Printed Circuit Boards and Using a Multimeter

Q: What is a Printed Circuit Board (PCB) and what base components does it consist of?

A Printed Circuit Board (PCB) is a rigid, permanent board that mechanically supports and connects components using conductive copper tracks etched onto an insulating substrate .

Q: What are the two common substrate materials used for PCBs?

The two main substrate materials are FR-4 (glass-reinforced epoxy resin) and SRBP (synthetic resin bonded paper).

Q: What are the main advantages of using a PCB over a breadboard?

PCBs provide permanent and robust connections, a compact size , greater reliability , and allow rapid mass production .

Q: What is the difference between a schematic diagram and a PCB layout?

A schematic diagram shows logical connections using standard circuit symbols, whereas a PCB layout shows physical copper tracks, component placements, and solder pads.

Q: What are the five steps in the school-level PCB manufacturing process?

The five steps are: CAD Design , Masking (Resist Application) , Etching (in Ferric Chloride) , Drilling , and Populating and Soldering .

Q: What design errors must be avoided when laying out PCB tracks and pads?

Avoid placing tracks too close together (which risks solder bridges/short circuits) and making pads too small (which makes drilling hard and weakens solder joints).

Q: What three primary electrical properties does a standard multimeter measure?

A multimeter measures Voltage (in Volts, \(V\)), Current (in Amperes, \(A\)), and Resistance (in Ohms, \(\Omega\)).

Q: How should a multimeter be connected to measure voltage, current, and resistance?

Measure voltage in parallel (power ON), current in series by breaking the circuit (power ON), and resistance across the component with power OFF .

Q: What does a continuity test do and how is it used in circuit testing?

A continuity test checks if an electrical path is complete, emitting an audible beep when it detects a continuous, low-resistance path.

Technology and Design 8900 · CCEA GCSE · 6 min read · Updated: 1 Sept 2026

Unit 2 Option A: Printed Circuit Boards & Using a Multimeter

Welcome to your study guide for Printed Circuit Boards (PCBs) and Using a Multimeter! Whether you are building circuits in the workshop or preparing for your CCEA GCSE examination, mastering these practical electronic skills is essential. Don't worry if circuit design and electrical testing seem tricky at first—we will break down every single step clearly.

Part 1: Printed Circuit Boards (PCBs)

What is a Printed Circuit Board?

In electronic prototyping, you often start by plugging components into a temporary breadboard. However, temporary setups can come loose easily. A Printed Circuit Board (PCB) is a permanent, rigid board that mechanically supports and electrically connects electronic components.

Instead of messy tangled wires, a PCB uses thin conductive pathways called tracks (or traces) etched from copper sheets bonded onto a rigid, non-conductive base material (the substrate).

Substrate Materials

The base board itself must be an electrical insulator so that electricity only flows where we want it to (through the copper tracks). In school workshops and industry, two main substrate materials are used:

• FR-4 (Glass-reinforced epoxy resin): A high-quality, strong, and flame-resistant composite material widely used in commercial and school electronics.
• SRBP (Synthetic Resin Bonded Paper): A traditional, lower-cost laminate base made of paper layers soaked in resin.

Why Use a PCB Instead of a Breadboard?

• Permanent and Robust: Components are soldered in place, meaning connections cannot fall out when moved.
• Compact Size: Neatly laid out copper tracks take up far less space than jumper wires.
• Reliability: Eliminates loose wiring faults.
• Mass Production: Identical boards can be produced quickly and accurately in large quantities.

From Schematic to PCB Layout

Before making a physical board, you must turn a schematic diagram (a circuit drawing using standard symbols) into a PCB layout:

• Schematic Diagram: Shows how components connect logically using standard electrical symbols.
• PCB Layout: Shows the physical placement of components, copper tracks (lines of copper), and pads (round or oval copper rings with holes where component leads are inserted and soldered).

The School-Level PCB Manufacturing Process

Making a PCB in a school workshop follows a precise five-step sequence:

Step 1: CAD Design
The circuit is designed on computer software (such as Circuit Wizard or Yenka). The software converts the circuit diagram into a track-and-pad layout.

Step 2: Masking (Resist Application)
A protective layer called a resist or photo-mask is applied to the copper-clad board. This mask covers only the tracks and pads, shielding them from chemicals in the next step.

Step 3: Etching
The board is placed into a chemical acid bath, typically Ferric Chloride. The chemical dissolves all the exposed, unprotected copper. The copper protected underneath the mask remains completely intact.

Step 4: Drilling
Small holes are drilled through the centre of each copper pad using a mini drill press, creating through-holes for the component legs.

Step 5: Populating and Soldering
Components are inserted through the holes from the top (component side) and permanently joined to the copper pads underneath using solder.

PCB Design Pitfalls to Avoid in the Exam

• Tracks too close together: If tracks are drawn too close, solder can bridge across them during assembly, causing an unwanted short circuit.
• Pads too small: Small pads make drilling difficult and do not provide enough surface area for a solid solder joint.

Quick Review — PCBs: PCBs replace messy wiring with permanent copper tracks on an insulating base (like FR-4 or SRBP). The process flows: Design \(\rightarrow\) Mask \(\rightarrow\) Etch (Ferric Chloride) \(\rightarrow\) Drill \(\rightarrow\) Populate/Solder.

Part 2: Using a Multimeter

What is a Multimeter?

A multimeter is a versatile handheld test instrument used to test, measure, and troubleshoot electronic circuits. It combines several testing functions into one single meter:

1. Voltage (\(V\)) — measured in Volts (\(\text{V}\) or \(\text{mV}\))
2. Current (\(I\)) — measured in Amperes (\(\text{A}\) or \(\text{mA}\))
3. Resistance (\(R\)) — measured in Ohms (\(\Omega\) or \(\text{k}\Omega\))

How to Measure Voltage, Current, and Resistance

1. Measuring Voltage (Voltmeter Mode)
• How to connect: Always connect the multimeter in parallel across the component you are testing.
• Circuit status: The circuit must be switched ON and powered.
• Setting: Select the correct type of voltage—DC (Direct Current) for battery circuits, or AC (Alternating Current) if testing mains-derived AC signals.

2. Measuring Current (Ammeter Mode)
• How to connect: Always connect the multimeter in series with the circuit.
• How to do it: You must physically break open the circuit path and insert the multimeter leads so that current flows through the meter.
• High Current Port: For measuring larger currents (e.g., up to \(10\text{ A}\)), the red lead must be moved to the dedicated high-current socket to protect the meter's internal fuse.

3. Measuring Resistance (Ohmmeter Mode)
• Golden Rule: The circuit power must be completely disconnected (switched OFF)!
• Why? An ohmmeter works by sending its own tiny internal test current through the component. If the circuit is powered, external voltage will distort the reading and can damage the meter.
• How to connect: Place the probes across the component being measured.

Continuity Testing

The continuity test mode is one of the most useful diagnostic settings on a multimeter:

• It tests whether an electrical path is complete (continuous).
• The meter emits an audible beep if there is a complete, low-resistance path (typically less than \(\approx 30\text{–}50\,\Omega\)).
• Workshop Uses: Checking for broken copper tracks on a PCB, finding faulty switches, or detecting accidental solder bridges (short circuits) between adjacent tracks.

Applying Ohm's Law with Multimeter Readings

When analyzing test results, you will use Ohm's Law:

\(V = I \times R\)

Where:
• \(V\) = Voltage in Volts (\(\text{V}\))
• \(I\) = Current in Amperes (\(\text{A}\))
• \(R\) = Resistance in Ohms (\(\Omega\))

Memory Triangle Tip: Place \(V\) at the top of the triangle, with \(I\) and \(R\) at the bottom. Cover the letter you want to calculate:
• To find Voltage: \(V = I \times R\)
• To find Current: \(I = \frac{V}{R}\)
• To find Resistance: \(R = \frac{V}{I}\)

Common Multimeter Pitfalls in Examinations

• Connecting Current in Parallel: Connecting an ammeter across a component in parallel creates a dead short and will blow the multimeter's internal fuse.
• Measuring Resistance with Power ON: Always turn off the power supply before checking resistance or continuity.
• Scale and Unit Confusion: Pay close attention to scale prefixes on manual-ranging meters:
— \(1\text{ k}\Omega = 1\,000\,\Omega\)
— \(1\text{ V} = 1\,000\text{ mV}\)
— \(1\text{ A} = 1\,000\text{ mA}\)

Quick Review — Multimeter Connections:
• Voltage: Connected in parallel (Power ON)
• Current: Connected in series (Break circuit, Power ON)
• Resistance / Continuity: Connected across component (Power OFF)

Quick check

Can you answer these now?

Open each question to check the key ideas from this chapter.

What is a Printed Circuit Board (PCB) and what base components does it consist of?

A Printed Circuit Board (PCB) is a rigid, permanent board that mechanically supports and connects components using conductive copper tracks etched onto an insulating substrate.

What are the two common substrate materials used for PCBs?

The two main substrate materials are FR-4 (glass-reinforced epoxy resin) and SRBP (synthetic resin bonded paper).

What are the main advantages of using a PCB over a breadboard?

PCBs provide permanent and robust connections, a compact size, greater reliability, and allow rapid mass production.

What is the difference between a schematic diagram and a PCB layout?

A schematic diagram shows logical connections using standard circuit symbols, whereas a PCB layout shows physical copper tracks, component placements, and solder pads.

What are the five steps in the school-level PCB manufacturing process?

The five steps are: CAD Design, Masking (Resist Application), Etching (in Ferric Chloride), Drilling, and Populating and Soldering.

What design errors must be avoided when laying out PCB tracks and pads?

Avoid placing tracks too close together (which risks solder bridges/short circuits) and making pads too small (which makes drilling hard and weakens solder joints).

What three primary electrical properties does a standard multimeter measure?

A multimeter measures Voltage (in Volts, \(V\)), Current (in Amperes, \(A\)), and Resistance (in Ohms, \(\Omega\)).

How should a multimeter be connected to measure voltage, current, and resistance?

Measure voltage in parallel (power ON), current in series by breaking the circuit (power ON), and resistance across the component with power OFF.

What does a continuity test do and how is it used in circuit testing?

A continuity test checks if an electrical path is complete, emitting an audible beep when it detects a continuous, low-resistance path.

What is Ohm's Law and how can its formula be rearranged?

Ohm's Law states \(V = I \times R\), which rearranges to \(I = \frac{V}{R}\) and \(R = \frac{V}{I}\).

What common mistakes must be avoided when operating a multimeter?

Avoid connecting an ammeter in parallel, measuring resistance with power turned ON, and misinterpreting scale prefixes (\(\text{m}\) vs \(\text{k}\)).

Ready to test yourself?

Turn these notes into exam-style practice. Get unlimited AI questions on this topic with instant marking and explanations.

Practise This Topic

More Technology and Design 8900 chapters

* The content provided by thinka is generated by AI and may not always be accurate or up-to-date. Please use it as a supplementary resource and verify with official materials.

Put These Notes into Practice

Reading the notes is a great start. Now practise with unlimited AI-generated questions and get instant feedback. 100,000+ students are already improving their grades.

Start Practising Now View Pricing

Done reading? Test yourself with AI practice questions

Practise This Topic Now