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PCB Short Circuit

How to Prevent PCB Short Circuit?

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What is a Short Circuit in PCB?

PCB is a crucial part of electronics, and a short circuit can cause severe damage, which could be life-threatening. Addressing the problem of PCB short circuits requires proper maintenance techniques, while the design process precautions prevent future short circuit issues. 

PCB short circuit occurs when two or more conductive paths on the board accidentally come into contact. It creates a direct pathway for electrical current to flow in an unnecessary path, disrupting the circuit board. 

Reason for PCB Short Circuit

Short circuit finder

There are various factors that cause PCB short circuits. Below, we have explained these factors briefly:

Manufacturing Defects

During the assembly process, errors like component misalignments and soldering mistakes between the unnecessary connections on PCB paths could occur. This will lead to the flow of electric current in an unintended direction, resulting in a short circuit of the PCB. 

Environmental Factors

Exposure to dust, moisture, and other continuations can cause corrosion to the circuit board. It can change the conductivity in PCB, resulting in short curit over a long period.

This kind of PCB short circuit is also known as an electrochemical short circuit, where the ions residue on the circuit board. Here, PCBA undergoes various electrochemical migrations that reduce the life of electronic components. 

 

Electrical Static Discharge Breakdown

EDS is the process in an electronic system where components like capacitors and ICs are influenced by static electricity. Thus resulting in damage to IC devices.  This damage usually occurs when high voltage flows through these components from the electrostatic discharge, resulting in a short board circuit.

Thus, manufacturers should design PCBs to prevent ESD from burning out. In ElePCB, the following methods are implemented to avoid short circuits from EDS:

  • Use of capacitors of high voltage ratings
  • Use of avalanche diodes for preventing the electrostatic short circuit. 
  • Use of CMOS or TTL devices
  • Adding filter-type LC helps prevent the risk of high-frequency static electricity. 

Improper Soldering

It is the next major case of PCB short circuit. The soldering short circuit is caused by compactly placing the IC pins or too small gaps between the components.

It usually happens when the stencil’s thickness in solder paste printing and the hole’s size is not set correctly. It results in excessive solder paste, which causes a short circuit of the board.

Aging and Wear

Over time, PCB materials may degrade, which results in increased susceptibility to short circuits in high temperatures and high humidity.

Effects of PCB Short Circuit

reflow soldering process

When a PCB experiences a short circuit, it can have several effects, including:

  1. Malfunctioning Circuits: PCB Short circuit disrupt the normal flow of electricity within the PCB. It causes circuits to malfunction or stop working altogether.
  2. Component Damage: The excess current flowing through the short circuit can damage electronic components such as resistors, capacitors, and integrated circuits.
  3. Risk of Fire or Electrical Hazards: Short circuits can generate heat due to the increased current flow. Thus, it leads to overheating and even fires in extreme cases. This poses a risk of electrical hazards and safety concerns.
  4. System Failure: In critical electronic systems, a PCB short circuit can lead to complete system failure. It results in downtime, loss of data, and potentially costly repairs or replacements.

Unpredictable Behavior: Short circuits can cause irresponsible behavior in electronic devices. It causes unexpected shutdowns or damage to other connected components.

Find and Test the Short Circuit in the PCB

In ElePCB, we implemented various approaches to testing the PCB for short circuit. Let’s look into some of the commonly used methods to test and detect the Short Circuit in PCB:

Visual Inspection

PCB Visual Inspection

The first step to finding the PCB short circuit is looking into the PCB surface. It is also known as manual inspection. You must use a microscope or magnifying glass with appropriate magnification during the examination. You can start troubleshooting with the power supply points to make tracking the circuitry’s damage easier. 

Look around solder, as it can also cause short circuits. Burn scares around the components show there has previously been a shortage. 

Also, check the vias. Make sure there are no un-plated vias in your design if needed, and ensure that plated vias are solid. Inadequately plated vias can cause short circuits and potentially damage the entire board.

Digital Multimeter

Digital Multimeter for testing short circuit

So, if you can’t examine your circuit board through visual examination, then use the multimeter. Try to identify the short circuit location on the PCB. A multimeter can provide the idea of the starting point of a short circuit on PCB. 

As before, always start from the power supply point and test each trace and pad. Usually, there is a high resistance reading in neighboring connections. But if you encounter a low reading, there is a change of short circuit. 

Again, if you didn’t find any issue in neighboring joints, start testing on unconnected circuits and check for any readings between the circuits that will show the bridging. 

Thermal Camera

Thermal Inspection PCB

The use of thermal cameras might only be affordable for some companies. However, it can provide the exact point of the short circuit. A short circuit in PCB generates the heat, and the thermal camera can use that heat to pinpoint the issue on board. 

You must turn on the power and check for the much hotter components or solder joints. Those are the point of the issue.

Testing Individual Components

PCB Component Testing in PCB Quality Contorl

Using multimeter, each component and parts of PCB can be checked for short circuit issue. This could be somehow hectic for large and complete circuit boards. However, it will help to ensure the issue is not in components since it is hard to predict it before installing the components. 

Sometimes, the board’s layout can be problematic, as the close components could lead to short circuits. 

For this, measure the resistance reading on every component pad and pin and ensure they work correctly. You can check the pads and pin connections if you see no issues.

In-Circuit Testing

In-circuit testing

It is one of the most valuable tools for identifying the PCB short circuit. It is a specialized tool for examining the electrical characteristics of components concerning the board. It helps to detect the PCB short circuit quickly without any effort.

How to Prevent PCB Short Circuit

Short Circuit in PCB is one of the significant problems in circuit boards. Manufacturers try their best to prevent these issues. Let’s look into some of the best practices to prevent the circuit board from short circuit:

PCB Design Best Practices

It’s vital to effectively follow the best practices for PCB design to prevent PCB short circuit during the design phase. One critical aspect is ensuring proper separation between components. A crowded board can lead to short circuits when components are too close to different tracks.

PCB design encompasses various crucial steps. Ensuring proper insulation between traces is paramount to avoid short circuits caused by proximity. Designers should also ensure the power supply provides enough power without overloading the PCB.

PCB Maintenace Best Practices

PCB maintenance plays a crucial role in the long-term reliability and durability of the device. It is one of the essential considerations. Regular inspections and cleaning can avoid the problem of short circuits. 

The next important thing is to use the proper tools and techniques to clean the PCB. PCBs are susceptible devices, and using the wrong tool can cause harm to the system. 

Besides, using proper cleaning products can help protect the components. 

 

Testing and Troubleshooting Best Practices

Testing the PCB is essential to resolve the short circuit in the PCB. Multimeters are the most reliable tool that can be used to troubleshoot PCBs. It checks the continuity between various areas on the board and identifies the incorrect connections present. 

Following the standard process and measuring when you troubleshoot the PCBs is essential.

Start with the power supply and test each component separately. That will help to find the short circuit more quickly.

Conclusion

Finding and fixing the PCB short circuit requires an approach and strategy based on design maintenance, troubleshooting, and testing. If you consider the best design practice for PCB design and maintenance, you can reduce the problem of short circuits. If you encounter an issue on your PCB, use the proper tools and techniques to test.

When you are inspecting your PCB, try to follow the safety guidelines. Always pay proper attention from manufacturing to design and use processes to prevent PCB short circuits.

CONTACT ELE

ELE PCB has got the IS09001:2015, IS013485:2016, ROHS and FCC certifications. We can offer all kinds of services, including PCB manufacturing and PCB assembly, sample orders and batch orders. For PCB assembly, utilizing 7 high-speed SMT PCBA lines from Yamaha and Sony, to meet our customers’ needs. Our extended services include PCB design &PCB Layout, hardware design engineering, firmware &software development, and personalization. ELE company is honored as an excellent supplier from any company all around the world. We deeply believe that our good service and experience will completely meet your needs. Integrality, value and innovation are the forces that drive our success.

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About the Author
Rashila
I am an Electrical and Electronics Engineer, and I have 5 years of work experience with electronics and communication jobs. I'm the full time content creator of ELE company.
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