Wave Soldering

Wave soldering is a bulk soldering process used in the manufacture of printed circuit boards. It is used for both through-hole printed circuit assemblies, and surface mount. However, wave soldering problems is common during a PCB fabrication process. 

This can be caused by a variety of reasons and the primary one which comes to our mind in the first time is bad plated through-hole barrels. So check the plating in the barrels to make sure there are no voids is very crucial in a wave soldering process. Voids will have a tendency to create outgassing and this creates voids in the solder joints.

The other issue is to bake the boards to expel moisture trapped in a PCB. Great experience in successfully eliminating voids by pre-baking boards and storing them in vacuum sealed bags is really useful. You should know that once a board is baked, if left out in the open air, it will reabsorb 75% of the moisture you just baked out of it within 48 hours. So before wave soldering, make sure the moisture of your board could be as lowest as possible, or you can find voids appeared.
More info. about PCB soldering, pls visit www.epcb.com

Solder Bridge

A bridged solder joint is formed by melting two solder joints together, forming an unintended connection between the two. The spacing between connections is quite tight, so you can easily bridge across two terminal connections. You can check by testing for shorts between each connection or use a magnifying glass to visually examine the connections.

You can avoid this only by using enough solder to make a good joint, because solder bridges often happen between joints with too much solder to begin with. If you have to tackle the solder bridge, it is not difficult. Sometimes the excess solder can be drawn off by dragging the tip of a hot iron between the two solder joints. If there is too much solder, a solder sucker or solder wick can help get rid of the excess.

More tips about soldering, welcome to www.epcb.com

A Broken Solder Pad

This is a common problem, especially when re-doing wiring. A combination of heat and the physical stress of removing a wire can cause the copper pad to break away from the copper trace leaving a fine gap between the two. The best way to check this is to use a multimeter to check a gap between the pad and the destination of the connection. Follow the trace from where the pad connects to another visible connection point. These can usually be repaired by taking an ink eraser and rubbing down the trace right by the pad to expose base copper and then heating the existed solder and use the iron's tip to drag the molten solder out over the exposed copper of the trace to make the connection. Recheck with the multimeter to validate that you not have a connection from pad to destination of trace. If the gap is significant, use a piece of fine bared wire to bridge the gap and then solder a trace and a joint is a good choice.

To avoid the above problem, you'd better read more about soldering on www.epcb.com

Disturbed Solder Joint

What is a disturbed solder joint? This is an interesting and difficult question to answer. To simplify, the formation of a disturbed solder joint happens during the solidification process of the alloy. When alloys are in their molten state their surface appearance can be easily affected by outside mechanical influences.

Major cause for the formation of a disturbed solder joint is usually due to some outside vibration of the assembly during the cooling process. Another is easily caused by operators. Reaching into a system and removing an assembly prior to the solder joints ability to solidify, or the PCB transferring from one conveyor to another while the alloy remains in the liquid state. It is the movement of the assembly while the alloy is in the liquid state that creates a disturbed solder joint. 

If you solder a disturbed joint by mistake, it doesn’t matter because the joint can be repaired by reheating and allowing it to cool undisturbed. in addition, you can prevent it by prepare properly which includes immobilizing the joint and stabilizing the work in a vise.
More info. about soldering, welcome to www.epcb.com

Insufficient Wetting

Wetting is the ability of a liquid to maintain contact with a solid surface, resulting from intermolecular interactions when the two are brought together. The degree of wetting (wettability) is determined by a force balance between adhesive and cohesive forces. Wetting is important in the bonding or adherence of two materials. So what’s the result of insufficient wetting? Here EPCB lists 3 examples. 

Insufficient Wetting (Pad): Suppose a solder has wetted leads nicely, but it has not formed a good bond with the pad. This can be caused by a dirty circuit board. 

Insufficient Wetting (Pin): If a solder in a joint has not wetted the pin at all and has only partially wetted the pad. In this case, heat was not applied to the pin and the solder was not given adequate time to flow.

Insufficient Wetting (Surface Mount): Assume that we have three pins of a surface mount component where the solder has not flowed onto the solder pad. We can heat the solder pad with the tip of the iron, then apply solder until it flows and melts together with the solder already on the pin.

More info. about printed circuit board soldering, welcome to www.epcb.com

Cold Solder Joint

Cold solder means the solder is more or less in the right place, but isn't actually bonded to one or more of the metal surfaces in the joint, so the solder bond will be poor and the cracks may develop in the joint over time. A cold joint is one where the solder did not melt completely. Thus, it is unreliable and often characterized by a rough or lumpy surface. It can also happen when you're soldering materials that haven't been prepared for soldering. For example, bare aluminum is a real pain to solder.

To prevent cold joints, make sure every surface you want to solder is actually being heated to the melting point of the solder. If you're using a soldering iron, it should touch every metal surface in the joint. Don't use the iron to melt the solder. Wait for the heated surfaces to melt it. 

If you still find cold solder joints on you circuit board, don’t worry. They can usually be repaired by simply re-heating the joint with a hot iron until the solder flows. Many cold joints also suffer from too much solder. The excess solder can usually be drawn-off with the tip of the iron.

More info. about solder, pls visit www.epcb.com

E-Waste

E-waste or electronic waste is the left over PCBs, components, PVC or plastic cases, body, etc., of your old electronic appliances, such as a TV, refrigerator, dish washer that you have thrown out. It is one of the fastest growing types of waste produced on the planet. According to a report on e-waste, by 2017, all of that year’s end-of-life refrigerators, TVs, mobile phones, computers, monitors, e-toys and other products with a battery or electrical cord worldwide could fill a line of 40-ton trucks end-to-end on a highway straddling three quarters of the Equator, the weight equivalent of 200 Empire State Buildings or 11 Great Pyramids of Giza. The US has the world’s highest figure of 9.4 million tons and China generated the second highest e-waste total of 7.3 million tons. The report also states that the total amount of e-waste generated by 2017 will be 65.4 million metric tons.

What can we do to stop the severe situation? Well, the simple answer is stop over-consumption. But that could take a long time to actually come into action. The next big thing is too start recycling every bit of those electronic appliances and gadgets that our leaving our house. We can open up the body of each of these appliances take out the PCBs and reuse the components.

Learn how to reuse printed circuit boards, welcome to www.epcb.com

Positive, Negative and Neutral Wires Color

Color codes for wires helps ensure easy and proper identification of the wire types and safety precautions required. The color of wires is dependent on the method of wiring and where one is located. In the United States, a common two-wire ungrounded circuit has a red positive wire and a black negative wire. For a two-wire system with a negative ground, the positive wire is red, and the negative wire is white. For a two-wire system with a positive ground, the positive wire is white, and the negative wire is black. 

As to the neutral wires, the U.S. National Electric code and Canadian Electric Code mandates only white or grey color be used. The International Electrotechnical Commission and countries that abide by it, such as the United Kingdom, use blue for the wiring color code for neutral wire of AC branch circuit. A neutral wire in AC power provides a low-impedance path to earth or ground to prevent passage of heavy voltage through the equipment. 

Read more, pls visit www.epcb.com

Half Wave Rectifier

A half-wave rectifier is an electronic circuit, and a type of rectifier that rectifies only half cycle of the waveform. It gets its name from the fact that only half the sine wave of the alternating current passes through it and is converted to direct current. The half-wave rectifier consist a step down transformer, a diode connected to the transformer and a load resistance connected to the cathode end of the diode. 

The main supply voltage is given to the transformer which will increase or decrease the voltage and give to the diode. In most of the cases, the step-down transformer is used to decrease the supply voltage. This decreased alternating current voltage is given to the diode which is connected serial to the secondary winding of the transformer, diode is electronic component which will allow only the forward bias current and will not allow the reverse bias current. 

More about rectifier, welcome to EPCB.

Rectifier

Rectifier is an electronic device which converts the alternating current to unidirectional current, in other words rectifier converts the alternating current voltage to direct current voltage. The process is known as rectification. Physically, rectifiers take a number of forms, including vacuum tube diodes, mercury-arc valves, copper and selenium oxide rectifiers, semiconductor diodes, silicon-controlled rectifiers and other silicon-based semiconductor switches. You can find rectifier in almost all the electronic devices because rectifier can convert the main voltage into direct current voltage in most power supply part, and every electronic device will work on the direct current voltage supply only. Rectifiers are classified according to the period of conduction. They are half wave rectifier and full wave rectifier. 

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Test Circuit for Machine Model

The configuration is similar to the human body model except for the discharge resistor, which was replaced by an inductor. This is because charged metal parts in machines have very low resistances. A well-known consequence of not having a discharge resistor is uncontrolled current. No control over current transients results in unknown rise times that allow bypass of ESD protection and destruction of the DUT (at voltages near 500 V). This is one reason why the machine model has lost its popularity. The charged-device model arises due to ESD during PCB mounting of the integrated circuit. It took a tedious investigation to prove this phenomenon, where the integrated circuit gains charge as it slides along the plastic rails of the production line and discharges upon touchdown on the PCB. 

More info. about test circuit, welcome to www.epcb.com

How ESD Affects Semiconductor Devices and Circuits

Before learning more complicated testing procedures, know what’s happening when semiconductors are subjected to ESD is very important. ESD can damage devices by a rapid localized heating of the semiconductor material or by rapidly creating strong electrical fields. Critically, even very small discharges or over-stress can be fatal or cause latent failures. The manufacture of semiconductor circuits not only involves components that were intentionally made, but also those that come as a consequence of the circuit’s construction and architecture. These components play crucial roles in circuit design and analysis, and usually cause damage of an IC. Some examples would be the capacitances between junctions that form an electrical short to high-frequency components and the parasitic thyristors between transistors that form an electrical short when activated.
More info. about ESD, pls visit online website by EPCB

Choose the Best Microcontroller

A microcontroller is a self-contained system with peripherals, memory and a processor that can be used as an embedded system. Most programmable microcontrollers that are used today are embedded in other consumer products or machinery including phones, peripherals, automobiles and household appliances for computer systems. Microcontrollers are so powerful components that they let you write programs to control your electronics. 

There are lots of choices when you want to choose a best microcontroller. If you want something simple, probably an 8-bit microcontroller is a good choice. EPCB lists 5 easy tips for you to select your microcontroller. They are simple architecture and easy to learn, currently being used in modern designs, the availability of an evaluation module or an applications board, something individual hobbyists and experimenters can buy, and free or cheap software. If your microcontroller meets all the criteria, then you may find your best microcontroller. 
More info., welcome to www.epcb.com

Microcontroller Basics

A microcontroller is a self-contained system with peripherals, memory and a processor that can be used as an embedded system. Unlike microprocessors that can be found in PCs, microcontrollers are designed to be used for embedded applications, so they are used in automatically controlled devices including power tools, toys, implantable medical devices, office machines, engine control systems, appliances, remote controls and other types of embedded systems. 

There are two ways of using microcontrollers in a project, one is to use a microcontroller board, and another is to integrate a microcontroller on your circuit board. The simplest way for hobbyists to get started is to use a microcontroller board. The most famous microcontroller board is Arduino. It’s a hardware and software suite designed to make it easy to get started with programming microcontrollers. But you can also find other microcontroller boards. They usually have just the microcontroller chip and the necessary components to make it work. 
More info. about microcontroller, pls visit www.epcb.com

PIC Microcontroller

There are many types of microcontrollers available on the market. Some are easier to use than others. There are 8-bit, 16-bit and 32-bit microcontrollers available. The simplest microcontrollers are 8-bit. PIC microcontroller is one of the easiest 8-bit types for hobbyists and beginners to use. PIC is a family of modified Harvard architecture microcontrollers made by Microchip Technology, derived from the PIC1650 originally developed by General Instrument's Microelectronics Division. The name PIC initially referred to Peripheral Interface Controller. The first parts of the family were available in 1976. Early models of PIC had read-only memory for program storage. All current models use Flash memory for program storage, and newer models allow the PIC to reprogram itself. PIC devices are popular with both industrial developers and hobbyists due to their low cost, wide availability, large user base, extensive collection of application notes, available of low cost or free development tools, serial programming, and re-programmable Flash-memory capability.
More info. about microcontroller, welcome to www.epcb.com

AVR Microcontroller

There are many types of microcontrollers available on the market. Some are easier to use than others. There are 8-bit, 16-bit and 32-bit microcontrollers available. The simplest microcontrollers are 8-bit. AVR microcontroller is one of the easiest 8-bit types for hobbyists and beginners to use. AVR is the microcontroller that really popular among hobbyists. The AVR is a modified Harvard architecture 8-bit RISC single-chip microcontroller, which was developed by Atmel in 1996. And the AVR 8-bit microcontroller architecture was introduced in 1997. The AVR was one of the first microcontroller families to use on-chip flash memory for program storage. High reliability, high speed, low power consumption and low price, have been an important measurement to evaluate the performance of the AVR microcontroller, and become the necessary conditions for it to occupy the market.

More info. about microcontroller, pls visit www.epcb.com

Microcontroller

A microcontroller is a self-contained system with peripherals, memory and a processor that can be used as an embedded system. Most programmable microcontrollers that are used today are embedded in other consumer products or machinery including phones, peripherals, automobiles and household appliances for computer systems. Microcontrollers are so powerful components that they let you write programs to control your electronics. 

There are several different kinds of programmable microcontrollers. The most common types categorized by several parameters including Bits, Flash size, RAM size, number of input/output lines, packaging type, supply voltage and speed. Programmable microcontrollers contain general purpose input/output pins. The number of these pins varies depending on the microcontroller. They can be configured to an input or an output state by software. When configured to an input state, these pins can be used to read external signals or sensors. When they are configured to the output state, they can drive external devices like LED displays and motors.
More info. about microcontroller, welcome to www.epcb.com

Inductor

An inductor, also called a coil or reactor, is a passive two-terminal electrical component which resists changes in electric current passing through it. It is just a coil of wire around some kind of core. Energy is stored in a magnetic field in the coil as long as current flows. The inductor is a wire shaped so that the magnetic field will be much stronger. When the current flowing through an inductor changes, the time-varying magnetic field induces a voltage in the conductor, according to Faraday’s law of electromagnetic induction. The reason an inductor works the way it does is because of this magnetic field. This field does some magic physics stuff that resists alternating currents.

More info. about inductor, welcome to www.epcb.com

Surface-mount Technology

Surface-mount technology or SMT is a method for producing electronic circuits in which the components are mounted or placed directly onto the surface of printed circuit boards (PCBs). In PCB industry it has largely replaced the through-hole technology construction method of fitting components with wire leads into holes in the circuit board. Surface-mount technology has several competitive advantages, and they are listed as follows:

1. The cost of surface-mount technology can lower 30%~50% than other technologies from saving materials, energy, equipment, labor, time, etc.

2. The efficiency of SMT can easily be increased by using auto machine. 

3. SMT has good high-frequency performance which can largely reduce the interference of radio-frequency and electromagnetism. 

4. SMT is more reliable that it has high resistance capability, and low soldering defect rate. 

More info. about SMT, pls visit www.epcb.com

LED

A light-emitting diode (also known as LED) is a two-lead semiconductor light source. When a suitable voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the color of the light is determined by the energy band gap of the semiconductor. There are a few different LED types. Here we give a brief introduction about LED color.

Single color: A single color LED means one color only. The color of the light is usually reflected in the color of the plastic housing, but not always. It is powered by connecting the positive voltage terminal to the anode and the negative to the cathode. An LED should always have a current limiting resistor. The most common single-color LEDs are: red, orange, yellow, green, blue, white.

Multi-color: A multi-color LED is actually capable of generating many colors (more than one) within itself. The most common LED is known as RGB LEDs which involves red, green and blue color. This technology is well used by the motherboard manufacturer, to show the power indication. For example, red means lower power than the recommended rating while green means full power. 
More info. about LED, welcome to visit www.epcb.com

Resistor Types

Resistors can be made of several different materials and methods. Here are a few types of resistor: lead arrangements, carbon composition, carbon film, carbon file, printed carbon resistor, metal film, thick and thin film, metal oxide film, foil resistor, wire wound, foil resistor, ammeter shunts and grid resistor. Different types have different features. Some are very accurate, some can withstand high temperatures, some can withstand high power, and some are cheap. Some are good for low noise applications, and some are good for high-power applications, for high-speed applications and for measurement circuits.

You don’t need to learn more all features of each resistor type if you need standard circuit board. What matters you is about the resistance value and how much power it can take. If your schematic does not tell you the necessary power rating for the resistor, and you don’t know how to calculate it, then you may try a standard 1/4W resistor. If it fails after a short while, you can exchange it for a higher wattage rating.
You can learn more about resistors from www.epcb.com

How a Relay Works

A relay is an electromechanical switch. It works in the same way as a manual switch. It is very useful not only for turning the power of a device on and off automatically but also for switching higher power devices with a low power. 

An electromagnet is a simple device made up of a wire wound in a coil around a core of ferromagnetic material. To create your own electromagnet, a nail and some insulated wires are enough. Wind the wire into a coil around the nail and apply power. Attention, it can be very hot if you have too few windings or too much voltage!

When a wire conducts current, it produces a magnetic field. If we wind a wire into a coil around a core of ferromagnetic material such as iron, we magnify this field and we get an electromagnet with enough magnetism to do some interesting stuff.

Notes of caution: Always check the voltage and current rating of the relay switch. Some are designed for switching low voltages only, while others are meant for switching higher voltages.
More info., welcome to www.epcb.com

How to Desolder a Solder Joint

To know how to desolder a solder joint sometimes is as important as know how to solder. You may need to make a correction to your electronic circuit during processing. Maybe you soldered a component in a wrong location or maybe two of your pads have accidentally been connected by some extra solder. Under these circumstances, you need to know desoldering.

You can desolder with a solder sucker, a solder wick, or even without any desoldering tools. The third one looks amazing, and here we give a brief introduction about its procedure. Suppose you need to remove extra solder bridge between two pads, just heating the solder joints and then poking around with the tip of the iron until the bridge is gone. However, we don't recommend this method unless you have no solder suck, solder wick or any other alternative. Finally, we find that a solder wick is sometimes much easier to use when you are dealing with smaller pads and pins.

More tips about desoldering, please visit www.epcb.com

Soldering Safety Tips

While soldering is not generally a hazardous activity, there are a few things outlined by EPCB for you to keep in mind.

Solder, flux and cleaners: Always use rosin and lead -free solders. Always wash your hands with soap and water after soldering.

Lead exposure: Lead can cause serious chronic health effects. Exposure will indirectly hurt your skin, wear gloves if directly handling solder.

Rosin exposure: Rosin is a resin contained in solder flux. Flux always generates fumes during soldering. Exposure to rosin can cause eye, throat and lung irritation, nose bleeds and headaches. Always exposure can cause respiratory and skin sensitization, causing and aggravating asthma.  

Control of fumes: Only there is no other good alternative, can manufacturers use rosin during soldering. Fumes should be vented to the outside properly and immediately. 

Training and supervision: Supervisors/line managers should inform users of the risks from soldering, and ensure that all workers can solder appropriately.

The Most Common Components

Today EPCB tries to give a brief introduction to how common electronic components work. They are resistor, resistor, diode, transistor and integrated circuit.

Resistor: A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. Resistors may be used to reduce current flow, and, at the same time, may act to lower voltage levels within circuits. Resistors are ubiquitous in electronic equipment, and maybe it is the most common one among all electronic components. 

Capacitor: A capacitor is a passive two-terminal electrical component used to store electrical energy temporarily in an electric field, and ideal capacitor does not dissipate energy.

Diode: A diode is a component that only conducts electricity in one direction. Today, most diodes are made of silicon 

Transistor: A transistor is similar to a relay in the sense that you can use it to turn on and off a current. It is a semiconductor device used to amplify or switch electronic signals and electrical power. It is a fundamental component in both modern electronic devices and modern electronic systems.

Integrated Circuit (IC): An integrated circuit (also referred to as an IC) is a circuit made up of several tiny components and placed in a small package. It could be anything from a microcontroller to a radar system.

PCB Design Guidelines

Here are some simple PCB design guidelines that can help you create better board layouts.

Board size: There are always limits to how big your board can be, how thin your traces can be and the smallest drill size you can use. You can visit your PCB manufacturers’ website to check their capabilities. You should keep those data in your mind when you design a new board

Trace width: It must be at least the size of the smallest allowed trace width, but should generally be thicker because thin traces are more vulnerable to damage when soldering. The more current that is going to flow through the trace, the thicker it should be. 

Placement of components: Place your components in a similar way is easy for you to troubleshoot your circuit. When place your components, pay great attention to your large components and connectors.

More PCB design guidelines, please visit www.epcb.com

Soldering Tips

Soldering is an important skill. No one can solder the components perfectly every time, so we neef to practice more. The following tips should help you to learn more about how to correctly solder so as to avoid some unnecessary damage. 

1.Use heatsinks. Heatsinks are a must for the leads of sensitive components such as ICs and transistors. If you don't have a clip on heatsink, then a pair of pliers is a good substitute.

2.Keep the iron tip clean. A clean iron tip means better heat conduction and a better joint. You’d better to use a wet sponge to clean the tip.

3.Double-check joints. When assembling complicated circuits, it is good practice to check joints after soldering them. You can use a loupe to check the joint and a meter to check the resistance.

4.Solder small parts first. Solder resistors, jumper leads, diodes and any other small parts before you solder larger parts like capacitors and transistors. This makes assembly much easier.

5.Install sensitive components last. Install CMOS ICs, MOSFETs and other static sensitive components last to avoid damaging them during assembly of other parts.

More info. about soldering tips, pls visit EPCB.

Why Use Surface Mount Devices?

SMDs have improved performance over through-hole components due to their smaller size, shorter internal leads, and smaller board layouts. SMDs can also be more cost effective than traditional through-hole components due to the smaller board size, fewer board layers, and fewer holes. Besides, they are easier for people to replace than through-hole components on multilayer boards. The reason is because it is very difficult to heat the long hole on a multilayer board, but much easier to heat just the pad and component terminal of an SMD on the surface of a board. SMD components have a variety of advantages than through-hole components. 

1.The cost of surface-mount devices can lower 30%~50% than other technologies from saving materials, energy, equipment, labor, time, etc.

2.SMD has good high-frequency performance which can largely reduce the interference of radio-frequency and electromagnetism. 

3.SMD is more reliable that it has high resistance capability, and low soldering defect rate. 

4.Products are always 40%~60% smaller and 60%~80% lighter than using other methods.

For more info. about surface mount articles, pls visit Shanghai EPCB.

Soldering a Surface Mount Resistor

There are several ways to successfully solder SMD components on a circuit board. Some are easier to learn, and some require using special materials (like solder paste, which is a mixture of powdered solder and flux) or special equipment (like SMD solder stations). Actually, you don’t need fancy equipment to do SMD soldering at home. You can easily do it with a soldering iron.

Soldering a resistor is the simplest way for freshmen. At the beginning, you should apply flux to one pad on the circuit board in order to clean the pad and make it easier for the solder to fasten properly. And then touch the circuit board pad with the tip which covers some solder to let them pass on to the pad. Next, place the resistor on its ideal location, and fix it by soldering. The resistor should now be fastened on one side. Apply solder to the soldering tip again and touch the iron tip on the other side. Finally, you’d better to use a loupe to check the solder joints to make sure the connection is good. 

More info. about soldering, pls visit Shanghai EPCB

Soldering Surface Mount Chips

There are several ways to successfully solder SMD components on a circuit board. Some are easier to learn, and some require using special materials (like solder paste, which is a mixture of powdered solder and flux) or special equipment (like SMD solder stations). Actually, you don’t need fancy equipment to do SMD soldering at home. You can easily do it with a soldering iron. 

If you are able to solder a resistor, it won’t be difficult for you to solder a surface mount chip as the method is similar. Start by applying some solder to one of the chip’s corner pads. Secondly, hold the chip in place while touching the corner pad with the tip of the soldering iron so that the heated solder can combine the pin with the pad. Next, check the alignment of the chip. If it is not in its place, then relocate it. Only you’re sure the chip place is perfect, can you move to the next step. Then you can solder on the opposite corner just like the one you have fixed. Finally, after all the pins have been soldered, you should inspect all the solder joints carefully with a loupe to check if there exist any bad joints or solder bridges. 

For more info., pls visit Shanghai EPCB.

ICT Disadvantages

Every coin has two sides, though in-circuit test is a very powerful tool for testing PCBs, the in-circuit test also has some disadvantages which are listed as following. 

1. As the fixtures are mechanical and require general and wiring assembly for each printed circuit board, they can be a costly item.

2. As the fixture is a fixed mechanical item, with the probes or "nails" mechanically fixed, any updates to the board changing the position of the contact points can be costly to change.

3. Electrolytic components can be tested for polarity only in specific configurations (e.g. if not parallel connected to power rails) or with a specific sensor

4. The quality of electrical contacts cannot be tested unless extra test points or a dedicated extra cable harness are provided.

5. It is only as good as the design of the PCB. If no test access has been provided by the PCB designer then some tests will not be possible. 

Foe more info., pls visit Shanghai EPCB.

ICT Advantages

In-circuit test is a very powerful tool for testing custom PCBs which has several advantages. When determining the best form of test for any given application, it is necessary to investigate the advantages of each system carefully.

Easily detect manufacturing defects: It is that most board faults arise from problems in manufacture - incorrect component inserted, a wrong value component, diodes, transistors or ICs inserted with incorrect orientation, short circuits and open circuits. These are very easily and quickly located using ICT as the in circuit tester checks components, continuity, etc.

Programme generation is easy: An In-Circuit tester is very easy to programme - files can be taken from the PCB layout to generate much of the programme required.

Test results easy to interpret: As the system will flag a particular node as having a short of open, or a particular component as being faulty, location of a problem in a board is normally very easy - and do not require the application of the most highly skilled test staff.

For more info., pls visit Shanghai EPCB. 

Capacitance and Resistance Tests

To guarantee the high-quality of finished printed circuit boards produced by us, Shanghai EPCB will test capacitance and resistance of PCBs before shipping them for you to use. Capacitance testing for bare circuit boards involves charging a net or plane before probing each net to measure the induced capacity. Inaccuracies do occur with this method due to inherent variability in producing PCBs. Resistance testing measures the resistance found in the net, which is proportional to length and inversely proportional to the cross-sectional area of a conductor. A good conductor will have a low resistance. Only all PCBs pass the capacitance and resistance test can we deliver goods to you.

Potential Applications for Soluble Printed Circuit Boards

Though soluble printed circuit boards can greatly protect our environment, product designers and engineers in all industries must find ways to integrate the technology into our daily applications, so they can enter the market and accept by people all around the world. Potential uses for this new technology that could be seen in the coming years include: 

Medicine – Brain monitors and other medical devices that need to be implanted can be made from these components so that once they have served their purpose they do not need to be removed.

Cell Phones – Most cell phones and other portable electronics end up in landfills when people stop using them, but it really does severe harm to our environment. If we use soluble printed circuit boards, they will be able to safely and responsibly recycle.

Machinery – Machines that rely on PCBs can have their parts easily swapped out as needed without needing to start from scratch, saving time and money. 

For more info.,  pls visit the website of  Shanghai EPCB.

Laser Cutting

Laser cutting is a type of subtractive manufacturing that cuts a digital design file into a piece of sheet material. It is typically used for industrial manufacturing applications, but is popular among schools, small businesses, and hobbyists right now for its easy using and excellent results. A computer directs a high-power laser at the material. The material then melts, burns or vaporizes leaving an edge with a high-quality finish. A typical commercial laser for cutting materials would involve a motion control system to follow a CNC or G-code of the pattern to be cut onto the material. There are many different methods in cutting using lasers, with different types used to cut different material. Some of the methods are vaporization, melt and blow, melt blow and burn, thermal stress cracking, scribing, cold cutting and burning stabilized laser cutting. 

For more info., please visit Shanghai EPCB.

PCB Depanelization

Depanelization is the removal of the PCBs from the panel itself. In order to increase the throughput of printed circuit boards manufacturing, PCBs are often designed so that they consist of many smaller individual PCBs that will be used in the final product. This PCB cluster is called a panel. The large panel is broken up or "depaneled" as a certain step in the process - depending on the product, it may happen right after SMT process, after soldering of through-hole elements, etc., but it often occurs before final assembly and testing takes place. There are six main depanelization cutting techniques currently in use: hand break, pizza cutter (also known as V-cut), punch, router, saw, and laser. For more information, please contact a representative of Shanghai EPCB. 

Soluble Printed Circuit Boards

The mobile devices are so common in people’s daily life as the economy picks up. It is said that Ringing Bells in India has launched a $4 mobile phone which indicates a dramatic growth in PCBs use. But we cannot ignore a serious question about how to tackle those consumer electronics and other products when they are no longer in use? Of course, they can’t be dropped in landfills which have a drastic bad effect on our environment. Researchers are working to tackle this problem by developing printed circuit boards that are soluble and will essentially dissolve completely over time. This technology is primarily aimed to assist the medical industry, but would also do wonders for the world of consumer electronics. There is still much to be developed and worked out in terms of ensuring that components work the same, if not better, than what is available now.

To protect our environment, Shanghai EPCB always firmly comply with the requirements of RoHS compliant and IPC-A-600H-2010 in PCB manufacturing process, as well as any other requirement of the relevant authority related to E-waste disposal.

Single, Double-Sided and Multi-Layer PCBs

During the printed circuit board design process, you have to know the differences between different PCB types, such as single PCB, double-sided PCBs, because it really impact the working efficiency on your finished PCBs. EPCB is here to give you some suggestions about how to choose a suitable PCB type for your application, so you can start in a right direction. Single sided boards are made from rigid laminate with copper on one side of varying thickness. Double-sided boards differ in that they have copper on both sides of the laminate. A multi-layer PCB has copper foil on the top and bottom and inner layer cores. Each type of PCB has its own unique advantages, so you’d better work with an EPCB expert to choose a suitable one.

Salvaging Parts

When you are working on a new project it can be beneficial and economical to find printed circuit boards and components from your old electronic products which can be reuse. This lets you test out your application in the early stages and work on your overall project design before ordering PCBs. Though reusing older parts will cut down on your costs, it may limit the performance of you new products to some extent.

Recycling your old PCBs and designing new advanced ones in their place will help you unlock the potential of your application as it continues in its development.

EPCB dedicates itself to producing the highest quality PCBs and products while minimizing any negative effects that manufacturing can have on the environment. Every piece of scrap PCB boards produced from EPCB’s manufacturing processes is taken directly to a certified refinery to ensure they are responsibly extracted and recycled.