - A simple mechanical switch that momentarily connects or disconnects a circuit when pressed, often used for user inputs.
Switch - A device that controls the flow of electricity by opening or closing a circuit. It can be toggle-based (on/off) or momentary like a push button.
Resistor - A passive component that limits electrical current in a circuit, following Ohm’s Law (I = V/R). Different resistance values are used to regulate voltage and current in various applications.
Capacitor - A component that stores and releases electrical energy, playing a key role in filtering, power supply stabilization, and signal processing.
Formulae: C = Q/V, I = C dV/dt
Unpolarized- Can be connected in any orientation, used in AC circuits.
Polarized - Electrolytic capacitors with marked polarity, commonly used in power supply circuits.
Crystal / Resonator - Used for generating stable clock signals in microcontrollers and other timing applications, ensuring precise operation.
Inductor - A coil of wire that stores energy in a magnetic field, commonly used in filters, transformers, and power electronics.
Formula: V = L dI/dt (Voltage across an inductor is proportional to the rate of change of current).
Diode - A semiconductor device that allows current to flow in only one direction, protecting circuits from reverse voltage.
PN Junction Diode - Standard rectifier for converting AC to DC.
Schottky Diode - Fast-switching, low forward voltage drop, used in power applications.
Z- ener Diode - Allows reverse conduction at a specific voltage, used for voltage regulation.
LED (Light-Emitting Diode) - Converts electrical energy into light, widely used for indicators and displays.
Transistor - A semiconductor device used as a switch or amplifier.
Bipolar Junction Transistor (BJT) - A current-controlled device with three terminals: collector, emitter, and base, used for amplification and switching.
MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) - A voltage-controlled device with three terminals: source, drain, and gate, used in power electronics and digital circuits.
Battery, Regulator, DC-DC Converter - Power sources and voltage regulators that supply stable voltage levels to electronic circuits.
Op-Amp (Operational Amplifier) - A high-gain voltage amplifier used in analog circuits for signal amplification, filtering, and mathematical operations.
Key functions: Differential amplifier, negative feedback, voltage gain, buffer (follower), transimpedance, transconductance.
Microcontroller (MCU) - A small computer on a single chip with integrated peripherals like GPIO (General Purpose Input/Output), I2C, SPI, ADC (Analog-to-Digital Converter), and PWM. Used in embedded systems, automation, and control applications.
Sensors - Devices that detect physical parameters such as temperature, light, pressure, motion, or proximity, converting them into electrical signals.
Actuators - Components that convert electrical signals into mechanical movement, such as motors, solenoids, and relays.

Circuits

Current (A) & Voltage (V)-
Electrical flow is often compared to water in pipes:
- Current (A) - The amount of electrons flowing through a wire, similar to the volume of water flowing in a pipe.
- Voltage (V) - The electrical potential difference, similar to water pressure.
Power is calculated using: P = I²R = IV (Power = Current² x Resistance = Voltage x Current).
Kirchhoff’s Laws -
Kirchhoff’s Current Law (KCL) - The sum of currents entering a node equals the sum of currents leaving it.
Kirchhoff’s Voltage Law (KVL) - The total voltage around a closed loop equals zero, meaning energy is conserved.
EDA (Electronic Design Automation) - The process of designing PCBs (Printed Circuit Boards) using specialized software.
Steps: Sketching, schematic design, component (auto)placement, (auto)routing, simulation, and fabrication.
Design Elements:
Layers – Multiple copper layers for signal routing.
Angles – Proper routing angles to minimize signal interference.
Vias – Holes connecting different PCB layers.
Power Planes & Ground Pours – Large copper areas for efficient power and ground distribution.

Test Equipment

Regulated Power Supply - Provides adjustable voltage and current with protection features, ensuring stable power for circuit testing.
Multimeter - A handheld tool for measuring voltage, current, and resistance, essential for troubleshooting circuits.
Oscilloscope - Displays electrical signals in a time-dependent manner, helping analyze waveforms, frequencies, and signal integrity.
Logic Analyzer - Captures and analyzes digital signals in microcontrollers, FPGAs, and communication protocols like SPI, I2C, and UART.
Mixed Signal Analyzer- Combines oscilloscope and logic analyzer functions for debugging both analog and digital signals.
Multichannel Analyzer - Used for observing multiple signals simultaneously, essential for complex systems.

Circuit Elements. There are two types of elements found in electric circuits: passive elements (resistors, capacitors, and inductors) and active elements (generators, batteries, and operational amplifiers). An active element is capable of generating energy while a passive element is not. The most important active elements are voltage or current sources that generally deliver power to the circuit connected to them. There are two kinds of sources: independent and dependent sources.

Common resistor types

Common potentiometer styles

Circuit Exercises¶

Circuit exercise will be fun with these tools as they have real-time simulation.

It is better to start with

EVERYCIRCUIT EXERCISES¶

EVERYCIRCUIT has easy to use interface that allows immediately to create simple curcuit. ir oder to create first circuit, click new circuit on the top right panel and then components can be added by arrow click.

Added electronic components can be connected and changed to create circuit by using panel on bottom left.

After wiring together all components, circuit can be cimulated by clicking yellow button.

EVERYCIRCUIT provides printscreen of simulated circuit in back and white background color image.

This is the first example of simple circuit containing voltage supply source and a lampe.

This circuit demaonstrates series connection type of lamps, which shows change of voltage at each lampe.

This circuit demonstrates parallell connection of lamps.

The following three circuits demonstrate gradual volume change of resistor.

The following two circuits show the serial and parralel connection of resistors.

The circuit displays voltage divider.

FALSTAD EXERCISES¶

The Falstad has similar simulation characteristics, but it provides more built-in simaltion examples for circuit components located in the CIRCUITS panel.

Resistor

Capacitor

Inductor

LRC Circuit

Diodes

Half-Wave Rectifier and Full-Wave Rectifier

Zener Diodes

N-P-N Transistor and P-N- P Transistor

N-MOSFET and P-MOSFET

TINKERCAD EXERCISES¶

KICAD EXERCISES¶

Installation of KiCad 8 and integration of Fab Libriaries

Design Rules – according to docs.kicad.org¶

When designing a PCB, it’s essential to define proper design rules, especially when using specific milling tools. Since I use a 0.4mm end mill bit for cutting traces and a 0.8mm end mill bit for the board outline, I make sure to leave enough clearance between traces, pads, and the board edge to ensure clean milling and prevent unintended shorts.

Setting Up Design Rules in KiCad¶

Access the Board Setup:
- Open File > Board Setup… to configure the PCB layout parameters.
Configure Constraints
- Under Design Rules > Constraints, I define critical design parameters like minimum track width, clearance, and via sizes.
- For my setup:
  - Clearance: I set the minimum clearance to at least 0.4mm to match the smallest milling bit size.
  - Edge Clearance: Ensuring at least 0.4mm distance between traces and the board outline prevents the 0.8mm milling bit from cutting into copper traces.
Define Net Classes
- Under Design Rules > Net Classes, I assign different clearance and width settings based on signal requirements.
- Power traces often require wider tracks to handle higher currents, while signal traces can be narrower.

Verifying Design with Design Rule Checker (DRC)¶

After setting up the design rules and completing the PCB layout, I always verify my design to ensure it follows the constraints.

Run the DRC
- Open Inspect > Design Rules Checker and run a full check.
Configure DRC Settings
- Enable options like:
  - Refill all zones before performing DRC – Ensures copper zones are properly updated.
  - Report all errors for each track – Helps in pinpointing clearance issues.
Review Violations
If any violations are detected, they are listed in the DRC results. Clicking on them highlights the problematic areas, making it easy to correct the design.

By carefully setting up these rules and running the DRC before manufacturing, I ensure that my PCBs are error-free, easy to mill, and optimized for reliable performance.

Fab Electronics Library Installation for KiCad¶

I use KiCad 8 for my electronic design work, ensuring compatibility with the latest libraries and tools, as maintaining updates is crucial for efficiency. Since the library is constantly evolving, I recomend to pull the latest version before starting a project to avoid inconsistencies.

Installation of KiCad 8 and integration of Fab Libriaries to it¶

:memo: fab Installation instruction

Clone or download this repository. You should rename the directory to fab.

Store it in a safe place such as ~/kicad/libraries or C:/kicad/libraries.

Run KiCad or open a KiCad .pro file.

Go to “Preferences / Configure Paths” and add new environment variable “FAB” that points to location of the fab library on your drive, e.g. ~/kicad/libraries/fab. This is needed for the 3D models to load correctly.

Go to “Preferences / Manage Symbol Libraries” and add fab.kicad_sym as symbol library.

Go to “Preferences / Manage Footprint Libraries” and add fab.pretty as footprint library. KiCad Library Utils

Circuit Design for ATtiny412_SSFR¶

Here, I watched clip from Adrian Torres which gives a brief and simple tutorial on creating a PCB board design in KiCAD 7.0, specifically with an ATTiny412 microcontroller to attempt to learn PCB board designing .

Understanding the Basics of Schematic Design My learning journey began with understanding how to design a basic schematic using KiCad. I followed a tutorial to create a simple ATtiny412 circuit, which includes:

A microcontroller (ATtiny412) A 3-pin UPDI programming header A power decoupling capacitor (C1) An LED indicator with a current-limiting resistor (R1, 1kΩ) While creating the schematic, I learned about:

✅ Proper power (VCC) and ground (GND) connections
✅ Assigning functional pins like UPDI, TXD, and RXD
✅ Labeling signals and ensuring clear wiring

I also realized the importance of a pull-up resistor on UPDI for stable programming, which I initially overlooked.

Translating the Schematic to a PCB Layout After finalizing the schematic, I moved on to the PCB layout phase. This step involved:

Placing components efficiently to minimize trace lengths Routing connections to ensure proper electrical functionality Ensuring proper clearance and alignment for manufacturability Through multiple iterations, I observed:

✅ The importance of compact layout design for efficiency
✅ The need to adjust silkscreen labels for readability
✅ How trace widths affect power delivery and signal integrity

I also had to troubleshoot unrouted airwires, ensuring all required connections were complete.

Optimizing the PCB Design As I refined my PCB layout, I learned several best practices:

Using a ground plane instead of individual GND traces for better noise reduction Avoiding overlapping silkscreen text for clearer labeling Optimizing pad spacing to prevent soldering issues After implementing these improvements, I generated the 3D PCB model to visualize the final design.

Key Takeaways and Challenges 🚀 What I Achieved:

✔️ Successfully designed a working ATtiny412-based PCB ✔️ Learned schematic design, component placement, and PCB routing ✔️ Understood the importance of signal integrity and power management

Challenges Faced:

Initial routing mistakes that led to missing connections Component misalignment that needed fixing Refining silkscreen text placement for readability Overall, this learning experience gave me a strong foundation in PCB design, and I now feel more confident in creating custom circuit boards! I created the PCB board schematic shown below:

Circuit Design for ESP32-WROOM-32U¶

Process Demonstration

In schematic part, we picked up the Microcontroller, ESP32-WROOM-32U , boot/reset control, a UART header for programming, a few GPIO break-outs, and three indicator LEDs around it. Two LEDs (L1, L2) each have a series resistor (R1, R2, 1206 package). Headers labeled SV1 / SV2 / SV3 break out several GPIO pins (e.g., IO1…IO10 etc.) plus power/ground for hooking up sensors/actuators.

This PCB places an ESP32-S3 module in the center with a large ground/thermal pad, surrounded by BOOT/RESET switches at the top, two LED-resistor pairs at the bottom, and a 1×6 FTDI/UART header on the right.

Circuit Design for ESP32-C3-02 Sensor Board of the Final Project ¶

Learning outcomes¶

For Electronics Design, I started by reviewing key terminology—components (resistors, capacitors, diodes, regulators, MCUs), common circuit blocks (power regulation, clock/reset, I/O protection), and the test equipment used to validate them (multimeter, oscilloscope, logic analyzer, PSU). I then installed KiCad 8 and integrated the Fab libraries, confirming symbol/footprint mapping and setting project-wide DRC rules and net classes. With the toolchain ready, I designed an ATtiny412_SSFR board: captured the schematic (USB-to-UPDI header, power input and decoupling, reset/UPDI pullups), assigned verified footprints, and added labels for clean net routing. PCB layout focused on short return paths, decoupler placement near VCC/GND, clear silkscreen, mounting holes, and a sane stack-up/copper weight. After running ERC/DRC, I generated Gerbers, drill, and pick-and-place files and prepared a short bring-up plan (continuity checks, power-on current, UPDI flash, LED blink). This workflow connected theory to practice and produced a manufacturable microcontroller board ready for fabrication and testing.