TESTING ELECTRONIC COMPONENTS 

In this modern world, different devices have been developed and enhanced for the advancement and meet the user satisfaction. Many gadgets and appliances are digitalized their performance, for example from Film Camera that is limited photos and developed the captured photos into dark room using the manual process to up to Digital Camera that automatically produce output using softcopy or hardcopy and with unlimited taking of pictures depending how bigger your memory card can store. 

In your generation today, how will you define technology as part of your lives and what are those changing scenario that technology had cover from manual operation to automatic operation? Can you give your observation base on your experience you encountered? 

Computer Electronic Components 

An electronic circuit is a structure that directs and controls electric current to perform various functions including signal amplification, computation, and data transfer. It comprises several different components such as resistors, transistors, capacitors, inductors, and diodes.

Different Methods in Testing an Electronic Component 

A. Automated is a method using tools that are capable of executing tests, reporting outcomes and comparing results with earlier test runs. Tests carried out with these tools can be run repeatedly, at any time of the day. The method or process being used to implement automation is called a test automation framework.

B. Debugging is part of the software testing process and an integral part of the entire software development lifecycle. The debugging process starts a soon as code is written and continues in successive stages and combined with other units of programming to form a software product.

C. Inspection is an organized examination or formal evaluation exercise. In engineering activities, inspection involves the measurements, tests, and gauges applied to certain characteristics in regard to an object or activity. It is a test headed by a person using procedures, processes and measurements to meet certain standards or requirements.

D. Platform testing also called an Open Test Standard (OTS) which is a set of specifications defining test methods for diverse components of computer and electronic systems to be marketed as complete products. It requires a platform or a medium.

E. Prototyping is a manner of releasing a new model or design unit. It allows the designer and client to assess the viability of a design.

Testing Strategy 

• Passive testing is a process of testing the electronic components that do not have the ability to control electric current by means of another electrical signal. Examples: Capacitors, resistors, inductors, transformers, and some diodes Electronic components, both active and passive, are lifeline of any printed circuit board assembly. They both play vital roles in the functioning of any electronic device. 

• Dynamic testing is an electronic test that place a wide range of performance demands on static and dynamic test equipment. The equipment is used to validate new designs, improve manufacturing processes and prove the quality of end products. Mechanical testing requirements involve static, dynamic and fatigue testing in tensile, compression, shear test modes.

- Testing the mechanical endurance and integrity of electronics components and assemblies is important to validate designs, improve manufacturing and ensure the reliability of final products.

• In- Circuit Testing is a test of equipment that provides a useful and efficient form of printed circuit board test by measuring each component one at a time to check that it is place and of the correct value. As most faults on a board arise out of the manufacturing process and usually consist of short circuits, open circuits or wrong components, this form of testing catches most of the problem on a board. These can easily be checked using simple measurements or resistance, capacitance, and sometimes inductance between two points on the circuit board.

Elements of In-Circuits Test Equipment 

a. In circuit tester - The in-circuit test system consists of a matrix of drivers and sensors that are used to set up and perform the measurements. There may be 1000 or more of these driver sensors points. These are normally taken to a large connector conveniently located on the system.

b. Fixture – This is the variety of boards designed specifically for a particular board and acts as an interface between the board and the in-circuit tester. The in-circuit test system connector interfaces with the second part of the tester which is the fixture. It takes the connections for the driver sensor points and routes them directly to the relevant points on the board using a “bed of nails”.

c. Software - It is written for each board type that can be tested. It instructs the test system what tests to perform between what points and details of the pass/fail criteria.

Proper Procedures and Basic Guidelines in Testing Electronic Components of the Computer 

Testing and checking electronic components of a computer is a risky procedure to the person/learners without prior knowledge. Electronic components consist of hazardous materials and elements such as electricity, mercury or any harmful chemical part of every electronic device. Before you undergo in testing and checking, proper procedure must follow and observed.

1. Planning 

Planning is the procedure that must be followed accordingly to the cycle of computer machines, specifically in terms of troubleshooting. Troubleshooting is a step-by-step procedure conducted by technical experts with proper skills and knowledge.

Before you perform testing and checking, the peripherals of the computer especially electronic components, proper planning is highly required to do before the actions are applied. Remember that the electronic components are hazardous parts of the computer. 

In performing the required testing process, there are lots of considerations you need to give an action, always ready the list of your condition and action in order to perform the proper procedure, you must do this follow planning guide: 

a. Housekeeping helps control or eliminate workplace hazards. Poor housekeeping practices frequently contribute to incidents. If the sight of paper, debris, clutter and spills is accepted as normal, then other more serious hazards may be taken for granted. 

b. Emergency Kit is highly required to prepare for any unexpected happening while testing and checking. Some of the electronic components of computer are in metallic frame or elements that have a sharp edge of lines, or voltage problems that can cause fire or short-circuit problems. 

c. Emergency Exit Plan is one of the requirements for planning to ensure that every technical working area is safe for everybody working around if in case of emergency that need to leave the area as soon as possible considering that computer systems are composed of different electrical and electronic device that accepts electricity. 

d. Prepare appropriate troubleshooting tools/equipment are the most important for troubleshooting, their specific functions are highly needed to fix and supplement to do the work. Before you begin the task, make sure that all of your tools are functional and in good condition to ensure safety. Remember some tools are dangerous to use if not in good condition or damage. It can cause trouble to the user or to the machine itself.

e. Safety Measures Whenever you are working on any electronic equipment, your own safety has come to first. Every electronic component of computers can give you danger or risky element in every time you’re working with. Electricity must be handled properly or else it can injure or cause fatalities to a person. The following are some safety measures to observe:  

• Always turn off the equipment and unplug it before you begin to work.  

• If you have to run testing while the equipment is operating, turn the equipment on and make sure you test carefully, and then turn off the equipment again.  

• Wear rubber gloves and shoes before you begin to test.  

• Try to do the work with one hand, while keeping the other in your pocket. That keeps the possible current paths away from your heart.  

• Don’t attempt test or checking when you are tired or in a rush.  

• Always assume that all electronic parts of the computer have always electrical charge even if you turn off the main power source.

2. Preparing 

In Computer Systems Servicing, preparing some tools and equipment is a good practice in any cost. It is important in giving a satisfaction to a technical person to do a work when all of his/her needs like (equipment/tools/materials) are ready to be used. Conditioning the tools and equipment in preparation for technical troubleshooting will help solve the problems and maintain the consistency of the computer.

Tools Needed to Prepare Before Checking Electronic Components

• An antistatic wrist strap or antistatic strap wraps around your wrist like a bracelet, with a conductive cord attached to the computer. This strap keeps the user grounded, which helps prevent electrostatic damage (ESD) to a computer or any other electrostatic sensitive device. 

• Screw drivers have only two purposes: to insert/drive screws and to remove them. While types of screw drivers are defined by tips that match the specific design of specific screw heads.

• A flashlight or mini flashlight is also one of the tools in computer troubleshooting. There are parts of the computer components that are too small in pieces and located in dark areas or some of electronic components that need to be checked and see the condition and its physical appearance.

• Grounding mat is a floor or table mat that reduces the risk of electrostatic discharge while working with electrostatic sensitive equipment especially electronic components that consist of electricity. 

• Compressed air is a combination of under pressure gases that are squeezed into a can. With computers and electronics, compressed air is the preferred method for removing dust and dirt from sensitive electronics. In this example, you would point the nozzle of the can in the direction you want the air to be blown and then squeeze the trigger.

• A multimeter (Alternatively referred to as a circuit analyzer, multi-tester, or VOM (Volt-Ohm-Meter) is a device used to test and measure current, voltage, and resistance. It also connects to a circuit using two (red and black/positive and negative) probes. 

• An antistatic bag is a packaging material that is specially designed to help prevent static electricity interacting with sensitive electronic components. These bags are made of plastic polyethylene terephthalate and often used to store and transfer electrostatic sensitive equipment. They come in many different sizes, from small bags for RAM chips to big bags for motherboards. Many antistatic bags have a silver color and are semi-reflective, while others are mostly clear and black, blue, or pink. 

• A lint free cloth is a special type of cleaning cloth that does not give up any fluff when used. Being free of lint means the cloth is less likely to build up a charge, which can cause Electro Static Discharge (ESD), damaging electronic equipment like High Definition (HD) televisions, computer monitors and digital cameras. 

• Solder is a metal alloy commonly comprised of tin or lead that melts when heated and allows a permanent connection to be made between electronic parts or wires. Some of electronic components of the computer are attached and soldered by this material.

• Tweezer is a small tool used for picking up too small objects to be easily handled with the human fingers especially small electronic component of the computer that is very sensitive to handle.

Appropriate Testing Procedures of the Electronic Components Safety First 

1. Electrical shock – Once you open up a set cover, you are actually exposing yourself to the threat of electric shock. Always keep in mind that safety comes first. A serious shock may stop your heart and if large electric current flows through your body, you will receive a serious burn and may cause death. So, don’t let yourself out of the mind that electronic components of the computer are just only a piece that will harm or kill you.

2. Discharging Switch Mode Power Supply - Before you start to work on a power supply, always turn off the power and discharge the electric charge inside. Most of electronic components of the computer have an electrical current not lesser than 400 voltage after turning off the machine, the current inside the electronic components are actively circulating inside the components. Always bear in mind that most of the time when you are touching any parts of the electronic components even after you turn off the power supply or unplug the power chord from the power source, some electronic components are still having electric current inside that can harm you.

3. Isolation transformer – When receiving any electronic equipment, always use an isolation transformer to protect yourself from electrical shock. During working, the isolation transformer is connected between the equipment and Alternating Current (AC) power line. 

4. High voltage – The high voltage circuit inside the computer components can give you a dangerous electric shock and cause you to injury condition. You could cut yourself by accidentally knocking on sharp chassis edges. Be familiar with the high voltage electronic components before testing and checking every single piece of electronic components of computer.

5. Wearing goggles – One of the most important Personal Protective Equipment (PPE) is the goggles. Wearing goggles while repairing, checking and testing computer is highly required, especially that computer consists of tiny pieces of electronic components that can harm your eyes.

6. Fire – Refrain from playing with the electronic components of the computer because every piece of the electronic component consists of high voltage of electricity that can cause fire or burning of components. 

7. Ventilation – Be sure that your working area has a good ventilation. Prolong exposure or excessive inhalation of vapors from a chemical element coming from electronic components can cause harmful effects to your health. 

Common Testing Equipment and Their Characteristics

Recording and Documentation of Your Result in Checking and Testing Electronic Components

Laboratory documentation, whether paper or electronic recording is an essential part of technical side. Required documents include laboratory’s policies, processes and procedures that generate results of development in testing or troubleshooting. 

1. Documents are used to check the product’s name, model and brand of the components where you want to test and use. It is important for you to establish familiarization of the components identity and description before you work on it. Every electronic component has their own capability and different standards of product.

2. Records provide evidence that the activities were performed. They contain details as to the timelines, processes involved and the results obtained.

3. Documentation is used to describe any policy, procedure, or manual log. It allows you to easily review and track the development of your previous activities.

4. Equipment/Tools maintenance proper maintenance, according to the manufacturer’s procedure is essential. It can give you information and idea whether the equipment/tools are ready to do a certain task and which tools are highly required to be replaced to enable you to purchase new tools to use. 

5. Inventory is an essential procedure in documentation process. It is the most important part to check the quantity of the tools which are repairable, replaceable and useful. 

Electronics test methods are integral to a variety of qualification plans, including product durability, safety and certification, and environmental testing programs. Element’s team of experts help design and implement test methods for virtually any electronic equipment, from automotive components to medical devices.

Working electronic components are crucial to operating virtually any electronic device. Components such as resistors, capacitors and transistors create circuits that allow TVs, stereos, cell phones and laptops to work properly. Each component has a specific role in a circuit. Resistors limit current. Capacitors store charge. Transistors amplify an electrical signal.

Appropriate Method for Testing Electronic Components

Troubleshooting with Multimeter 

We all know the rule and importance of “Troubleshooting” in Electrical and Electronics Engineering (EE). Most EE components and elements used in Electrical and Electronics equipment, devices and instruments are common in their functions and operations.

To be a good analyzer and troubleshooter, you must know the following basic techniques and has good skills in Electrical and Electronics troubleshooting, design and analyzing electric / electronic circuits. For this purpose, we have started a multimeter tutorial where we will use Digital Multimeter (DMM) and Meter Ampere-Voltage-Resistance Meter (AVO) or Multimeter (Digital/Analog) to test different electrical / electronic devices, instruments and components to find their terminals and condition such as are they short, open, good or faulty.

In this basic multimeter testing, we will use digital and analog multimeter to check the following electrical and electronic components, devices, tools and instruments: 

• Cables and Wires 

• Switch/Push buttons 

• Fuse 

• Capacitors and Inductors 

• Resistors and Burnt Resistors 

• Diodes and LED 

• Battery 

• Transistor 

• Relays 

In troubleshooting, we use different kinds of basic Electrical and Electronics Engineering Tools but the main and important tool is Multimeter. Now we will check the above mentioned components and devices with these tools one by one.

Cable and Wires 

Check if the cable and wires are in good condition or broken before sizing the proper cable & wire for Electrical Wiring installation, we perform the continuity test. For this purpose, take Digital Multimeter and select (“Resistance” rotate the knob to the “Ω” or Resistance).

Now connect both terminals, i.e. both naked ends of the cable/wire with the Digital Multimeter Terminals. If the meter reading shown “0 Ω”, it means Cable/Wire is in “Good Condition”. On the other hand, if meter reading is “Infinite”, it shows the cable/wire may be defected or broken. So, you need to replace it with a new one.

Switches/Push buttons 

Use the same method (mentioned above for checking the cable and wires)…to perform this method correctly, you will need to apply this method in both cases (ON & OFF positions) on switches and push buttons. In other words, first apply this method on switches/push buttons and then “Push” the push button and perform the same method again. 

At first attempt, if meter reading is “Zero” and in the second attempt, the meter reading is infinite, it means Switch/Push button is in good condition. If Multimeter reading is “Zero” or “infinite” in both attempts, it means switch is in short circuit or continuity connection is broken and you should replace it with a new one. 

Fuse To verify Fuse condition in good condition or damaged? We perform the same method I.e. continuity test as mentioned above. In short, if the meter reading is “Zero” it means Fuse is in good condition. If Multimeter reading is infinite, it means Fuse continuity may be broken or blown. So, you should replace it with a new one immediately.

Capacitor 

Here, we can check a capacitor with analog (AVO meter i.e. Ampere, Voltage, Ohm meter) as well as digital multi meter either it is in good condition or should we replace it with a new one. To find the value of Capacitance, you need a digital meter with Capacitance measuring features. 

Note: Not recommended for everyone but professionals only. Please be careful to do this practice as it is dangerous. Make sure that you are a professional electrical engineer / electrician (you really know that what are you doing or check the warnings before applying this method) and there are no other options to check the capacitor because serious damages may occur during this practice). If you are sure, go ahead, otherwise, go to method 2 – 6 as alternatively methods to a capacitor.

Step by step process for testing a Capacitor 

1. Disconnect the suspected capacitor from the power supply or make sure at least one lead of the capacitor is disconnected. 

2. Make sure that the capacitor is fully discharged. 

3. Connect two separate leads to the capacitor terminals. (Optional) 4. Now safely connect these leads to 230 V AC Supply for a very short period (about 1-4 Sec) [or for a short time where the Voltage rise to 63.2% of the Source Voltage]. 

5. Remove safety leads from the 230 V AC Supply. 

6. Now short the capacitor terminals (Please be careful to do that and make sure that you have wear safety goggles) 

7. If it makes a strong spark, then the capacitor is good. 

8. If it makes a weak spark, then it is a bad capacitor and change it immediately with a new one.

Diode and LED

Diode is a simple PN Junction and two terminal device which allow to flow current though it in one direction (Forward Bias). It is the most used component in different electronic designs and systems like rectifiers, LED lights related circuits, voltage multiplying circuits, solar panels, logic gates etc.

Before testing a diode, we must know the diode terminals like Anode (+) and Cathode (-). In most cases, there is a white band color coating on normal PN junction diodes which indicates as cathode terminal and the rest is anode. In other cases, there are different colors are used and the color coated sides are cathode as shown in fig below. Below is a tutorial that shows how to test a normal PN Diode, LED, and Zener Diode by different methods.

Transistor

A transistor, internally, is basically a component made up of different diode junctions. NPN and PNP Transistors are made up two pn junctions sandwiched together. These pn junctions are diodes. Knowing that transistors are essentially diodes sandwiched together (placed back-to-back), we can exploit this principle and test the leads of transistors as if they are separate diodes. If you want to learn more about diode testing. 

To test a transistor, we measure one diode junction with the multimeter leads situated one way and then we flip the leads of the multimeter to the reverse position, to switch polarity. One side of the diode junction should read a very high resistance, above 1MΩ of resistance (the anode-to-cathode side) and the other side should read a much lower resistance, maybe of a few hundred thousand ohms (the cathode-to-anode side). This we do for each junction.

Battery

There are lots of tools and meters to test battery, car battery and cells to check and measure the battery efficiency and condition. Although, we can test battery with digital millimeter, but for an almost accurate checkup, we may use special tools like Digital Battery Tester, Multi-Battery Tester, 12 Volt Electronic Battery & Starting/Charging System Tester, Electronic Battery and System Tester, etc. to check the battery state either is it good, or dead.

You will be able to find if the battery is in good condition, charged, need to be charge, low charge / current, high charge / current or is it faulty and need to be replaced with new one.

General Precaution  

• Disconnect the power source before checking, servicing, repairing or installing electronic equipment and devices.  

• Always, Select the higher value in Digital or analog Multimeter, and then, gradually reduce it to the proper valve  

• Never try to work on electricity without proper guidance and care  

• Read all instruction and cautions and follow them strictly.  

• Be careful because it’s all about electricity and electricity is too dangerous

Step by Step processing for Detecting and Recording problems/faults of the Electronic Components:

Step 1: Avoiding from Worst Case Scenario – Do not touch anything from electronic components/devices with proper guidance of the experts and professional to do if the components are already damage.

Step 2: Finding Electronic Components: Who does it and why it matters – Electronic components consist of electrical circuit can harm you or can kill you without the experts’ guide. Asking and finding experts to do some of guidance is a best solution before you engage in troubleshooting.

Step 3: Checking Electronic Components Handouts/User manual – All electronic components has always a User Manual for all client who purchased their product. It’s a basis for the client to check and read all important guide for the product.

Step 4: Identifying the problems of components – Basic checking and detecting of the problem in electronic components is important. By identifying its faulty result, you must observe proper safety measure to avoid accident while working. 

Step 5: Recording and Documenting – In finding the source of the problems, recording and writing down of the results is a needed thing for your guide. Recording is a process where every problem you detected is recorded what happened before and after testing.

Simple Techniques in Troubleshooting the Electronic Components:

Troubleshooting is a technique used for tracing out, identifying and fixing the most common problems that occur in an electronic component, resulting in its malfunctioning.

1. Confirm the Problem in the Circuit – start the troubleshooting process only after confirming the problem in the circuit, which may be about the desired results or improper working condition of the circuit. 

2. Consider Visual Inspection First – This step might be involved in getting physical contact with the circuit. So, it is required to perform safety measure procedure (Wear Personal Protective Equipment (PPE)) and most importantly remove the power supply to the circuit and wait for some time to discharge current in some components so that you can hold it without fearing. (Reminder: Please ask assistance or guidance from your parents/guardian to do so or much better you need to ask help from the experts before performing)

• Check the exploded or burn parts of the circuit by seeing and smelling (reminder: wearing proper goggle or mask to do this action is recommended)  

• Look for those loose, bad connection and also check the ground paths.  

• Check for the overlapped traces on the Printed Circuit Board (PCB).  

• Observe the soldered points whether they correctly soldered or not.  

• Check for the shorts or touches on the adjacent soldered points.

3. Select troubleshooting tools – troubleshooting process involves checking the terminal voltage across different component and devices in the circuit. 

4. Power up the Circuit – before checking with the above mentioned tools, plug the circuit to the main power supply so that it is possible to test it in different ways. (Note: Ask assistance to your parents/guardian before doing this. Never attempt to do this alone without prior knowledge about electrical knowledge)

5. Check the Power Supply Block – Keep the multimeter probes across the transformer, diodes, capacitor and regulator Integrated Circuit (IC), and check whether appropriate values are found or not by inserting the multimer in vols mode. (Note: Ask assistance to your parents/guardian before doing this. Ask guidance from experts to work this, never attempt to work alone)

6. Check the Individual Components – check the voltage across individual component, and if any component doesn’t show any voltage across it, then switch off the supply, and then try again to test the components by respective meters like multimeter for diode and so on.

7. Check the Main Controller – test the main controller base power supply with respect to the ground without placing controller on it. And also, check whether some pins are shorted or not special Integrated Circuits (ICs)

8. Check the Loads by Metered Power Supply – check the output by removing the main controller signal to final control device and apply metered-power supply so that the problem area can be easily recognized.

Standard is a technical document designed to be used as a rule, guideline or definition. Standards are created by bringing together all interested parties such as manufacturers, consumers and regulators of a particular material, product, process or service.

Industry standards are a set of criteria within an industry relating to the standard functioning and carrying out of operations in their respective fields of production. In other words, it is the generally accepted requirements followed by the members of an industry. It provides an orderly and systematic formulation, adoption, or application of standards used in a particular industry or sector of the economy. Industry standards vary from one industry to another.

A guide to Testing Electronic Components based on Industry Standards 

1. Power on the multimeter. Turn the knob to the resistance setting marked by the symbol for the Greek letter Omega. The knob setting should match the resistor value. If the value is unknown, start with the lowest setting and increase in gradual increments as you test the resistor.

2. Place a multimeter probe on each resistor lead. Check and take note the resistance. Switch probes and take note the resistance again.

3. Place the multimeter probes on other components leads. This can include diodes, capacitors and photocells. Attempt to measure the resistance using the same method as with the resistor. Photocells should be tested twice – near a light source and far away from that same light source.

Plan for electronic component testing based on industry standards 

• Identify various testing methods based on types of electronic components.  

• Determine different characteristics and appropriateness of testing methods to be used during development and on completion. 

• Select testing methods appropriate to testing strategy.  

• Develop testing plan methods for electronic components based on the industry standards.  

• Prepare and check test and measuring instruments and tools accordance with established procedures.  

• Establish record system to document testing results, including problems and faults.