An Internship Report On

PCB DESIGN
An Internship report is submitted in partial fulfillment of the requirement for the
degree of
Bachelor of Technology
in

Electronics and Communication Engineering

Submitted By
GULLAPALLI LAKSHMI DHANUSHA
228867603031

Under the Esteemed Guidance of

Mrs. N. SANTOSHI, M. Tech
Assistant Professor
Dept of ECE AKNUCE, RAJAMAHENDRAVARAM.

DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING

ADIKAVI NANNAYA UNIVERSITY COLLEGE OF ENGINEERING
ADIKAVI NANNAYA UNIVERSITY, RAJAMAHENDRAVARAM, A.P.
RAJAMAHENDRAVARAM – 533296
A.Y:2024-2025

i
ADIKAVI NANNAYA UNIVERSITY COLLEGE ENGINEERING
ADIKAVI NANNAYA UNIVERSITY: RAJAMAHENDRAVARAM
DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING

CERTIFICATE
This is to certify that the Summer Internship work in the field of PCB DESIGN is being
submitted by GULLAPALLI LAKSHMI DHANUSHA (228867603031) in partial
fulfillment for the award of Degree of B. Tech in ECE. This work is carried out in
INTERNSHALA during the period of 01/05/2024 to 16/06/2024 to the Adikavi
Nannaya University, Rajamahendravaram during the period 2024-2025 is a record of
bonafide work carried out by under the guidance and supervision.

Internship Guide Internship Coordinator

Mrs. N. SANTOSHI Mr. B. Krishna

Assistant Professor, Assistant Professor,
Dept. of ECE, AKNUCE, RJY Dept. of ECE, AKNUCE, RJY

Course coordinator

Mr. B. SudhaKiran,
Assistant Professor,
Dept. of ECE, AKNUCE, RJY.

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iii
 DECLARATION
I GULLAPALLI LAKSHMI DHANUSHA (228867603031) hereby declare that
the summer internship work report in the field of PCB DESIGN done by me under
the guidance of Mrs.N. Santhoshi Assistant. Prof., Department of Electronics and
Communication Engineering, Adikavi Nannaya University College of Engineering,
Adikavi Nannaya University, is submitted for the partial fulfillment of requirement
for the award of the degree Bachelor of Technology in Electronics and
Communication Engineering in the academic year 2024-2025.

Gullapalli Lakshmi Dhanusha

228867603031

ACKNOWLEDGEMENT
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 I take immense pleasure to express my deep sense of gratitude to our beloved
Internship Guide Mrs.N. Santhoshi, Assistant Professor in Electronics and
Communication Engineering, Adikavi Nannaya University College of
Engineering, Adikavi Nannaya University, Rajamahendravaram for her valuable
suggestions and rare insights, for constant source of encouragement and inspiration
throughout my internship work. This internship period was a great chance of learning
and professional development.
I express my deep sense of gratitude to my beloved Course Coordinator Mr. B
Sudha Kiran, Assistant Professor in Electronics and Communication
Engineering, Adikavi Nannaya University College of Engineering, Adikavi
Nannaya University, Rajamahendravaram for the valuable guidance and
suggestions, keen interest and through encouragement extended throughout period of
Summer Internship work.
I express my deep sense of gratitude to my beloved Principal Dr. P
Venkateswara Rao, Adikavi Nannaya University College of Engineering,
Adikavi Nannaya University, Rajamahendravaram for the valuable guidance and
for permitting me to carry out this Summer Internship work at INTERNSHALA.

I grateful to my Internship coordinator Mr. B Krishna, Assistant Professor in

Electronics and Communication Engineering, Adikavi Nannaya University
College of Engineering for providing organizational support in enthusiastic
discussion, in-depth review, and providing valuable references.

I express my thanks to all the Teaching and Non-Teaching those who

contributed for their generous support and help in various ways for the successful
completion of my internship work.
Finally, I also extend thanks to my friends for their support in carrying out this work
successfully.

With gratitude,
Gullapalli Lakshmi Dhanusha
228867603031

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 ABSTRACT
This report presents here is the internship experience in pcb design, focusing on the
theoretical and practical aspects encountered throughout the program.
This internship provides hands-on exposure to the entire pcb design process, including
schematic caputure, layout design, and manufacture considerations. Tools such as
Autodesk-eagle were utilized to create efficient and reliable pub designs, emphasizing
best practices in component placement, routing and signal integrity. challengers faced
included optimizing design for manufacturability and troubleshooting in prototype
testing.
Overall, the internship enhanced technical skills and provided valuable insights into
the industry standard and practices in pcb design

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 CONTENTS
CHAPTER - 1..................................................................................................
INTRODUCTION TO HADWARE COMPONENTS & DEVELOPMENT PROCESS..............
1.1 Introduction to Electronic Components in PCB Design.......................................................
1.2 Introduction to Resistor.........................................................................................................
1.3 INTRODUCTION TO CAPACITOR:.................................................................................
1.4 Introduction to Inductor:.......................................................................................................
1.5 Introduction to PCB:.............................................................................................................

CHAPTER -2...................................................................................................
INTRODUCTION TO AUTODESK EAGLE...............................................................................
2.1 Overview of the EAGLE interface:......................................................................................
2.2 Toolbars and Menus..............................................................................................................

CHAPTER -3...................................................................................................
CIRCUIT EXPLAINATION, SCHEMATIC DESIGN & ERC ERRORS....................................
3.1 Power Supply Unit Block in PCB Design............................................................................
3.2 Microcontroller Units..........................................................................................................
3.3 Motor Driver.......................................................................................................................
3.4 Seven Segment Display......................................................................................................
3.5 Introduction -Switch, Preset & RGB LED..........................................................................

CHAPTER – 4...............................................................................................
PCB DESIGN & DRC ERRORS..................................................................................................
4.1 Schematic Capture..............................................................................................................
4.2 Component Selection and Placement..................................................................................
4.3 Routing Techniques............................................................................................................
4.4 Definition of DRC (Design Rule Check)............................................................................
4.5 Common Design Rules (Clearance, Width, Pad Size)........................................................

CHAPTER – 5...............................................................................................
BOM, MANUFACTURING DATA & COMPONENT SOLDERING.......................................
5.1 BOM generation Manufacturing Data Generators..............................................................
5.2 SMD Components Soldering..............................................................................................

CHAPTER -6.................................................................................................
HARDWARE TESTING & TROUBLESHOOTING..................................................................
6.1 Introduction to Hardware Testing Processes......................................................................
6.2 Importance of hardware testing in product development....................................................

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CONCLUSION.............................................................................................
REFERNCES................................................................................................

viii
 CHAPTER -1
INTRODUCTION TO HADWARE COMPONENTS &
DEVELOPMENT PROCESS
1.1 INTRODUCTION TO ELECTRONIC COMPONENTS IN PCB DESIGN

Printed Circuit Boards (PCBs) serve as the backbone of modern electronic

devices, providing the necessary support and interconnection for various electronic
components. Understanding the fundamental electronic components that are
integrated into PCBs is crucial for effective design and functionality.
DENFITION OF ELECTRONIC COMPONENTS:
Electronic components are the parts used in devices that construct electronic
circuits. They serve various functions, and understanding their types and roles is
essential for anyone involved in electronics. An electronic circuit is composed of
various types of components. These are active or passive.
1. Passive components:
Only dissipate or store energy Components
Resistance
Capacitance
Inductance.
2. Active components:
They take part in the transformation of the energy.
Diode
Transistor FET
SCR etc

Fig :1 Electronic components

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1.2 INTRODUCTION TO RESISTOR
A resistor is a passive two-terminal electrical component that implements
electrical resistance as a circuit element. Resistors act to reduce current flow, and, at
the same time, act to lower voltage levels within circuits.
Resistors are electronic components which have a specific value that is never-
changing, since voltage, current and resistance are related through Ohm’s law,
resistors are a good way to control voltage and current in your circuit.

Fig:2 Resistor symbol

RESISTOR COLOUR CODES
1. 1st band = 1st number
2. 2nd band = 2nd number
3. 3rd band = multiplier
4. 4th band = tolerance

Fig:3 Resistor colour code

1.3 INTRODUCTION TO CAPACITOR:

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1. Capacitor is an electronic component that stores electric charge.
The capacitor is made of 2 close conductors (usually plates) that are separated
by a dielectric material.
2. Capacitance is measured in Farads. The small capacitors usually used in
electronics are often measured in microfarads and nano-farads.
POLARITY OF CAPACITORS:
1. The shorter terminal goes on the negative side.
2. The stripe is on the negative terminal side of the capacitor. The board is
marked for positive or negative.

Fig :4a Capacitor Symbol

Fig :4b Capacitor

1.4 INTRODUCTION TO INDUCTOR:

1. An inductor, also called a coil or reactor, is a passive two-terminal electrical
component which resists changes in electric current passing through it.
2. It consists of a conductor such as a wire, usually wound into a coil.
3. Energy is stored in a form of magnetic field in the coil as long as current
flows.

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 Fig:5 Inductor Symbol

1.5 INTRODUCTION TO PCB:

A PCB is a flat board made of insulating material, such as fiberglass, with
conductive pathways that connect various electronic components. These pathways are
typically made from copper and are used to facilitate electrical connections between
components and allowing them to communicate and function together in device s like
smartphones, computers, and appliances.
The history of PCB design began in the early 20th century with the pioneering
work of Thomas Edison and later Paul Eisler, who created the first printed circuit
board in 1936 using copper foil on a bake lite substrate. The use of PCBs expanded
significantly during World War II due to the need for reliable electronic components
in military applications. This laid the foundation for the widespread adoption of PCBs
in consumer electronics, leading to innovations like solder masks in the 1950s to
enhance durability.
From the 1960s onward, advancements in photolithography and the
introduction of computer-aided design (CAD) transformed PCB manufacturing,
allowing for more complex and compact designs. The 1980s saw the rise of surface
mount technology, further miniaturizing components. As technology progressed into
the 21st century, PCBs became integral to modern devices, adapting to trends like IoT
and environmental sustainability while continuously pushing the boundaries of
integration and performance.

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TYPES OF PCB:
1 Single-Sided: Components are placed on one side, with conductive pathways on
the opposite side.

2 Double-Sided: Components and pathways can be on both sides, allowing for more
complex circuits.
3 Multilayer: Multiple layers of conductive pathways are stacked and
interconnected, allowing for compact designs and more intricate circuits.

Fig:6 Different types of PCB layers

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 CHAPTER -2
INTRODUCTION TO AUTODESK EAGLE

2.1 OVERVIEW OF THE EAGLE INTERFACE:

Autodesk EAGLE is a powerful PCB design software known for its intuitive
user interface that caters to both beginners and experienced designers. The interface is
organized into several key components, allowing users to efficiently create schematics
and PCB layouts
1.Main window
The main window is divided into several sections, including the Control Panel, Editor
Window, and Toolbars. The Control Panel provides access to project files, libraries,
and tools, while the Editor Window is where users design their schematics and
layouts.
2.Toolbars and Menus
EAGLE features customizable toolbars that provide quick access to frequently used
commands, such as selecting, moving, and routing components. The menus at the top
of the interface include options for file management, design, and configuration,
making it easy to navigate through various tasks.
3.Schematic Editor
The Schematic Editor allows users to create circuit diagrams. Components can be
added from libraries, and connections can be made using intuitive drawing tools. The
interface supports hierarchical designs, enabling users to manage complex circuits
efficiently.
4.PCB Layout Editor
In the PCB Layout Editor, users can convert their schematics into physical designs.
This editor allows for placing components on the board, routing traces, and adjusting
design rules. Features like the autorouter can assist in automating trace routing,
streamlining the design process.

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5.Design Rule Checks
EAGLE includes built-in design rule checks (DRC) that help ensure the PCB design
meets manufacturing requirements. Users can easily run checks to identify and correct
issues related to spacing, trace width, and other critical parameters.
6.3D Viewer
The integrated 3D Viewer allows designers to visualize their PCB in three
dimensions, providing insight into component placement and potential fit issues. This
feature enhances the ability to review designs before manufacturing.
7. Customization and Extensions
EAGLE supports customization through user-defined libraries and scripts, enabling
advanced users to tailor the software to their specific needs. This flexibility makes it
suitable for a wide range of projects, from simple to complex.

2.2 TOOLBARS AND MENUS

In Autodesk Eagle, the toolbar and menus are essential for navigating and utilizing the
software effectively. Here’s a brief overview of both:

2.2.1 TOOLBARS

The toolbar in Eagle provides quick access to commonly used tools and
commands. Key components include:

1. File Operations: New, Open, Save, Print, etc.

2. Editing Tools: Cut, Copy, Paste, Delete, Undo, Redo.
3. Design Tools: Options for placing components, drawing wires, adding text,
and creating polygons.
4. Navigation Tools: Zoom in/out, pan, and grid settings.
5. Layer Control: Toggle visibility for different layers in your schematic or board

layout.

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2.2.2 MENUS

The menus at the top of the window provide more comprehensive access to features:

1. File Menu: Manage files (open, save, export).

2. Edit Menu: Perform editing functions and manage components.
3. Tools Menu: Access utilities like libraries, user settings, and design rule
checks.
4. View Menu: Adjust how you view your schematic or board (zoom, grid
options).
5. Library Menu: Manage and create libraries for components.
6. Help Menu: Access documentation and support resources.

Fig:7 Toolbars and Menus in Eagle

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 CHAPTER -3
CIRCUIT EXPLAINATION, SCHEMATIC DESIGN & ERC
ERRORS

INTRODUCTION
In the field of electronic engineering, printed circuit boards (PCBs) serve as the backbone for
assembling and connecting various electronic components. The design process of a PCB is
multifaceted, requiring a comprehensive understanding of circuit theory, meticulous
schematic design, and rigorous error checking to ensure a functional final product.
This chapter enhance into three critical aspects of PCB design: the explanation of circuit
functionality, the principles of schematic design, and the identification and resolution of
Electrical Rule Check (ERC) errors.

Circuit Explanation provides insight into how individual components, such as

resistors, capacitors, and integrated circuits, interact within a circuit to achieve desired
electrical characteristics. Understanding these interactions is crucial for effective
design and troubleshooting.

Schematic Design focuses on the creation of visual representations of circuits using

standardized symbols. A well-structured schematic not only simplifies the design
process but also enhances communication and collaboration among team members,
ensuring everyone has a clear understanding of the circuit's layout and function.

ERC Errors are critical to the design validation process. These checks identify
potential issues, such as unconnected pins or incorrect connections, that could lead to
circuit failures. By addressing these errors early, designers can significantly reduce
the risk of costly revisions and enhance the reliability of the PCB.

3.1 POWER SUPPLY UNIT BLOCK IN PCB DESIGN

The Power Supply Unit (PSU) block is a fundamental section of PCB

design, ensuring that all electronic components receive the appropriate power
levels necessary for their operation. This block serves as the backbone of the entire
circuit, impacting performance, stability, and overall functionality.

System Power Budget Calculations in PCB Design

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 Power budget calculations are essential in PCB design, ensuring that the power
supplied to the system meets the demands of all components while maintaining
efficiency and reliability. This process involves estimating the total power
requirements and assessing whether the power supply can meet these needs without
exceeding its specifications.

Steps for Power Budget Calculations

Identify Components and Their Power Requirements:

1. List all components on the PCB, such as microcontrollers, sensors,

actuators, and communication devices.
2. Gather the power specifications for each component, including
operating voltage and current consumption (typically found in the
component datasheet).

Calculate Power Consumption for Each Component:

3. Use the formula: P=V×IP = V \times IP=V×I

4. Where PPP is power in watts, VVV is voltage in volts, and III is
current in amperes.
5. Multiply the voltage by the current for each component to determine
its power consumption.

Estimate Total Power Consumption:

6. Sum the power consumption of all individual components: Ptotal=∑Pi

7. This total will represent the maximum power requirement of the
system under normal operating conditions

3.2 MICROCONTROLLER UNITS

Microcontroller Units (MCUs) are integral components in modern electronic systems,
serving as the brains behind a wide array of applications, from consumer electronics
to industrial automation. These compact integrated circuits combine a processor,
memory, and input/output peripherals on a single chip, enabling them to execute tasks
efficiently and control various external devices. Understanding how MCUs function
within a circuit is essential for designing effective embedded systems. This overview

10
will explore the role of MCUs in circuit design, including schematic creation and
common challenges encountered during PCB design, such as Electrical Rule Check
(ERC) errors.
CIRCUIT EXPLANATION

A Microcontroller Unit (MCU) functions as the central control element in embedded

systems, managing various components like sensors, actuators, and communication
modules. It typically operates on a DC power source and processes input signals from
connected devices. The MCU analyse these inputs, performs computations, and
generates appropriate outputs to drive external components. A typical circuit includes
essential elements such as the power supply, the MCU itself, input devices like
sensors or buttons, output devices such as LEDs or motors, and various peripherals
for enhanced functionality. This structure allows the MCU to control and automate
tasks effectively, making it a pivotal component in modern electronics.

SCHEMATIC DESIGN

In schematic design, creating a clear and functional diagram is crucial for the
successful implementation of an MCU circuit. The first step involves selecting an
appropriate MCU that aligns with the project's requirements, considering factors like
processing power and the number of input/output (I/O) pins. Once the component is
chosen, connections must be established: the power and ground pins of the MCU need
to be connected to the power supply, and the input devices should be linked to
designated GPIO pins. Output devices are connected similarly. It is also essential to
incorporate decoupling capacitors close to the MCU to stabilize the power supply and
ensure smooth operation.

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 Fig:9 Microcontroller Unit

ERC ERRORS IN PCB DESIGN

During PCB design, Electrical Rule Check (ERC) errors can significantly affect the
functionality of the circuit. Common errors include unconnected pins, where some
pins on the MCU or other components may be left floating, leading to unpredictable
behaviour. Power supply issues can arise from incorrect or missing connections,
which may prevent the MCU from operating. Ground loops can create noise that
disrupts signal integrity, while pin conflicts might occur if multiple outputs are
connected to the same line. Additionally, ensuring that input signals are within the
MCU's specified voltage range is critical to prevent potential damage. Addressing
these issues involves visual inspections and utilizing ERC tools provided by PCB
design software to identify and rectify problems efficiently.

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3.3 MOTOR DRIVER

Motor drivers are crucial components in electronic systems that control the
operation of motors, enabling precise movement and speed control in various
applications, from robotics to automotive systems. These drivers serve as
intermediaries between a microcontroller and the motor, translating control signals
into the necessary power and direction needed to drive the motor. Understanding the
integration of motor drivers within a circuit is essential for effective PCB design. This
overview will delve into the role of motor drivers in circuit design, including
schematic creation and common challenges encountered during PCB design, such as
Electrical Rule Check (ERC) errors.

CIRCUIT EXPLANATION

In a typical circuit, the motor driver receives control signals from a microcontroller
(MCU) and adjusts the power supplied to the motor based on these signals. The motor
driver typically includes components like transistors or MOSFETs to handle the high
current required by the motor. The MCU sends PWM (Pulse Width Modulation)
signals to the motor driver to control speed and direction, while additional
connections manage power supply and feedback from the motor (e.g., encoders for
position sensing). This arrangement allows for effective control over motor behaviour,
ensuring precise operation in response to the MCU's commands.

SCHEMATIC DESIGN

Creating a schematic for a motor driver circuit involves selecting the appropriate
driver IC based on the motor type (DC, stepper, or servo) and the application
requirements. The design begins with establishing connections between the MCU and
the motor driver. This includes linking control pins from the MCU to the driver’s
input pins, where the PWM and direction signals are sent. Additionally, power
connections must be made to ensure that the motor driver receives the necessary
voltage to operate effectively. Incorporating protection elements, such as diodes for
back EMF protection, is crucial when dealing with inductive loads like motors. A
well-organized schematic not only simplifies the layout process but also serves as a
valuable reference for troubleshooting and future modifications.

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 Fig:10 Motor Driver

ERC ERRORS IN PCB DESIGN

During PCB design, common ERC (Electrical Rule Check) errors can impact the
functionality of motor driver circuits. Unconnected pins, particularly on the motor
driver or MCU, can lead to erratic behaviour or complete failure of the system. Power
supply issues, such as incorrect voltage levels or insufficient current capacity, can
prevent the motor from operating as intended. Ground loops can introduce noise,
affecting signal integrity and causing unpredictable motor behaviour. Pin conflicts
may arise if multiple outputs from the MCU are connected to the same input on the
motor driver. To address these issues, it is important to conduct thorough visual
inspections and utilize ERC tools in PCB design software to identify and resolve
potential problems before manufacturing the PCB.

3.4 SEVEN SEGMENT DISPLAY

Seven-segment displays are widely used in digital electronics to visually present
numerical information. Comprising seven LED segments arranged in a figure-eight
pattern, these displays can represent the digits 0 through 9, along with some letters
and symbols. They are commonly found in applications such as digital clocks,
calculators, and measurement devices. Understanding how to integrate seven-segment
displays into a circuit is crucial for effective PCB design. This overview will explore

14
the role of seven-segment displays in circuit design, including schematic creation and
common challenges encountered during PCB design, such as Electrical Rule Check
(ERC) errors.
CIRCUIT EXPLANATION

In a typical circuit utilizing a seven-segment display, the display consists of seven

individual LED segments and a common anode or common cathode configuration.
The microcontroller (MCU) sends control signals to the display to light up specific
segments, thereby forming the desired numeral. Each segment is controlled through a
dedicated pin from the MCU, which applies a high or low signal to illuminate the
segments accordingly. For example, to display the digit "3," the MCU would activate
the segments corresponding to the top, middle, and bottom segments, as well as the
top right and bottom right segments. Additionally, resistors are often included in the
circuit to limit current flowing through each segment, protecting the LEDs from
damage.

Fig:11 Seven Segment Display

SCHEMATIC DESIGN

When creating a schematic for a seven-segment display circuit, the first step is to
select the appropriate display type (common anode or common cathode) based on the

15
desired configuration. The display’s segments are then connected to the GPIO pins of
the MCU. Each segment (A to G) and the decimal point (DP) should be wired to
separate pins, ensuring that the MCU can control each segment independently.
Resistors should be placed in series with each segment to control the current. It’s also
common to include a switch or additional circuitry to enable multiplexing when using
multiple displays, allowing for dynamic control and reducing the number of required
MCU pins. A well-organized schematic not only facilitates easier assembly and
troubleshooting but also serves as a vital reference during PCB layout.

ERC ERRORS IN PCB DESIGN

During PCB design, common ERC (Electrical Rule Check) errors can affect the
functionality of seven-segment displays. One common issue is unconnected pins,
particularly if some segments are not correctly wired to the MCU, leading to
incomplete or incorrect numeral representation. Power supply issues, such as incorrect
voltage levels, can prevent the display from lighting up. Ground loops and improper
pin assignments can introduce noise and result in flickering or erratic display
behaviour. Additionally, ensuring that current-limiting resistors are appropriately
sized is critical to prevent excessive current that could damage the display.
Conducting thorough visual inspections and using ERC tools in PCB design software
can help identify and resolve these potential issues before manufacturing the PCB.

3.5 INTRODUCTION -SWITCH, PRESET & RGB LED

Switches, presets, and RGB LEDs are fundamental components in electronic circuits
that play vital roles in user interaction and visual feedback. Each of these elements
contributes uniquely to the functionality and aesthetics of a project.

Switches are simple electromechanical devices that allow users to control the flow of
current in a circuit. They can be momentary or toggle switches, enabling users to turn
devices on or off or select between different modes of operation. Their
straightforward design makes them essential in various applications, from consumer
electronics to industrial controls.

16
Presets, often found in the form of potentiometers or rotary switches, provide users
with a means to adjust settings such as volume, brightness, or other parameters. By
varying resistance in the circuit, presets enable fine-tuning and customization of
device behavior, enhancing user experience.

RGB LEDs (Red, Green, Blue Light Emitting Diodes) offer a dynamic way to provide
visual feedback. By mixing different intensities of red, green, and blue light, RGB
LEDs can produce a wide spectrum of colours, making them ideal for applications
that require visual alerts, indicators, or decorative lighting. Their versatility allows for
creative designs in everything from home automation systems to entertainment
devices.

Understanding how to integrate switches, presets, and RGB LEDs into a circuit is
crucial for effective PCB design. This overview will explore their roles in circuit
design, including schematic creation and common challenges encountered during
PCB design, such as Electrical Rule Check (ERC) errors.

CIRCUIT EXPLANATION

In a typical circuit involving switches, presets, and RGB LEDs, the MCU serves as
the central processing unit that interprets inputs and controls outputs.

1. Switches: When a user presses a switch, it sends a digital signal to the MCU.
The MCU can then respond by executing specific functions, such as turning
devices on or off or changing modes of operation.
2. Presets: These components are connected to the MCU’s analog input pins.
When the user adjusts the preset, it changes the voltage signal sent to the
MCU. This allows the MCU to read varying values and make adjustments
accordingly, such as changing the brightness of an LED or the volume of
audio output.
3. RGB LEDs: These are connected to the MCU’s PWM (Pulse Width
Modulation) capable output pins. By controlling the duty cycle of the signals
sent to each colour channel (red, green, blue), the MCU can mix the colours to
produce a desired hue. For example, to create a purple colour, the MCU would
activate both red and blue segments at varying intensities.

17
SCHEMATIC DESIGN

When designing a schematic for a circuit that includes switches, presets, and RGB
LEDs, several steps are essential:

1. Switches: Connect the switch to a GPIO pin on the MCU. Ensure that
appropriate pull-up or pull-down resistors are included to avoid floating pin
issues.
2. Presets: Connect the outer terminals of the potentiometer to the power supply
and ground, while the wiper (middle terminal) connects to an analog input pin
on the MCU. This setup allows the MCU to read the variable voltage as the
preset is adjusted.
3. RGB LEDs: Each colour channel (R, G, B) of the RGB LED should be
connected to a PWM-capable output pin on the MCU through current-limiting
resistors. Ensure that the common anode or common cathode configuration is
correctly accounted for in the schematic.

A clear and organized schematic will facilitate easier assembly and troubleshooting,
serving as a reference during PCB layout.

ERC Errors

During PCB design, common ERC (Electrical Rule Check) errors can arise, impacting
the functionality of circuits involving switches, presets, and RGB LEDs:

1. Unconnected Pins: Pins on switches or LEDs may be incorrectly connected or

left unconnected, leading to functionality issues. Ensure all connections are
verified against the schematic.
2. Power Supply Issues: Incorrect voltage levels or missing connections can
prevent components from operating properly. Confirm that power connections
to switches, presets, and LEDs are correctly established.
3. Pin Conflicts: Make sure that multiple outputs are not connected to the same
line without proper isolation, as this can cause short circuits or unexpected
behavior.

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4. Inappropriate Resistor Values: Ensure current-limiting resistors for RGB
LEDs are appropriately sized to prevent excessive current, which can damage
the LEDs.
5. Ground Loops: Improper grounding can introduce noise, affecting the
performance of sensitive components like analog inputs.

Utilizing ERC tools within PCB design software and conducting thorough visual
inspections can help identify and resolve these potential issues before the PCB is
manufactured.

19
 CHAPTER – 4
PCB DESIGN & DRC ERRORS

INTRODUCTION
In this chapter, we explore the process of designing a printed circuit board
(PCB) and the common types of Design Rule Check (DRC) errors encountered during
the design process.

PCB (Printed Circuit Board) design is the process of creating a physical layout
for an electronic circuit, where components are connected by conductive traces. This
process involves several stages, including schematic design, component selection, and
the actual PCB layout, which includes placing components and routing electrical
paths. One of the critical aspects of PCB design is ensuring the layout adheres to
specific rules and standards to prevent errors during manufacturing and operation.

Design Rule Check (DRC) is a vital step in the PCB design process that helps
verify if the layout meets the necessary electrical and manufacturing standards. DRC
errors include issues such as incorrect trace widths, insufficient clearances, or
improper via sizes, which can lead to malfunctioning circuits or difficulties during
PCB fabrication. Identifying and resolving these errors early in the design process
helps ensure the PCB functions properly and is manufacturable at a reasonable cost

The goal is to ensure that the PCB functions correctly while adhering to
manufacturing constraints and standards.

4.1 SCHEMATIC CAPTURE

Schematic capture is the first step in the PCB design process, where the electrical
circuit is represented visually using symbols for components, and their connections
are defined. It acts as a blueprint for the entire PCB layout. A schematic diagram is
essential because it ensures that the circuit’s functionality and electrical connections
are correct before moving on to the physical design of the PCB.

20
STEPS IN SCHEMATIC CAPTURE:

1 Component Selection:

Choose appropriate components (e.g., resistors, capacitors, transistors,

ICs) based on the circuit’s requirements. Components are typically
represented by standardized symbols in the schematic capture
software.

2 Component Placement:

Place the components on the schematic sheet. The placement should

reflect how the components will interact electrically, without
necessarily considering their final positions on the PCB. Placement in
the schematic serves as a guide for logical connections.

3 Creating Electrical Connections:

Define the connections between components using electrical wires

(often shown as lines or nets). These connections represent signal paths
or power distribution within the circuit.

4 Adding Power and Ground Nets:

Define the power supply lines (e.g., Vcc, GND) that provide electrical
power to the components. Power and ground connections are essential
for the proper operation of the circuit.

5 Labelling and Annotation:

Properly annotate all components, nets, and pins with appropriate

identifiers (e.g., R1 for the first resistor, U1 for the first IC). This
makes it easier to understand and troubleshoot the design.

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6 ELECTRICAL RULE CHECKING (ERC):

Perform an Electrical Rule Check (ERC) to verify the logical correctness of the
schematic. This check ensures that there are no unconnected pins or components,
conflicting connections, or other errors that could lead to electrical problems.

Fig:13 Schematic Capture

Tools for Schematic Capture:

There are several electronic design automation (EDA) tools available that facilitate
schematic capture:

1. Altium Designer
2. Ki CAD
3. EAGLE
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4. OrCAD
5. Proteus

These tools help designers create accurate, error-free schematics by providing features
like component libraries, automatic error detection, and real-time design validation.

Importance of Schematic Capture:

1. Foundation for PCB Layout: The schematic serves as the basis for designing
the PCB layout. Without a correct schematic, the PCB design cannot be
successful.
2. Error-Free Circuit Design: Capturing the circuit correctly ensures that the
electrical connections are accurate, preventing potential issues during the PCB
fabrication and testing stages.
3. Documentation: The schematic diagram is often used as documentation,
enabling easier debugging and modifications to the design in the future.

In summary, schematic capture is a critical phase in the PCB design process, ensuring
that the electrical circuit is correctly defined before advancing to the physical layout
and PCB fabrication.

4.2 Component Selection and Placement

Component selection and placement are essential steps in the PCB design
process that determine the functionality, performance, and manufacturability of the
circuit board.

1. Component Selection: This involves choosing components based on

electrical specifications (e.g., voltage, current), package types (SMD or
through-hole), size, availability, and cost. Components must also meet
environmental and reliability standards for the intended application.
2. Component Placement: Once components are selected, they must be
strategically placed on the PCB. Best practices include grouping components
by function, minimizing trace lengths, ensuring thermal management, and
maintaining enough spacing for routing and assembly. Proper placement

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 ensures efficient signal flow, reduces noise, and makes the PCB easier to
manufacture.

4.3 Routing Techniques

1. Manual Routing: Involves manually placing traces between components in

PCB design software. It provides full control over trace paths and allows for
optimization but can be time-consuming and error-prone for complex designs.
2. AUTOMATIC ROUTING: Utilizes algorithms to automatically route traces
between components. It’s faster than manual routing but may result in
suboptimal trace paths and layout issues like trace crossings.
3. INTERACTIVE ROUTING: A hybrid approach where the software
automatically routes some traces but allows the designer to interactively
modify the layout. This provides a balance between speed and control for
optimization.
4. DIFFERENTIAL PAIR ROUTING: Used for high-speed signals, where two
traces carry opposite signals. They are routed close together to reduce noise
and ensure signal integrity, important for applications like Ethernet or USB.
5. GROUND AND POWER PLANES: Involves dedicating layers of the PCB to
continuous ground and power distribution. This helps reduce noise, improves
signal integrity, and provides better power delivery across the board.
6. VIA ROUTING: Involves using vias to route traces between different layers
of a multi-layer PCB. It can help connect components but should be
minimized to reduce manufacturing complexity and cost.
7. CONTROLLED IMPEDANCE ROUTING: Ensures consistent impedance
(usually 50Ω for single-ended signals) across signal traces, crucial for high-
speed digital circuits and RF designs, maintaining signal integrity at high
frequencies.
8. AVOIDING TRACE CROSSINGS AND SHORT CIRCUITS: Good routing
avoids trace crossings and short circuits by using vias and maintaining
sufficient clearance between traces to ensure proper functionality and prevent
manufacturing errors.
9. POWER AND SIGNAL INTEGRITY ROUTING: Ensures power traces are
wide enough to handle current without voltage drops and that signal traces are

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 routed to avoid noise and interference, preserving the integrity of high-speed
signals.
10. DESIGN RULE CHECKS (DRC) DURING ROUTING: DRCs are used to
ensure that the routing adheres to predefined manufacturing and electrical
design constraints (e.g., minimum trace width, clearance), helping to avoid
errors and ensuring manufacturability.

Each of these routing techniques plays a vital role in ensuring that the PCB is
functional, manufacturable, and meets the performance requirements.

4.4 DEFINITION OF DRC (DESIGN RULE CHECK)

Design Rule Check (DRC) is an automated process in PCB design that ensures
the layout complies with predefined rules related to manufacturing and electrical
constraints. It checks for violations such as incorrect trace widths, insufficient
clearances, and improper via sizes.

PURPOSE:

1. ERROR DETECTION: Identifies electrical issues like unconnected nets or

shorts.
2. MANUFACTURING COMPLIANCE: Ensures the design meets fabrication
limits (e.g., minimum trace width).
3. SIGNAL INTEGRITY: Helps avoid issues that could degrade signal quality.
4. DESIGN OPTIMIZATION: Flags areas for improvement in performance and
manufacturability.

Overall, DRC helps ensure that the PCB design is error-free, manufacturable, and
performs as expected.

4.5 COMMON DESIGN RULES (CLEARANCE, WIDTH, PAD SIZE)

CLEARANCE
Refers to the minimum distance between PCB features (traces, pads, vias). Adequate
clearance prevents electrical shorts and interference. It depends on factors like
voltage, signal frequency, and the manufacturer’s capabilities.

FACTORS AFFECTING CLEARANCE:

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1. MANUFACTURING CAPABILITIES: PCB manufacturers often have
specific limits for the minimum clearance that can be achieved.
2. VOLTAGE LEVELS: Higher voltages generally require larger clearances to
prevent electrical arcing.
3. SIGNAL FREQUENCY: High-frequency circuits may require larger
clearances to minimize signal integrity issues.

TRACEWIDTH
The width of the conductive paths on the PCB. Trace width is critical to handle
current without overheating. It must also be adjusted for signal integrity in high-speed
designs and should comply with the manufacturer’s capabilities.

TOOLS FOR CALCULATING TRACE WIDTH:

1. IPC-2221 Standards: A standard for calculating trace widths based on current

requirements and copper thickness.
2. Online Trace Width Calculators: Many EDA tools and online calculators help
designers determine the appropriate trace width for specific current loads.

PAD SIZE:
The size of the metal area for component mounting. Proper pad size ensures
reliable soldering and stable component placement. It must match the component
package type and adhere to manufacturing standards for effective solder joints.

PAD SIZE STANDARDS:

• IPC-2221 Standards also define guidelines for pad sizes based on component
types (e.g., SOIC, QFP) and the desired soldering method (e.g., wave
soldering or hand soldering).
• Pad-to-Pad Clearance: Ensure that pad spacing is large enough to allow for
proper soldering and avoid short circuits.

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27
 CHAPTER – 5
BOM, MANUFACTURING DATA & COMPONENT SOLDERING

INTRODUCTION

Chapter 5 covers three crucial aspects of PCB design and production: The
Bill of Materials (BOM), Manufacturing Data, and Component Soldering. These
elements are essential to ensure the PCB is not only designed correctly but also
fabricated and assembled effectively.

• BOM (BILL OF MATERIALS): A detailed list of all components required for

the PCB, including part numbers, quantities, and specifications, ensuring that
every part is available for the manufacturing process.
• MANUFACTURING DATA: Includes all files and documentation needed by
the PCB manufacturer, such as Gerber files, drill files, and assembly drawings,
to accurately fabricate and assemble the PCB.
• COMPONENT SOLDERING: The process of attaching components to the
PCB using solder, which ensures electrical connectivity and mechanical
stability of the components.

Together, these steps ensure the efficient production and assembly of the PCB,
leading to a functional, reliable, and manufacturable final product.

5.1 BOM generation Manufacturing Data Generators

The BOM is a comprehensive list of all the components required to build the PCB. It
provides detailed information about each part, including its quantity, part number, and
specifications. The BOM serves as the foundation for component sourcing, inventory
management, and assembly.

STEPS TO GENERATE A BOM:

1. COMPONENT SELECTION: After designing the schematic, each component

used in the design must be identified with its part number, manufacturer, and
description.

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2. SPECIFICATION DETAILS: Include electrical characteristics (e.g.,
resistance, capacitance, power ratings) and physical attributes (e.g., package
type, size).
3. QUANTITY: The number of units required for each component is specified,
which helps in procurement and inventory planning.
4. FOOTPRINTS AND PLACEMENT: Ensure the BOM includes details on
component footprints and placements to help with the assembly process.
5. MANUFACTURER & SUPPLIER INFORMATION: Include manufacturer
details, alternate parts, and part numbers for sourcing and purchasing.

TOOLS FOR BOM GENERATION:

1. PCB DESIGN SOFTWARE (e.g., Altium Designer, Eagle, Ki CAD): These

tools automatically generate the BOM by extracting component data from the
schematic and layout files.
2. SPREADSHEET EXPORT: Many tools allow for BOM data to be exported
into spreadsheets, which are easily customizable for various suppliers.

PURPOSE OF THE BOM:

1. Ensures all components are accounted for during sourcing and assembly.
2. Helps manage inventory and avoid component shortages.
3. Assists in maintaining consistency across different production batch

Fig: Bill of Materials (BOM)

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MANUFACTURING DATA consists of files needed for PCB fabrication and
assembly, ensuring the design is accurately produced and assembled.

KEY MANUFACTURING DATA TYPES:

1. GERBER FILES: Represent the PCB layers (copper, solder mask, etc.).
2. NC DRILL FILES: Define drill hole locations and sizes.
3. PICK-AND-PLACE FILES: Provide component placement coordinates for
assembly.
4. Stencil Files: Define solder paste application.
5. ASSEMBLY DRAWINGS: Visual guides for component placement.

Both BOM and manufacturing data are essential for seamless PCB production and
assembly.

5.2 SMD COMPONENTS SOLDERING

SMD (SURFACE-MOUNT DEVICE) SOLDERING is a process used to attach

components directly to the surface of a PCB without the need for through-holes. This
method is widely used in modern PCB assembly due to its ability to handle smaller,
more compact components and increase the density of circuits.

SMD SOLDERING PROCESS:

1. SOLDER PASTE APPLICATION: A layer of solder paste is applied to the

PCB pads using a stencil. This paste consists of tiny solder balls suspended in
flux, which will melt during the soldering process to form strong electrical and
mechanical connections.
2. COMPONENT PLACEMENT: SMD components are placed on the solder
paste-covered pads using automated pick-and-place machines. The
components are accurately positioned on the board to align with the pads for
soldering.
3. REFLOW SOLDERING: The PCB is passed through a reflow oven, where it
is heated to a temperature that causes the solder paste to melt and form solid
solder joints between the component leads and the PCB pads. The process
ensures that the solder flows evenly around the leads, creating a reliable bond.

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4. INSPECTION AND TESTING: After reflow soldering, the board is visually
inspected, often using automated optical inspection (AOI) systems, to check
for misaligned components, solder bridges, or insufficient solder joints.
Additional testing, such as X-ray inspection, may be used for hidden solder
joints in complex components (e.g., BGA packages).
5. FINAL CLEANING AND QUALITY CHECK: After inspection, the PCB
may be cleaned to remove any flux residues. The board undergoes a final
quality check to ensure that all components are securely soldered, and the
circuit functions as expected.

Fig Soldering Process

ADVANTAGES OF SMD SOLDERING:

1. HIGHER COMPONENT DENSITY: SMD components are smaller and allow

for more compact designs, enabling high-density circuits.
2. FASTER PRODUCTION: The automated pick-and-place and reflow
soldering processes significantly speed up assembly, making it more suitable
for mass production.
3. IMPROVED PERFORMANCE: SMDs typically have shorter lead lengths,
which help reduce inductance and resistance, improving the performance of
high-frequency circuits.

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 CHAPTER -6
HARDWARE TESTING & TROUBLESHOOTING

6.1 INTRODUCTION TO HARDWARE TESTING PROCESSES

Hardware testing is a critical phase in the development and production of

electronic devices, ensuring that the physical components of a system function
correctly and reliably. In the context of Printed Circuit Boards (PCBs), hardware
testing is used to identify faults, verify functionality, and validate design integrity
before mass production or deployment.

The hardware testing process typically starts with design validation, where
simulations are used to predict how the circuit will behave under different conditions.
Once a prototype is created, physical testing begins with steps like visual inspections,
functional testing, and electrical tests to ensure the board operates as intended. More
advanced tests such as in-circuit testing (ICT), boundary scan, and thermal testing are
employed to detect issues that might not be visible to the eye, such as short circuits,
signal integrity problems, or overheating components.

The overall goal of hardware testing is to ensure that the design meets its
specifications, operates reliably over time, and performs well under real-world
conditions. It also helps in troubleshooting and improving designs, ensuring that the
final product is safe, durable, and efficient.

6.2 IMPORTANCE OF HARDWARE TESTING IN PRODUCT

DEVELOPMENT
Hardware testing in PCB design is crucial for ensuring that the final product
functions as intended, is reliable, and meets all necessary specifications. During
the development of a printed circuit board (PCB), testing allows engineers to
detect issues early, optimize design performance, and guarantee that the hardware
will perform under real-world conditions. Below are the key reasons why
hardware testing is vital in PCB design:

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4. VERIFICATION OF DESIGN ACCURACY: Testing confirms that the PCB
operates as intended, meeting the specified design requirements for voltage,
signal integrity, and functionality.
5. EARLY DETECTION OF ISSUES: Testing helps identify design and
manufacturing flaws early, saving costs and time by addressing issues before
mass production.
6. ELECTRICAL AND SIGNAL INTEGRITY: It ensures that the PCB
performs correctly without issues like noise, signal degradation, or power
supply fluctuations.
7. THERMAL AND ENVIRONMENTAL PERFORMANCE: Hardware testing
checks for overheating, proper heat dissipation, and resilience to
environmental factors like temperature and humidity.
8. RELIABILITY AND DURABILITY: Ensures that the PCB can withstand
long-term use under varying conditions, reducing the risk of early failures.
9. QUALITY ASSURANCE: Testing ensures that the final product meets safety
standards and performs consistently, improving overall product quality.
10. COST REDUCTION AND RISK MITIGATION: Early detection of problems
reduces the risk of expensive redesigns, recalls, or field failures, ultimately
lowering overall costs.
1. FASTER TIME-TO-MARKET: Testing ensures that the product is
production-ready, reducing delays and accelerating the development cycle.

HARDWARE TESTING & TROUBLESHOOTING TECHNIQUES IN PCB

DESIGN:

In PCB design, hardware testing and troubleshooting are critical steps to ensure that
the final product is functional, reliable, and free from defects. There are several
techniques and methods used to test and troubleshoot PCBs effectively. Below are
some key techniques

1. VISUAL INSPECTION

• PURPOSE: The most basic form of testing, visual inspection allows engineers
to check for obvious issues like misaligned components, broken traces,
soldering defects, or missing parts.

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 • TOOLS: Magnifying glass, microscope, or Automated Optical Inspection
(AOI) systems.
• COMMON ISSUES: Solder bridges, cold solder joints, component
misplacement, and damaged traces.

2. CONTINUITY TESTING

• PURPOSE: Continuity testing checks for open circuits or broken traces in the PCB. It
ensures that electrical connections are intact.
• TOOLS: Digital Multimeter (DMM) or Automated Test Equipment (ATE).
• COMMON ISSUES: Broken traces, disconnected vias, or unintentional shorts.

Fig: Continuity Test

3. IN-CIRCUIT TESTING (ICT)

1. PURPOSE: ICT is used to test individual components on the PCB to verify

their functionality and correct placement. It checks for component shorts, open
connections, and proper soldering.
2. TOOLS: In-Circuit Testers (ICT), probes, and specialized software.
3. COMMON ISSUES: Faulty components, incorrect pin connections, and
component misplacement.

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 Fig: ICT Testing

4. FUNCTIONAL TESTING

1. PURPOSE: Functional testing ensures that the PCB performs the desired tasks
and operates under real-world conditions. This could involve checking output
voltages, signal waveforms, or system behavior.
2. TOOLS: Oscilloscopes, signal generators, power supplies, and digital
multimeters.
3. COMMON ISSUES: Incorrect output voltages, failure to execute specific
functions, and signal distortion.

5.THERMAL IMAGING AND TEMPERATURE TESTING

1. PURPOSE: Thermal testing helps identify hot spots on the PCB that may
indicate over-heating components or poor thermal management.
2. TOOLS: Thermal cameras, thermocouples, or infrared sensors.
3. COMMON ISSUES: Overheating components, inadequate heat dissipation, or
poor thermal design.

6. OSCILLOSCOPE TESTING

1. PURPOSE: Oscilloscopes are used to monitor and analyze waveforms of

signals on the PCB to ensure that they meet the required timing and voltage
levels.
2. TOOLS: Digital Oscilloscope.
3. COMMON ISSUES: Incorrect signal timing, voltage spikes, or noise.

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7. POWER INTEGRITY TESTING

1. PURPOSE: Power integrity testing ensures stable voltage and current delivery
to all components on the PCB without fluctuations or noise.
2. TOOLS: Power supplies, digital oscilloscopes, and current probes.
3. COMMON ISSUES: Voltage drops, noise, ripple in the power supply, and
inadequate decoupling.

8.DEBUGGING WITH LOGIC ANALYZERS

1. PURPOSE: Logic analyzers help capture and analyze the digital signals from
microcontrollers, processors, or other digital components to identify timing
issues or logic errors.
2. Tools: Logic analyzer, probes.
3. COMMON ISSUES: Timing issues, incorrect logic levels, or missing signals.

9.EMI/EMC TESTING

1. PURPOSE: Electromagnetic Interference (EMI) and Electromagnetic

Compatibility (EMC) testing ensures that the PCB does not interfere with
other devices and complies with electromagnetic standards.
2. TOOLS: EMI testing chambers, spectrum analyzers.
3. COMMON ISSUES: Excessive radiation, improper grounding, or shielding.

10. ENVIRONMENTAL TESTING

• PURPOSE: Environmental testing subjects the PCB to extreme conditions

such as high and low temperatures, humidity, vibration, or shock to ensure
robustness in various operating environments.
• TOOLS: Temperature chambers, vibration simulators, and humidity
chambers.
• COMMON ISSUES: Component failure due to temperature extremes,
humidity-induced corrosion, or physical damage under shock/vibration.

36
 CONCLUSION
The conclusion of PCB design is that it is a complex and challenging process that
requires a thorough understanding of design principles and best practices. The
importance of attention to detail in PCB design, including considerations for signal
integrity, component placement, power distribution, and minimizing electromagnetic
interference.
This internship has provided me with a comprehensive understanding of PCB design
principles, methodologies, and industry-standard software tools. Throughout the
internship, I gained hands-on experience in designing, simulating, and optimizing
PCBs for various applications.

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 REFERNCES
https://resources.pcb.cadence.com/blog/2024-reference-designator
https://resources.altium.com/p/best-practices-using-reference-designs
https://www.reddit.com/r/PrintedCircuitBoard/comments/117aezr/
advanced_pcb_design/

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