Welcome to the world of electronics fault finding! If you’re just starting out, troubleshooting electronic devices can seem like a daunting task. Yet, with the right approach and tools, you can swiftly move from a beginner to a knowledgeable enthusiast or even a professional.
In this article, we will cover some basic yet most common techniques for fault finding in electronics. If you want to dive deeper into the topic then take a look at our 5-day Introduction to Electronics Fault Finding course.
You can also see details on all of our Electronics Skills Courses in this article.
Electronics Fault Finding Techniques for Beginners
Starting with Component Identification
When you’re new to electronics fault finding, the first step is recognising and understanding the various components on a circuit board. Each component, whether it’s a resistor, capacitor, transistor, or integrated circuit, plays a specific role in the functionality of the device.
Begin by familiarising yourself with the physical appearance and typical symbols used to represent these components in circuit diagrams. This knowledge will be invaluable when you need to locate components on an actual circuit board or follow a schematic during troubleshooting. This is something we cover in depth during the first 2 days of our Introduction to Electronics Fault Finding course.
There are some basic tools, such as a digital microscope that will aid you in the identification of different components. These tools will also help you inspect components closely for any signs of damage like cracking, burning, or corrosion, which are often the culprits behind electronic malfunctions. Identifying which components look out of place or damaged is a critical skill in electronics fault finding.
Finally, understanding how these components interact within the circuit is crucial. You don’t need to become an overnight expert, but having a grasp of basic electronic principles, such as how current flows through a circuit or how capacitors and resistors control that flow, will greatly aid in your fault finding missions. This foundational knowledge allows you to make informed guesses about where faults might occur based on symptoms.
Electronics Fault Finding Using a Multimeter
A multimeter is an essential tool in any electronics kit. It can measure voltage, current, resistance, and sometimes even more complex values like capacitance and frequency. Learning to use a multimeter effectively is a big step towards successful electronics fault finding.
Start by learning to measure voltage, both AC and DC. This is crucial for testing batteries, power supplies, and points in a circuit to ensure the right voltages are present. Incorrect voltages can be a clear indicator of a problem. For instance, if a device isn’t turning on, checking the power supply with your multimeter will tell you whether the issue is with the power or elsewhere.
Measuring resistance is next. This function helps you check the integrity of connections and the condition of various components. A broken circuit will show infinite resistance, while a short circuit shows much lower than expected resistance.
Lastly, become proficient in using your multimeter’s continuity function. This setting beeps when there is a direct connection between two points, which is invaluable for checking if circuits are properly connected or if there are unintended shorts.
Learning to use a Digital Multimeter is something we introduce on day 2 of our Introduction to Electronics Fault Finding course. You will also have plenty of opportunity for practice using one throughout the course.
Electronics Fault Finding Using Oscilloscopes
Oscilloscopes might seem intimidating at first glance, but they are incredibly powerful tools for diagnosing problems in electronic circuits. They allow you to see the actual electrical signals as they pass through the circuit, providing a visual snapshot of what’s happening in real-time, measuring both amplitude and frequency.
Begin by understanding what an oscilloscope can do for you. It shows how signals change over time, which can help you pinpoint issues like signal interference, unexpected voltage drops, or erratic signal behaviours that are difficult to detect with other tools.
For practical use, start with simple measurements. Hook up the oscilloscope to a part of your circuit where you expect a stable signal and observe what the waveform looks like. A stable DC power supply, for instance, should show a flat line at a specific voltage level. If the line fluctuates, there’s likely an issue with the power supply.
There is much more you can use an Oscilloscope for, and we cover this during our Introduction to Electronics Fault Finding course, where you will get the chance to work with our new state-of-the-art machines.
Electronics Fault Finding and Testing Power Supplies
Testing power supplies is a fundamental skill in electronics fault finding. Since they provide the necessary power for the entire circuit, any fault here can render the whole system inoperative.
First, check the output voltage with a multimeter. Compare the reading to what is expected based on the specifications of the power supply. Significant deviations could indicate issues like a failing component or an overloaded supply.
Next, check for stability. Power supplies should deliver a stable voltage regardless of variations in load or environmental conditions. If you observe fluctuating voltage levels, especially under load, this might suggest components within the supply are degrading or are improperly configured.
Heat can also be an indicator of trouble. If parts of your power supply are excessively hot, this could be a sign of inefficiency or failure. Using a thermal camera, thermal sensor, or even just your hand (carefully, power off) can help identify hot spots that warrant closer inspection.
Circuit Testing in Electronics Fault Finding
Circuit testing involves methodically checking each segment of a circuit to ensure it is working as expected. This process helps isolate where faults might be occurring.
Start with a visual inspection. Look for any obvious signs of damage such as burnt components, cracked boards, or loose connections. These can often lead to malfunctions and are usually the first culprits to investigate.
Next, use your multimeter to test continuity between different points in the circuit. This helps ensure that each connection is solid and that there are no breaks in the circuit where there shouldn’t be.
Then, power up the circuit and use your multimeter or oscilloscope to check the voltage levels at various points. This helps verify that each part of the circuit is receiving the power it needs to operate correctly. Discrepancies here can help you zero in on areas that need further investigation.
Fault Finding with Number Systems/ Logic Gates
In digital electronics, understanding number systems and logic gates is crucial for fault finding. These components are the building blocks of digital circuits, and errors within them can lead to the entire system behaving unpredictably. This is something we cover in detail on the third day of our Introduction to Electronics Fault Finding course.
Begin by familiarising yourself with binary and hexadecimal number systems as these are commonly used in digital electronics. Knowing how to convert between these and the decimal system can help you interpret what’s happening in a circuit.
Logic gates like AND, OR, NOT, NAND, NOR, XOR, and XNOR perform basic logical functions and are used to control digital circuits. Using a logic probe or oscilloscope can help you visualise how signals are passing through these gates, which is invaluable for diagnosing issues.
Check for common faults in digital circuits like floating inputs, which can cause unpredictable behaviour, or shorted outputs, which can prevent a circuit from functioning entirely. Testing each gate individually and comparing the actual outputs with expected outputs based on your inputs can reveal where the problems lie.
Learn Electronics Fault Finding with The Electronics Group
Starting your journey in electronics fault finding can initially seem challenging, yet it becomes highly rewarding as you improve your skills and confidence. By understanding and utilising the techniques discussed—like using multimeters, oscilloscopes, and other specific test equipment – you’ll find yourself better equipped to tackle most common electronic faults.
Always approach electronics fault finding with a methodical mindset and remember that patience and practice are your best tools. For a more thorough Introduction to Electronics Fault Finding, take a look at our 5 day course or get in touch with us for more information.
