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CatalogⅠ Fuse holder basics    1.1 What is a Fuse Holder?    1.2 Features of the Fuse Holder    1.3 Standards of the Fuse Holder    1.4 Thermal Considerations of Fuses and Fuse Holders    1.5 Application of Fuse Holder    1.6 Design Strategies of Fuses and Fuse HoldersⅡ Automotive Blade Fuse Holders    2.1 Sealed Mini Fuse HolderⅢ Fuse Blocks, Fuse Holders & Fuse CoversⅣ Fuse Holder, Fuse Carrier & Fuse ClipⅤ Inline Fuse & Inline Fuse Holder    5.1 What is an Inline Fuse?    5.2 What Does an Inline Fuse Look Like?    5.3 What Does an Inline Fuse Do?    5.4 Replacing an Inline Fuse    5.5 How to Install an Inline Fuse    5.6 How Does an Inline Fuse Work?    5.7 How to Install an Inline Fuse Holder    5.8 Fuses vs. Circuit BreakersⅥ LED Blow Fuse Indicators/LED Fuse Holders    6.1 How Does an LED Blown Fuse Indicator Work?    6.2 Glass Fuse Holders    6.3 AGC Fuse Holders    6.4 ATM/Mini Fuse Holders    6.5 Low Profile Fuse HoldersⅦ Quality Industrial Fuse Products at Low PricesIntroductionFuse holders and blocks are simple components that provide a critical function: mounting, enclosing, and safeguarding electrical fuses. Circuit protection is frequently included in electronic devices. In the event of a circuit overload, the principal duty is to protect both the equipment and the equipment operator. This safeguard is usually in the form of a circuit breaker or a fuse. A circuit breaker is an automated switch that stops the passage of electric current when it is rapidly overloaded or under extremely high stress. A fuse is a type of safety device that protects an electrical circuit against overcurrent. Imperial has everything you need, including open and enclosed alternatives. Choose from a variety of clip, block, socket, and plug-on cap styles in a variety of amperages. You'll have peace of mind knowing that your fuses are safely and continually protected in any commercial, industrial, or automobile application. The article will direct you to the necessary information and dispel any doubts you may have.Ⅰ Fuse holder basics1.1 What is a Fuse Holder?DIY Mount A Panel-Mount Fuse HolderA fuse holder, as the name implies, is a device that retains an electrical fuse. They are available in a variety of styles, each tailored to a certain fuse. A fuse holder's style and size are directly tied to the type and current rating of the fuse it is designed to retain. A blade fuse, for example, will not fit in a cartridge fuse holder. To help prevent electrical damage, many fuses and fuse holders incorporate specific features that prevent fuses of the correct style but incorrect current rating from being put in the holder. Furthermore, certain fuse holder models allow the fuse to be removed by hand, whereas others require the use of a specific tool.Electronic fuse holders are commonly classified into four types: Printed Circuit Board (PCB) Fuse Clips, Printed Circuit Board Fuse Holders, Panel Mount Fuse Holders, and In-Line Fuse Holders.PCB Fuse Clips – Most cost-effective, with the lowest purchase cost but the fewest features. They usually need to be isolated and insulated from the environment, yet they have a wide range of applications.PCB Fuse Holders – Most cost-effective, with the lowest purchase cost but the fewest features. They usually need to be isolated and insulated from the environment, yet they have a wide range of applications.Panel Mount Fuse Holders – They are normally wire-in, wire-out/line, and load, and when installed appropriately, they can protect people from electrical risks when mounted through an enclosure or on a back plane of an enclosure.In-Line Fuse Holders – These wire-in, wire-out/line and load fuse holders are essentially self-contained wire harnesses that offer a wide range of application versatility. Depending on the designer's objective and where they are situated, they can allow for both easy fuse replacement and make fuses more difficult to access.1.2 Features of the Fuse HolderWaterproofing, vibration resistance, and a blow fuse warning are all common features of fuse holders.1.3 Standards of the Fuse HolderUsers of UL/CSA-compliant fuse holders are accustomed to a fuse carrier with a knurled cap that allows them to reach and change a fuse without the need for tools. However, some international equipment standards limit the degree of user accessibility to a fuse holder to reduce the risk of electrical shock to a non-technical user. The limited access fuse holder is built to necessitate the use of a tool (usually a screwdriver). It also includes extra insulation and insulating barriers to prevent the presence of living conducting services during fuse change procedures.Approvals and ratings for fuse holders include UL, CSA, BSI, VED, IEC (UMF), SEMKO, and Dentori.The UL Listing guarantees that a fuse has been manufactured in full compliance with the UL 248-14 standard. UL recognition, c-UL Listing, c-UL Recognition, c-UL-us Listing and c-UL-us Recognition does not imply full compliance with UL-248-14. CSA Canadian approval that guarantees the a fuse or fuse holder has been manufactured in full compliance with the CSA C22.2 No. 248.14 or CSA C22.2 No. 39 standard, respectively.The BSI British approval guarantees that a fuse has been manufactured in full compliance with the appropriate section of IEC 60127 (BS 4265) standard.The VDE German clearance ensures that a fuse or fuse holder was manufactured in complete compliance with the relevant provision of the IEC 60127 standard.IEC approval pertains to Universal Modular Fuses (UMF) that have been verified to be compliant with IEC 60127-4.SEMKO Swedish clearance ensures that a fuse or fuse holder was manufactured in complete compliance with the relevant portion of the IEC 60127 standard.1.4 Thermal Considerations of Fuses and Fuse HoldersWhen designing a piece of equipment that will use fuses and fuse holders, the design engineer(s) must consider thermal influences such as ambient temperature and heat rise to the temperature specifications of the fuses and fuse holders to select the best components for the applications and possibly expand the design to alleviate problems with heat build-up. It is critical to choose the best fuse and fuse holder combo. Among other things, the engineer must ensure that the maximum permissible power acceptances and temperatures specified by the fuse holder's manufacturer are adhered to.Factors to Consider Include:The effect of power dissipation in fuse holderconnectionsThe chosen fuse's rated power dissipationAcceptable power acceptance, temperature ratings, and fuse holder operating currentTemperatures of the ambient air both inside and outside the apparatusAltering the electrical loadLong-term operation with a load greater than 0.7InHeat impacts of nearby componentsHeat dissipation/cooling, as well as ventilation, are included in the equipment.Connecting wire length and cross-sectionThe fuse holder's mounting orientationMost fuse and fuse holder manufacturers provide thorough information on the aforementioned variables as well as great guide material for making the appropriate selections.After considering the aforementioned factors, a decision on an acceptable fuse and fuse holder combination can be made. It is then recommended that testing be performed on the chosen devices under the worst-case operating conditions to validate the selection. If problems emerge that indicate excessive heat buildup, a new option or design alterations may be required to ease the situation.1.5 Application of Fuse HolderGlass and ceramic cartridge fuses, as well as automobile blade fuses, are held in place by fuse holders. We offer panel mount fuse posts, multi-fuse blocks, and inline holders.1.6 Design Strategies of Fuses and Fuse HoldersThe following are some things to think about while designing with fuses and fuse holders in mind. Due to the variety of conditions, a broad selection of fuse sizes and types are available to handle circuit protection, as well as different forms of fuse holders for putting the fuse into a circuit. To guarantee a satisfactory pairing, design considerations must include both the fuse and the fuse holder.These include:What size fuses would be most appropriate?What are the load ratings for the application?Is there a huge in-rush on the equipment when it first starts up?How long can the device withstand an overload?Is the overload large enough to physically destroy the fuse?Thermal factors to consider:The fuse link's power dissipationThe fuse holder's ratingsTemperatures inside and outside of the apparatusChanges in electrical loadLong durations of operationVentilation, cooling, and heat dissipation are all important.Wire lengths and diametersⅡ Automotive Blade Fuse HoldersFor Mini, Low Profile, Standard and Maxi Blade FusesPCB Mountable for Reliable Connection and SecurityUL Recognition for PCB Auto Fuse Holders Mini sizes are compatible with Littelfuse ATO 297 series and Bussman ATM series automotive blade fuses and come pre-assembled for quick mounting and soldering to the PCB. Suitable for applications requiring up to 20 AmperesLittelfuse 0891 series and Bussman Low Profile ATM series automotive blade fuses are compatible with LP Mini sizes.Suitable for applications requiring up to 20 AmperesStandard sizes are compatible with automotive blade fuses from the Littelfuse ATO 257 series and the Bussman ATC series.Suitable for applications requiring up to 30 AmperesLittelfuse MAXI series and Bussman MAX series automotive blade fuses are compatible with Maxi sizes. Suitable for applications requiring up to 40 AmperesIn Thru-Hole Mount Cat Nos. 3557-2 and 3587, a 2 in 1 fuse holder is also available to accommodate both Standard and Low Profile Minitype Automotive Blade Fuses.2.1 Sealed Mini Fuse HolderApplications:Circuit and component safeguardsElectric motorsCompressorsLightingPumps powered by electricityEnvironmentally sealed circuit protection is required for high vibration applications in truck and bus, agriculture, construction, marine, and special vehicles industries.Key Benefits:Add a sealed fuse quickly and easily anywhere.Several mounting options are provided, with mounting clips readily available.Accepts tiny fuses that are industry standard.For proven dependability, a high-performance AMP MCP terminal system is used.Ⅲ Fuse Blocks, Fuse Holders & Fuse CoversFuse blocks, holders, and covers keep fuses secure and safe when they are attached to an electrical circuit. They're usually made to accommodate specified fuse classes, types, and sizes. Fuse blocks and holders provide an electrical connection point for installing fuses and retaining them in place to maintain circuit contact. Fuse block covers are attached to each fuse in a block to avoid accidental contact with live clips and terminals.A fuse holder, as opposed to a fuse block, only carries one fuse to complete a single circuit. A fuse holder is especially beneficial in systems with a separate power source from the fuse block or that require a fusible link closer to the electrical system it serves. Whether you've lost power to one of your systems and the fuse isn't in the fuse box, verify if it has a separate fuse holder. If the fuse at the fuse holder is not blown, the fuse holder may need to be changed. If your automobile, truck, or SUV requires a new fuse holder,Fuse block insulators can be made of phenolic or molded polycarbonate. All blocks fulfill the UL and CSA criteria for rated voltage clearance and creepage in common industrial control devices. All blocks have passed high current withstand short circuit tests and can be utilized up to the interrupting rating of the fuse class used. Ⅳ Fuse Holder, Fuse Carrier & Fuse ClipThe fuse is held in place by a fuse holder, which is attached to the equipment. Fuse holders can accommodate both North American and international fuses. This is determined by the fuse carrier utilized. Panel-mount fuse holders are available from Interpower.International "touch-proof" fuse holders are a well-liked option. This fuse holder is offered in three sizes: low-profile, high-profile, and low-profile/snap-in. Each of these comes in a variety of terminal designs, including fast disconnect, solder/quick disconnect, and angled variants of both. Interpower fuse holders take both North American and international fuse carriers and can be utilized in almost every market across the world. These fuse holders have the added feature of being touch-proof, which increases the end user's safety—the blown fuse can only be retrieved from the outside of the equipment with a tool and cannot touch any of the contact surfaces before the fuse carrier and fuse are removed.On fuse holders, approvals are available.A fuse carrier is the fuse holder's "cap." It transports the fuse into the holder and secures it in place. One advantage of combining a fuse carrier with a fuse holder is that they are touch proof.¼ x 1-¼ For inch FuseFor 5 x 20mm FuseP/N: 80920200P/N: 80920210Two Examples of a Fuse Carrier Fuse ClipA fuse clip is used to secure internal fuses on PC boards. One fuse necessitates the use of two clips.Fuse clips, which have many of the same characteristics as fuse blocks, are an alternative to fuse blocks.Fuse clips can be soldered to a printed circuit board or screwed into a panel. Fuse clips are an intriguing alternative to PC-Board mount fuse holders since they are reasonably affordable. Interpower fuse clips are only available in one size. They are PC-board mounted and can only be accessed from within the equipment. It has a "stop" on it to aid in the positioning of the fuse when it is placed.Fuse clips do not have any approvals unless they are part of a final product. They are an appealing alternative to post-style and PC-board mount fuse holders due to their low cost. When using fuse clips, the designer must keep in mind that each end is a different piece. For each fuse that is used, two clips must be ordered.Ⅴ Inline Fuse & Inline Fuse Holder5.1 What is an Inline Fuse?Fuses are electrical and electronic components that serve as safety devices. An in-line fuse differs from other types of fuses in that it is contained within a cable rather than a ceramic or glass cartridge. If you're looking for an in-line fuse, discover more about its purposes and how it works, then contact Gateway Cable Company for more information about our in-line fuse assemblies.5.2 What Does an Inline Fuse Look Like?In-line fuses are often made up of two cables connected by a fuse and fuse holder or fuse box. One cable connects to the positive power supply, while the other connects to the device or equipment being powered. The fuse used to separate the two cables protects the circuit of whatever is being provided. The householder, often known as a fuse box, protects the fuse and is frequently watertight.5.3 What Does an Inline Fuse Do?What Does an Inline Fuse Do?An in-line fuse, like other types of fuses, serves to protect the circuit of a piece of electrical or electronic equipment. When an electrical device is unexpectedly overcharged with current, the filament within the fuse melts and the circuit is broken. In-line fuses differ from other types of fuses in appearance but function the same way. Automotive is one of the most prevalent applications for in-line fuses. Starter motors often consume the most current of any component within a car. In-line fuses, which are meant to break the circuit if it becomes overloaded, are frequently employed to protect the alternator.5.4 Replacing an Inline FuseTo replace an in-line fuse, detach the two connecting halves and split the fuse holder or fuse box into two portions. After separating the two parts, replace the old fuse with a new one.5.5 How to Install an Inline FuseWhile there are many other types of fuses available to assist you in achieving or maintaining the power you require, an inline fuse can be a wonderful component to ensure an even distribution of electricity for your circuit. So, if you need to add a fuse holder to your car or some of your home's lighting, you'll need to know how to install an inline fuse line correctly. Fortunately, the professionals at Gateway Cable Company are here to explain all you need to know to get the job done!5.6 How Does an Inline Fuse Work?If you've never used an inline fuse holder before, you're probably thinking, "How does an inline fuse holder work?" An inline fuse, like other fuses, is used to manage the current of electricity running through your circuit and is intended to protect extra electrical components in your car. An inline fuse will split up the current if your circuit becomes overcharged, preventing any potential damage.5.7 How to Install an Inline Fuse HolderWhen it comes to installing inline fuses, you'll need a few tools to get the job done correctly. A pair of wire cutting and stripping pliers, crimping pliers, butt-splice crimp connectors, and, of course, the right amperage-rated fuse holder are all required. Once you have all of these supplies, carefully follow these procedures to install an inline fuse holder:step 1Unplug your gadget from the power source.step 2Using the wire cutting pliers, cut the positive wire closest to your circuit.step 3Using the wire-stripping pliers, cut 1/4-inch from each end of the split wires and the fuse holder. To avoid damaging the internal components of the inline fuse, keep the wires tight during stripping.step 4Spiralize your circuit wires to make the stripped ends firmer and easier to attach.step 5Using the crimping pliers, insert the twisted circuit wire into the butt-splice crimp connection.step 6Using the crimping pliers, insert either end of the fuse holder wires into the other end of the butt-splice connector. Make certain that both ends are securely fastened.step 7While clamping the wire, twist the leading device wire and put it into a butt-splice connection.step 8Twist the fuse holder's other wire end and place it into the butt splice attached to the wire heading to the device, then crimp down.step 9Insert the appropriate amperage fuse into the fuse holder and join the halves by pressing down and securing them in place.step 10Repair your device's power supply. 5.8 Fuses vs. Circuit BreakersFuses and circuit breakers both serve the same purpose: to prevent over-current situations that could be hazardous to one's safety. They are not the same, despite the fact that they are frequently misunderstood. As previously stated, fuses are replaceable; in over-current situations, the filament inside a fuse's cartridge will melt and shut down the circuit. Circuit breakers are a sort of resettable fuse in several ways. When the load on a circuit exceeds the load on a breaker, the breaker employs a bimetal strip or solenoid to trip the switch and protect the circuit. Breakers that have been tripped can be readily reset and do not need to be replaced.Ⅵ LED Blow Fuse Indicators/LED Fuse Holders6.1 How Does an LED Blown Fuse Indicator Work?An LED blown fuse indicator is used to quickly and simply determine whether or not a fuse needs to be replaced without removing it from the fuse holder. The indication is made up of two contact wires, one for the line and one for the load, as well as a high value resistor and an LED indicator. The wires are connected to the fuse's respective ends. If the fuse is good and thus conducting electricity, the majority of the current flows through it; if the fuse is bad, current from the circuit flows through the indicator, illuminating the LED light. In layman's terms, a lit bulb means a blown fuse.6.2 Glass Fuse HoldersWater-resistant inline glass fuse holder: for AGC and SFE glass fuses, certified for a maximum of 30 amps; yellow neoprene for high visibilityUniversal inline glass fuse holder: for AGC and SFE type fuses, rated for a maximum of 30 amps; Snap-Lock design ensures a strong positive union of fuse holder housing; ROHS complianceHeavy-duty inline glass fuse holder: rated for a maximum of 60 amps; 6" loop length, 8-gauge wire; ROHScompliant6.3 AGC Fuse HoldersLight duty ATO/ATC MidBlade fuse holder: rated for 15 amps maximum; 12" loop length, 16-gauge wireInline ATO/ATC heavy duty fuse holder: 30 Amp inline blade fuse holder; 12" loop length, 12-gauge wire; 30 Ampfuse includedInline ATO/ATC stackable fuse holder: 30 amp inline blade fuse holder with weather-resistant cover; 5.5" loop length, 12-gauge wire; 30 amp fuse includedSelf-stripping ATO/ATC fuse holder: rated for 40 amps maximum; no need to strip wire—enter each wire and crimp the holder closed, then insert fuse to complete the circuit.Inline ATO/ATC fuse holder with cover rated for 30 amps maximum; accommodates 12-gauge and smaller wire; screws tighten wire; fuse and two weather-tight covers includedWaterproofing ATO/ATC fuse holder: rated for 30 amps maximum; two 4" 12-gauge lead wires; snap-on cover with mounting hole included; ROHS compliant.ATO/ATC fuse holder rated for 20 amps maximum; 12" loop length, 14-gauge wireMedium duty inline AGC glass fuse holder: accepts ACG and SFE fuses, rated for a maximum of 20 amps; 14-gauge wire, 8" loop; ROHS compliant6.4 ATM/Mini Fuse HoldersInline ATM mini fuse holder with cap ring terminals: includes a 15 Amp mini fuse with 5/16" diameter ring terminals attached to 3-1/4" wires; 12-gauge wire, 10-5/8" loop.Stackable micro fuse holder for ATMs in line:30 amp micro blade fuse holder with 12 gauge wire and 5-1/2" wire leads; weather resistant lid; fuse includedMini fuse holder for ATMs inline with a cover:20-amp fuse holder with 16-gauge wire and two 6-inch wire leads; water resistant lid; RoHS compliantATM small fuse holder: weatherproof, rated for 30 amps maximum; two 5" wire leads, 12-gauge wire6.5 Low Profile Fuse HoldersLow profile inline fuse holder with splash-proof cover: rated for 20 amps maximum; 5" wire leads, 14-gauge wire; ROHS compliantLow profile inline fuse holder with weather-resistant cover: rated for 10 amps maximum; 6" wire leads, 18-gauge wireⅦ Quality Industrial Fuse Products at Low PricesFuse holders and fuse blocks are available from Automation Direct in a variety of styles.Fuse Holders & Accessories with a Small Dimension of 1/4 inch5mm Fuse Holders & Accessories in Small DimensionsFuse Holders & Accessories for Class CC & Midget (30A)Fuse Blocks & Accessories for Modular Class CC & Midget (30A)Fuse Holders & Accessories for Modular Class J (30 - 60A)Fuse Blocks and Accessories for Modular Class J (30-600A)Fuse Blocks & Accessories for Modular Class J Power Distribution (100-400A)Fuse Holders, Fuse Blocks, and Accessories (30-600A) Class RK1 and RK5 Fuse Blocks and Accessories (30-600A)Fuse Blocks and Accessories for the Modular Class RK1 and RK5 (30-600A)

Ⅰ IntroductionLithium batteries are a type of battery that uses lithium metal or lithium alloy as the cathode material and use a non-aqueous electrolyte solution. Lithium battery is an ambiguous term. In 1912, lithium metal batteries were first proposed and studied by Gilbert N. Lewis. In the 1970s, M. S. Whittingham proposed and began researching lithium-ion batteries. Due to the very active chemical properties of lithium metal, the processing, storage, and use of lithium metal require very high environmental requirements. With the development of science and technology, lithium batteries (broadly speaking) have now become mainstream. CatalogⅠ IntroductionⅡ HistoryⅢ Li & Li-ion Battery Features3.1 Advantages3.2 DisadvantagesⅣ Lithium Battery VS Lithium Ion Battery4.1 Lithium Batteries4.2 Li-ion BatteryⅤ ApplicationⅥ Battery Security6.1 Battery Storage6.2 Charging Rules6.3 Battery ExplosionⅦ Development ProspectsⅧ One Question Related to lithium metal & lithium ion Battery and Going Further8.1 Question8.2 AnswerⅡ HistoryIn the 1970s, M.S. Whittingham used titanium sulfide as the positive electrode material and metallic lithium as the negative electrode material to make the first lithium battery.In 1980, J. Goodenough discovered that lithium cobaltate could be used as a cathode material for lithium-ion batteries.In 1982, R.R.Agarwal and J.R.Selman of the Illinois Institute of Technology discovered that lithium ions can be embedded into the graphite, which is fast and reversible. At that time, lithium batteries made of metal lithium have attracted much attention because of their safety issues. Therefore, people tried to embed lithium ions to graphite to make rechargeable batteries. Finally, first available lithium-ion graphite electrode was successfully trial-produced by Bell Labs.In 1983, M. Thackeray, J. Goodenough, and others found that manganese spinel is an excellent cathode material, which has good properties of low cost, stability, and excellent electrical and lithium conduction. Its decomposition temperature is high, and its oxidizing property is far lower than that of lithium cobaltate. Even if having a short circuit or overcharge, combustion and explosion can be avoided as far as possible.In 1989, A. Manthiram and J. Goodenough discovered that a positive electrode using a polymeric anion would generate a higher voltage.In 1991 Sony released the first commercial Li-ion battery. Subsequently, lithium-ion batteries revolutionized the development of consumer electronics. For example, the weight and volume of portable electronic devices such as mobile phones, notebooks, and calculators has greatly reduced.In 1996, Padhi and Goodenough discovered that phosphates with an olivine structure, such as lithium iron phosphate (LiFePO4), are more superior than traditional cathode materials, and  become the mainstream cathode materials gradually.Lithium batteries were first used in pacemakers. Lithium batteries have the advantages of low self-discharge rate and gentle discharge voltage, so that the pacemaker implanted in the human body can operate for a long time without recharging. Lithium batteries generally have a nominal voltage higher than 3.0V, making them more suitable as integrated circuit power supplies.To develop a new better lithium battery, various materials have been researched and tested. Ⅲ Li & Li-ion Battery Features3.1 Advantages1) High energy density. With high storage power density, it has reached 460-600Wh / kg, which is about 6-7 times that of lead-acid batteries. It is one of the major advantages of lithium ion battery technology. For example, high energy-dense 18650 cells can deliver over 3,000mAh and the costs have dropped further today.2) Long cycle life, the service life can reach more than 6 years. For example, the battery 1C (100% DOD) with lithium ferrous phosphate as the positive electrode is charged and discharged about 10,000 times.3) High rated voltage, a single battery working voltage is 3.7V or 3.2V, which is approximately equal to the series voltage of 3 Ni-Cad or Ni-MH rechargeable batteries, in addition, it is convenient to form a battery power pack. What’s more, lithium batteries can use a new type of voltage regulation technology to adjust the voltage to 3.0V to suit the use of small appliances.4) High power resistance capacity. For example, phosphate lithium-ion battery for electric vehicles can reach 15-30C charge and discharge capacity, which is convenient for high-intensity startup acceleration.5) Low self-discharge rate. It is one of the most outstanding performances of the battery, which can generally be less than 1% per month, and it is much lower than that of other rechargeable cells such as Ni-Cad and NiMH batteries.6) Light weight, about 1 / 6 to 1 / 5 of lead acid products under the same volume.7) Good performance at high and low temperature. For example, the battery can be used in the environment of -20 ℃ ~ 60 ℃, after processing, it can be used in the environment of -45 ℃.8) Less harm to environment. Regardless of production, use and scrap, it does not contain or produce any toxic and harmful heavy metal substances, such as lead, mercury, cadmium.9) There are several types available. It means that the right technology can be used for the special application required. 3.2 Disadvantages1) Lithium primary batteries have poor safety and risk of explosion.2) Li-ion batteries (lithium cobaltate) cannot be discharged at high currents.3) Li-ion batteries need protecting circuit to prevent the battery from being overcharged and over discharged.4) Li-ion batteries will only last two or three years from the date of manufacture whether you use them or not.5) High production requirements and costs.6) Limited use conditions, because they are extremely sensitive to temperature.7) As for air transportation/travel, many airlines limit the number of lithium ion batteries they take.Ⅳ Lithium Battery VS Lithium Ion Battery4.1 Lithium Batteries4.1.1 ChemistriesLithium batteries are primary batteries that have metallic lithium as an anode, and metallic lithium or other alloy metals used as cathode, regarded PP or PE film as the the separator.Note: Discharge reaction: Li+MnO2=LiMnO2They have low self-discharge rate, annual self-discharge can be ≤1%. The service life of fully sealed (metal welded, lazer seal) batteries up to 10 years, and semi-sealed batteries are generally 5 years.Lithium metal is used as the negative electrode, and the positive electrode and the electrolyte are thionyl chloride (sulfoxide). Cylindrical batteries have electricity after assembly. The voltage is 3.6V, which is one of the most stable types of batteries. It is suitable for use on electronic instruments and equipment that cannot be maintained frequently, providing subtle current. 4.1.2 Battery StructureLithium batteries usually come in two shapes: cylindrical and square. The inside of the battery is a spiral winding structure, and a very fine and highly permeable polyethylene film separator is used to separate the positive and negative electrodes. The positive electrode contains a current collector composed of lithium cobaltate (or nickel-cobalt lithium manganate, lithium manganate, lithium ferrous phosphate, etc.) and the aluminum foil. The negative electrode consists of a current collector composed of graphitized carbon material and the copper foil. The battery is filled with an organic electrolyte solution. It is also equipped with a safety valve and a PTC element (partially cylindrical) to protect the battery from damage during abnormal conditions and output short circuits. 4.1.3 Battery Material AnodeThere are many choices of anode materials, for example, LiFePO4 is mostly used as mainstream products.  Chemistry ReactionThe lithium ion is embedded when discharge, and de-embedded in the charge.On Charge：LiFePO4 → Li1-xFePO4 + xLi+ + xe-On Discharge：Li1-xFePO4 + xLi+ + xe- → LiFePO4 CathodeGraphite is commonly used, and new research has found that titanate may be a better material. Chemistry ReactionThe lithium ion is de-embedded when discharge, and embedded in the charge.On Charge：xLi+ + xe- + 6C → LixC6On Discharge：LixC6→ xLi+ + xe- + 6C Conductive CoatingThe conductive coating is also called pre-coating. In industry, it usually refers to a layer of conductive coating applied to the surface of the positive electrode current collector-aluminum foil. The earliest experiments on aluminum foil in batteries can be traced back to the 1970s. With the development of new energy industry, especially the development of LiFePO4 batteries, it has become a hot new technology in the industry.The conductive coating can effectively improve the adhesion of the pole pieces in the lithium battery, reduce the amount of binder used, and also significantly improve the battery's electrical performance:1) Contact resistance decreases 40%2) Adhesive reduces 50%3) Battery voltage increases 20%at the same magnification.Material and current collector adhesion increases 30%, and no delamination after long-term cycling.In addition, carbon coated aluminum foil is another coating which made of conductive carbon-based composite paste and high-purity electronic aluminum foil by transfer coating process. 4.1.4 Shell CharacteristicsTo improve safety and voltage, scientists have invented materials such as graphite and lithium cobaltate to store lithium atoms. The molecular structure of these materials forms nano-scale small storage lattices that can be used to storage. In this way, even if the battery case is broken and oxygen enters, the oxygen molecules will be too large to enter these small storage cells, so that lithium atoms will not react with the oxygen to avoid explosion.  4.2 Li-ion Battery4.2.1 TerminologyLithium-ion battery is a type of batteries with non-aqueous electrolyte that uses lithium alloy metal oxides as anode material, graphite as cathode material.Li-ion batteries currently include liquid lithium-ion batteries (LIB) and polymer lithium-ion batteries (PLB). Among them, the liquid lithium ion battery refers to a secondary battery whose Li + is compound. The positive electrode uses lithium cobaltate and lithium manganate, and the negative electrode uses a lithium-carbon interlayer compound. Li-ion batteries have advantages of high operating voltage, small size, light weight, high energy, no memory effect, no pollution, small self-discharge, and long cycle life. Note:Reaction on anode: LiCoO2==Li(1-x)CoO2+XLi++Xe-(electron)Reaction on cathode: 6C+XLi++Xe- = LixC6Total reaction: LiCoO2+6C = Li(1-x)CoO2+LixC6Its practicality has greatly reduced the weight and volume of portable electronic devices such as mobile phones and notebook computers, and the using time is greatly extended. Because lithium-ion batteries do not contain heavy metal cadmium, compared with nickel-cadmium batteries, the environmental pollution is greatly reduced. 4.2.2 Li-ion Battery Characteristics High energy densityThe weight of a Li-ion battery is half that of a nickel-cadmium or nickel-hydrogen battery of the same capacity, and the volume is 20-30% of a nickel-cadmium battery and 35-50% of a nickel-hydrogen battery. High voltageThe operating voltage of a lithium-ion battery cell is 3.7V (average value), which is equivalent to three nickel-cadmium or nickel-metal hydride batteries connected in series. Small pollutionLi-ion batteries do not contain harmful metal substances such as cadmium, lead, and mercury. No lithium metalLi-ion batteries do not contain metallic lithium, so they are not subject to the ban imposed by airlines of carrying lithium batteries in passenger aircraft. Long cycle lifeUnder normal conditions, the charge-discharge cycle of a lithium-ion battery can exceed 500 times, and a iron phosphate battery can reach 2000 times. No memory effectThe memory effect refers to the phenomenon that the capacity of the battery decreases during the charge and discharge cycle of the nickel-cadmium battery. Lithium-ion batteries do not have this effect. Quick chargeUsing a constant current & voltage charger with a rated voltage of 4.2V, the lithium-ion battery can be fully charged in 1.5 ~ 2.5 hours; and the newly developed lithium iron phosphate battery can be fully charged in 35 minutes. 4.2.3 Matters of UseKeeping lithium-ion batteries regularly charged and discharged can extend battery life. Lithium-ion battery power is maintained at 10% ~ 90% is better for the battery. This means that you don't need to reach 100% when charging batteries for digital products such as mobile phones and laptops. Under normal circumstances, 50% of the power is best for lithium-ion battery storage.When digital products equipped with lithium-ion batteries are exposed to sunlight or stored in hot cars, it is best to turn these products off because lithium-ion batteries will age faster if the operating temperature exceeds 60℃. 4.2.4 Li-ion Battery SelectionLi-ion batteries are divided into liquid lithium-ion batteries and polymer lithium-ion batteries. The electrolyte of a lithium-ion battery is fluid, so it is more unstable than a lithium polymer battery, and it may explode if it is hit by an external force or if a non-compliant charger is used. And now that the popularization of portable electronic products such as smart phones, e-books, tablets, and laptops uses batteries as a power source, battery hidden troubles will break out at any time. To prevent these, we must pay attention to the following:1) The capacity is clearly marked. Batteries without a clearly marked capacity (such as 1000mAh) are likely to be inferior or recycled.2) Standby time. It is the continuous use time from the time the battery is loaded to the next charge.3) Safety protection circuit board. Without it, the lithium battery is at risk of deformation, leakage, and explosion.Lithium Ion Vs Lithium Polymer BatteriesⅤ ApplicationWith the development of microelectronic technology, more and more miniaturized devices have been put forward, which places high requirements on power sources. Lithium batteries have subsequently entered a large-scale practical stage.The earliest application was lithium sub primary battery, used in pacemakers. Due to the low self-discharge rate and gentle the discharge voltage, this makes it possible to implant the pacemaker into the human body for long-term use.Lithium manganese batteries generally have a nominal voltage higher than 3.0V, which is more suitable for integrated circuit power supplies and is widely used in computers, calculators, and watches.Li-ion batteries are widely used in mobile phones, notebook computers, power tools, electric vehicles, street light backup power supplies, navigation lights, and small household appliances, which can be said to be the most popular type.Ⅵ Battery Security6.1 Battery Storage6.1.1 Lithium BatteryPrimary lithium battery can be discharged continuously or intermittently. Once the power is exhausted, it can no longer be used, and it is widely used in electronic products with low power consumption such as cameras. It has a low self-discharge rate and can be stored for up to 3 years. In addition, it is good to store lithium primary batteries in low temperature to get better storage.Note: Lithium primary batteries are different from lithium ion batteries, the former cannot be charged. 6.1.2 Li-ion BatteryAlso called secondary lithium battery. It can be stored for more than half a year at 20°C. This is due to its low self-discharge rate and most of its capacity can be recovered.The self-discharge phenomenon e4xists in lithium batteries. If the battery is stored below 3.6V for a long time, it will cause the battery to over-discharge and damage the internal structure of the battery, reducing the battery service life. Therefore, long-term storage of lithium batteries should be recharged every 3 to 6 months, that is, keeping the battery voltage at 3.8 ~ 3.9V, and it is appropriate to maintain the discharge depth at 40% ~ 60%. The battery should be stored in a dry environment at 4 ℃ ~ 35 ℃ or in a moisture-proof packaging. In addition, Keep away from heat sources and sunlight.Storage requirements: In the environment with a temperature of 20 ± 5℃ and a humidity of no more than 50%, the air and water vapor must be prevented from contacting the aluminum foil during transportation. 6.2 Charging Rules Charging voltageGenerally, the battery voltage of a mobile phone is 3.7V, but the voltage of a general charger is 5V, but it will not affect the use. Shallow charge and dischargeThis is more beneficial for lithium batteries. Only when the power module of the product is calibrated for lithium batteries, it is necessary to deepen and deep charge. Therefore, lithium-ion-powered products do not have to be constrained by the process. Overcharge and overdischargeThe rated voltage of a lithium-ion battery is generally 3.7V. Depending on different materials, the positive electrode of lithium iron phosphate is 3.2V. The international standard for termination charge voltage when fully charged is 4.2V, and iron phosphate is 3.6V. Overdischarge or self-discharge reaction at low voltage will cause decomposition and destruction of lithium active material, and may not be recovered. And any kind of overcharging of lithium-ion battery will cause severe damage to the battery performance and even cause explosion. Therefore, the lithium-ion battery must avoid overcharging during the charging process.6.3 Battery Explosion6.3.1 Explosions ExpressThe type of battery cell explosion can be summarized into three types: external short circuit, internal short circuit, and overcharge. Here, the “external” refers to the outside of the battery cell and includes short circuits caused by poor internal insulation design of the battery pack. When a short circuit occurs outside the battery cell and the electronic component fails to cut off the circuit loop, high heat will be generated inside the battery cell, causing some of the electrolyte to vaporize, which will expand the battery case.When the internal temperature of the battery reaches 135 degrees Celsius, a good quality separator paper will close the pores, the electrochemical reaction will be terminated almost, the current will drop suddenly, and the temperature will decrease slowly, avoiding the explosion. However, if the pore closing rate is too poor, or the separator paper with poor quality, the battery temperature will continue to increase, causing more electrolyte vaporize, and finally the battery case will be broken, even be exploded.The internal short circuit is mainly caused by piercing diaphragm by the burrs of copper foil and aluminum foil piercing the diaphragm, or dendritic crystals of lithium atoms.These tiny needle-like metals can cause micro-short circuits. The copper and aluminum foil burrs are caused during the production process, and the observed phenomenon is that the battery leaks too quickly, and most of them can be detected by the cell plant or assembly plant. Moreover, because the burr is small, it is sometimes blown out, which makes the battery return to normal. Therefore, this kind of explosion is less happened. Therefore, the explosion caused by the internal short circuit is mainly caused by overcharge.After overcharging, needle-shaped lithium metal crystals are everywhere on the pole pieces, piercing points are everywhere to make micro short circuits. Therefore, the temperature of the battery will gradually increase, and finally the electrolyte is vaporized at high temperature. In this case, whether the temperature is too high to damage electrode materials and the battery housing burns and explodes, both situations will cause an explosion.Based on the above types of explosions, we can focus on batteries protection in three aspects: overcharge, external short circuits, and improvement of battery safety.When designing a battery system, two electronic protections must be provided for overcharge, overdischarge, and overcurrent. Final protection method, the safety level of batteries, which can be roughly differentiated according to the ability to withstand short circuit and overcharge. In addition, before the battery explodes, if lithium atoms accumulate on the surface of the battery, the explosion power will be greater. Comparing the performance of aluminum shell cells with steel shell cells, aluminum shells have high safety advantages. Moreover, consumers use inferior chargers. Thus the ability of cells to resist overcharge is more important than the ability to withstand external short circuits. 6.3.2 Explosion Causes1) Large internal polarization2) The pole piece absorbs water and reacts with the electrolyte.3) The quality and performance of the electrolyte.4) The amount of injection does not meet the process requirements.5) Poor sealing performance during laser welding in assembly process.6) Manufacturing dust is easy to cause micro short circuit.7) The positive and negative plates are thicker according to technological requirements, and it is difficult to insert the case.8) Sealing problem of liquid injection, for example, poor sealing of steel ball causes air drum.9) The shell is too thick, and the deformation of the shell will affect the thickness.10) High external ambient temperature. 6.3.3 Protection MeasuresTo avoid over-discharging or over-charging due to improper use, a triple protection mechanism is provided in the single-cell lithium-ion battery. The first is the use of switching elements. When the temperature in the battery rises, its resistance value rises, if the temperature is too high, the power supply will automatically stop. The second is to choose an appropriate separator material. When the temperature rises to a certain value, micron-sized micropores on the separator will automatically dissolve, so that lithium ions cannot pass through, and the internal reaction of the battery stops. The third is to set a safety valve (that is, the vent hole on the top of the battery). When the internal pressure of the battery rises to a certain value, the safety valve will automatically open to ensure the safety of battery.Sometimes, although the battery itself has safety control measures, due to some reasons, for example, security control fails, or the lack of a safety valve, or the gas is too slowly to release through the safety valve, therefore, the internal pressure of the battery will rise sharply and cause an explosion.In general, the total energy stored in a lithium-ion battery is inversely proportional to its safety. As the battery capacity increases, the battery volume also increases, its heat dissipation performance becomes poor, and the possibility of accidents will increase significantly. For Li-ion batteries for mobile phones, the basic requirement is that the probability of a safety accident is less than one in a million. For large-capacity lithium-ion batteries, especially electric vehicles, the use of forced heat dissipation is particularly important.Choose a safer electrode material, for example lithium manganate material, to ensure that the molecular structure is fully charged, the lithium ions of the positive electrode have been completely embedded in the carbon pores of the negative electrode to avoid the generation of dendrites is fundamentally. At the same time, the stable structure of lithium manganate makes its oxidation performance much lower than that of lithium cobaltate, and the decomposition temperature exceeds 100 °C of lithium cobaltate. The danger of burning and explosion caused by the precipitation of metallic lithium is avoided when having short circuit or overcharge.After the lithium battery cell is overcharged to a voltage higher than 4.2V, side effects will begin to occur. The higher the overcharge voltage, the higher the danger. Because the number of lithium atoms remaining in the positive electrode material is less than half, at this time, the storage cell collapses, causing the battery capacity to permanently decrease. If you continue to charge, since the storage cell of the negative electrode is already filled with lithium atoms, subsequent lithium metal will accumulate on the surface of the negative electrode material. These lithium atoms will grow dendritic crystals from the surface of the negative electrode toward the lithium ions. These lithium metal crystals will pass through the separator paper, making the positive and negative electrodes short-circuit. Sometimes the battery explodes before a short circuit occurs.When at a  overcharge process, materials such as the electrolyte will vaporize, which will cause the battery case or pressure valve to swell and rupture, allowing oxygen to enter and react with the lithium atoms accumulated on the negative electrode surface.Therefore, when charging a lithium battery, the upper limit of the voltage must be set to guarantee the battery life, capacity, and safety. The optimal charging voltage limit is 4.2V. There is also a lower voltage limit when the lithium battery is discharged. When the cell voltage is lower than 2.4V, some materials will start to be destroyed. In addition, when the lithium battery is discharged from 3.0V to 2.4V, the released energy accounts for only about 3% of the battery capacity. Therefore, 3.0V is an ideal discharge cutoff voltage. When charging and discharging, the limitation of current is also necessary. If the current is too large, lithium ions have no time to enter the storage cell, and will collect on the surface of the material, which will affect the battery performance.After these lithium ions have obtained electrons, lithium atom crystals will be generated on the surface of the material, which will cause danger, like overcharge. Therefore, the protection of lithium-ion batteries must include: the upper limit of the charging voltage, the lower limit of the discharge voltage, and the upper limit of the current. In general, except the lithium battery cell, there is a protective plate in the lithium battery pack.Ⅶ Development ProspectsTo develop more excellent batteries, various materials have been studied. For example, lithium sulfur dioxide batteries and lithium thionyl chloride batteries are very characteristic. Their positive electrode active materials are solvents for the electrolyte. This structure made only in non-aqueous electrochemical systems. Therefore, the research of lithium batteries has also promoted the development of electrochemical theory of non-aqueous systems. Except the use of various non-aqueous solvents, polymer thin film batteries has also been studied.Lithium batteries are widely used in energy storage systems such as hydropower, thermal power, wind power and solar power, telecommunications, electric vehicles, military equipment, aerospace and other fields.Lithium-ion batteries have been widely used in portable appliances such as laptop computers, video cameras, and mobile communications due to their unique performance advantages. With the shortage of energy and environmental protection, lithium battery is widely used in the electric vehicle industry, especially the emergence of lithium iron phosphate material batteries, which has promoted the development and application of the lithium battery industry. Ⅷ Questions Related to Lithium & Lithium-ion Batteries1. Is a lithium battery the same as a lithium ion battery?Lithium batteries feature primary cell construction. This means that they are single-use—or non-rechargeable. Ion batteries, on the other hand, feature secondary cell construction. This means that they can be recharged and used over and over again. 2. Do lithium-ion batteries need a special charger?Ultimately, using a battery charger with a specific Lithium charge algorithm is the best option for maximum performance and lifespan of any lithium battery. 3. Can you overcharge a lithium battery?In a lithium-ion battery, overcharging can create unstable conditions inside the battery, increase pressure, and cause thermal runaway. ... At best, this will lead to reduced capacity and shortened life cycle, and at worst this could cause thermal runaway. 4. Which is better lithium ion or lithium polymer battery?High powerBoth lithium-ion and lithium-poly batteries are suitable with high and robust power usages. However, lithium-ion batteries are more efficient and popular than lithium-polymer. They have higher energy levels and powers and are more suitable for heavy usages. 5. What is the difference between a lithium battery and a lithium-ion battery?Lithium batteries feature primary cell construction. This means that they are single-use—or non-rechargeable. Ion batteries, on the other hand, feature secondary cell construction. This means that they can be recharged and used over and over again.

IntroductionA printed circuit board (PCB) mechanically supports and electrically connects electrical or electronic components using conductive tracks, pads and other features etched from one or more sheet layers of copper laminated onto and/or between sheet layers of a non-conductive substrate. A PCB allows signals and power to be routed between physical devices.What are PCBs? How Do PCBs Work?CatalogIntroductionⅠ PCB Basics1.1 PCB MaterialsⅡ PCB Product CharacteristicsⅢ Common Sense of PCB ProcessⅠ PCB Basics1.1 PCB Materialsa. Copper Clad Laminate（referred to as CCL, or sheet material）Tg: Glass Transition Temperature, which is the temperature at which glassy substances are transformed between glassy and highly elastic (usually softened). In the PCB industry, this glassy substance is generally referred to as resin or dielectric layer composed of resin and glass fiber cloth. Tg is an important technical index reflecting the heat resistance of printed circuit board substrates. Generally, the higher the Tg value of printed circuit boards, the better the heat resistance. The Tg of general FR-4 copper-clad epoxy glass laminates for SMT printed circuit boards is 130 ～ 140℃, which can meet the requirements when using Sn-Pn solder. For lead-free solders with higher melting points, the Tg of the substrate can not withstand the high temperature of welding if the Tg ≤ 150 ° C. In special cases (high temperature use), the Tg can be greater than 170 ° C. However, excessive Tg will cause the hardness of the substrate to increase and the material to become brittle. Therefore, we cannot simply pursue high Tg. We should comprehensively consider the performance of the board and choose a suitable printed board substrate with a higher Tg, which is one of the requirements for lead-free welding.CTI: Comparative Tracking lndex (or comparative leakage index, tracking index). The highest voltage value that the surface of the material can withstand 50 drops of electrolyte (0.1% ammonium chloride aqueous solution) without the formation of leakage traces. The unit is V.CTE: Coefficient of thermal expansion. Generally, the sheet material performance of a PCB is measured by the linear expansion coefficient, which is defined as the ratio of the increase in length to the original length under a unit temperature change, such as Z-CTE. The lower the CTE value, the better the dimensional stability and vice versa.TD: Thermal decomposition temperature refers to the temperature at which the base material resin loses weight by 5%. It is a sign of delamination and performance degradation caused by the heat of the base material of printed circuit boards.CAF: Conductive Anodic Filament of printed boards is the phenomenon of electrochemical insulation damage on insulating substrates. It refers to the state where dendritic metals are precipitated between wires under the action of an electric field after a voltage is applied to parallel circuits on printed circuit boards. Or conductive anodic filament(CAF) occurs along the glass fiber surface of the substrate, thereby reducing the insulation between the wires.T288: It is a technical index that reflects the welding resistance of the printed circuit board substrate. It refers to the maximum time that the printed circuit board substrate can withstand the high temperature of welding at 288°C without blistering and delamination. The longer this time, the better it is for welding. For traditional Sn-Pb alloys with low welding temperature (220 ～ 230℃), when the thermal decomposition time of printed circuit board substrate is 260 ℃, T260≥30s can meet the requirements of SMT printed circuit board. For lead-free welding, the temperature is generally 250 ~ 260℃, the thermal decomposition temperature of the substrate of the printed circuit board will increase, and only T288≥300s at 288 ℃ can ensure that the substrate does not decompose and the performance is not damaged during welding.DK: dielectric constant.DF: Dissipation factor refers to the ratio of the energy that has been lost in the insulation sheet material of the signal line to the energy that still exists in the line.OZ: oz is the abbreviation of the symbol ounce, which is British measurement unit and also unit of weight. 1 OZ means the thickness of copper with a weight of 1 OZ evenly spread over an area of 1 square foot (FT2). It is the average thickness of copper foil expressed by the weight per unit area. It is expressed by a formula, that is, 1OZ = 28.35g / FT2. b. Copper FoilED Copper Foil: Electrodeposited copper, copper foil commonly used in PCB, cheap.RA Copper Foil: Rolled annealed copper, copper foil commonly used in FPC.Drum Side: smooth side of electrodeposited copper foilMatt Side: rough side of electrodeposited copper foilCopper: Elemental symbol Cu, atomic weight 63.5, density 8.89 g / cm3, and the electrochemical equivalent of Cu2 + is 1.186 g / Ah. c. Prepreg: referred to as PPEpoxy Resin: an organic polymer compound containing two or more epoxy groups in the resin molecule, which is a resin component used in prepregs that are currently commonly used.DICY: Dicyandiamide, a common hardenerR.C: resin contentR.F: resin flowG.T: gel timeV.C: volatile contentHarden: Under certain conditions (high temperature, high pressure or light), the epoxy resin and the hardener undergo cross-linking polymerization to form a polymer with a three-dimensional mesh structure. d. InkViscosity: Viscosity refers to the relative movement between adjacent fluid layers when fluid is flowing, and frictional resistance will be generated between the two fluid layers. Unit: Pascal. Seconds (pa.s).Hardness: The hardness of the ink after pre-baking is 2B, the hardness of the ink after exposure is 2H, and the hardness of the ink after finishing is 6H. Thixotropic: a property that the ink is gelatinous when it is left to stand, but its viscosity changes when it is touched. It is a physical property of a liquid, that is, its viscosity decreases under agitation, and it will return to its original viscosity soon after standing. By stirring, the thixotropic effect lasts for a long time and it is enough to reconstitute its internal structure. To achieve high-quality screen printing, the thixotropic of the ink is very important. In particular, during the squeegee process, the ink is agitated to make it liquid. This action speeds up the speed of ink passing through the mesh, and promotes the original ink with separate wires to be evenly integrated. Once the squeegee stops moving, the ink returns to a stationary state, and its viscosity quickly returns to the original required data. e. Dry Film· Structure of dry film Figure 1. Structure of Dry Film· Dry film consists of three parts and ingredients:   — Supporting film(Polyester)   — Photo-resist dry film   — Covering film(Polyethylene)· Main ingredients① Binder(film-forming resin) ②Monomer ③Photo-initiator ④Plasticiser ⑤Adhesion promoter ⑥Thermal polymerization inhibitor ⑦Dye ⑧Solvent· The types of dry film are divided into three types according to the different methods of developing and removing the dry film: solvent-based dry film, water-soluble dry film, and peel-off dry film; according to the purpose of dry film, it is divided into: dry resist film, masking dry film and solder mask dry film.· Photosensitivity: It refers to the amount of light energy required for the photoresist to react to form a polymer with a certain resistance under the irradiation of ultraviolet light. In the case of constant light source intensity and light distance, the sensing speed is expressed as the length of exposure time. Short exposure time means that the sensing speed is fast.· Resolution: refers to the number of lines (or intervals) that can be formed by the dry film resist within a distance of 1mm. The resolution can also be expressed by the absolute size of the lines (or intervals). f. Net YarnNet density:— T number \ mesh number: refers to the number of meshes within 1 cm. g. Drill bit· geometry structure name of drill bitFigure 2. Geometry Structure Name of Drill Bit· Point AngleThe point angle is composed of two narrow and long first point angle surfaces and two triangular hook-shaped second point angle surfaces. These four sides meet at the point angle, forming two short edges called chisel edges at the center of the joint. This is the place that the sheet material first touches. This chisel edge is first positioned under pressure and rotation to drill into the stack. A protruding square strip on each of the two outer sides of the first point angle surface is called a margin. This margin tends to spiral upward along with the drill body part, which is the contact part between the drill pin and the hole wall. The right angle at the intersection of the margin and the edge lip is very important to the quality of the hole wall. The point angle has a long edge between the first and second point angle surfaces. The point where the two long edges and the two chisel edges meet in the middle is the point angle. The angle formed by the two long edges is called the point angle. When the drilling paper is made of phenolic resin substrate, the drill point angle is about 90° ~ 110° due to less resistance. When drilling paper is FR4 glass fiber board, the point angle should be slightly blunt at 115° ~ 135°. The most common one is 130°. The angle between the first point angle surface and the horizontal plane of the long edge is about 15°, which is called primary face angle. The second point angle is about 30°, and the angle formed by the chisel edge and the edge lip is called a cheisel edge angle. · Types of drill bitFigure 3. Types of Drill Bit Ⅱ PCB Product Characteristics1) Impedance· The sum of resistance and reactance (capacitance, inductive reactance) on a vector. Common impedance types are characteristic impedance and differential impedance.2) Warpage· Maximum bow (Figure a) and twist (Figure b) of printed circuit boards using surface mount components should be less than or equal to 0.75%3) RoHSRoHS, the abbreviation of restriction of hazardous substances, is the restriction of the use of certain hazardous substances in electrical and electronic equipment. RoHS lists a total of six harmful substances, including: lead(Pb), cadmium(Cd), mercury(Hg), hexavalent chromium( Cr6+), polybrominated diphenyl ether(PBDE), polybrominated biphenyl(PBB).4) BacklightIt is an enlarged visual inspection method to check the integrity of the copper wall of the through hole. The method is to carefully thin the substrate outside the hole wall from a certain direction, and then use the principle of resin translucency to shoot light from the back. If the quality of the chemical copper hole wall is intact and there is no any holes or pinholes, the copper layer must be able to block light and be dark in the microscope. Once there are holes in the copper wall, light spots must appear and be observed , and can be enlarged as photographic evidence. The ground sample is about 4-6mm wide.Figure 5. Backlight Standard Diageam5) Anode Phosphor Copper Ball· Purity requirementsElementContent(%)ElementContent(%)Cu≥99.91Ni≤0.002P0.040-0.06Sb≤0.002Pb≤0.002As≤0.002Fe≤0.0025S≤0.002Sn≤0.002O≤0.002 · Features— A black (or brown-black) film forms on the surface of phosphor copper after power is applied.— Black (or brown-black) film is Cu3P, also called phosphor copper anode film.· Role of phosphor copper anode film— The anode film itself can catalyze and accelerate the (Cu+-E → Cu2+) reaction, thereby reducing the accumulation of CU+.— After the anode film is formed, it can inhibit the continuous generation of Cu+.— The electrical conductivity of the anode film is 1.5X104-1 cm-1, which has metal conductivity.— Phosphor copper is less anodized than pure copper (1A / DM2 P0.04-0.065%, phosphor copper is less anodized than oxygen-free copper, 50MV-80MV) and will not cause anode passivation.— Anode film will greatly reduce the phenomenon of tiny grains falling off the anode.— Anode film prevents the copper anode from dissolving too quickly.6) Method for Estimating Surface Area of Electroplated Copper Anode· Method for estimating surface area of round titanium basket copper anode: pDLF/2p = 3.14 D = diameter of titanium basket L = length of titanium basket F = factor· Method for estimating surface area of square titanium basket copper anode: 1.33LWFL = length of titanium basket W = width of titanium basket F = factor· F is related to the diameter of the copper ball:Diameter = 12 mm    F = 2.2Diameter = 15 mm    F = 2.0 Diameter = 25 mm    F = 1.7Diameter = 28 mm    F = 1.6 Diameter = 38 mm    F = 1.27) ICD IssuesInternal Connection Defects Ⅲ Common Sense of PCB Processa. Etching FactorThe index used to consider the amount of etching lateral erosion, because the amount of lateral erosion will be different for different copper thickness, so the etching factor is different from the total copper thickness.Calculation method:b. Lateral ErosionThe etching of the side wall of the wire under the resist pattern is called lateral erosion, and the degree of lateral erosion is expressed by the width of the side etching:· lateral erosion is related to the type, composition and etching process and equipment of the etching solution. c. Pool EffectDuring the etching process, the circuit board passes through the etching machine horizontally. Due to the gravity acting on it, the fresh medicine is blocked by the old one and cannot effectively react with the copper surface. d. Different Stages of ResinsA-stage resin: Some thermosetting resins are liquid in the early stages of manufacture or liquid when heated, and can still dissolve in some liquids at this time.B-stage resin: Some thermosetting resins can soften when heated in the middle stage of the reaction, but they cannot be completely dissolved or melted. At this time, they can swell or partially dissolve when contacted with some solvents.C-stage resin: The later stage of the reaction of some thermosetting resins, when it is practically insoluble or infusible. e. Font Color of SubstrateRed font: flame retardant grade, other fonts: non flame retardant grade. f. OthersMSDS: Material Safety Data Sheet provides a variety of information on safety, health and environmental protection for chemical substances and products, and can provide information on basic knowledge, protective measures and emergency actions of chemicals. In some countries, MSDS is also called SDS, and SDS terminology is used in ISO 11014.SGS: Societe Generale de Surveillance S.A. Founded in 1887, it is currently the world's largest and oldest non-governmental third party engaged in product quality control and technical certification of multinational companies. Headquartered in Geneva, it has 251 branches around the world, 256 professional laboratories and 27,000 professional and technical personnel, and carries out product quality inspection, monitoring and assurance activities in 142 countries.UL: UNDER WRITERS LABORATORIES INCIPC: The Institute for International and Packaging Electronic CircuitsISO: International Standards OrganizationMIL: Military StandardJPC: Japan Printed Circuit AssociationCOV: Coefficient of variationFR4: Abbreviation for Flame Retardant Type 4. It is the name of a flame-resistant printed circuit board material composed of a composite material of glass fiber and epoxy resin. It is the most widely used printed circuit board. g. pH ValueAlso known as the hydrogen ion concentration index and pH value, it is a scale of the hydrogen ion activity in a solution, which is a measure of the acidity and alkalinity of a solution in the usual sense. The concept was proposed by Danish biochemist Søren Peter Lauritz Sørensen in 1909. P stands for German Potenz, which means strength or concentration, and H stands for hydrogen ion (H +). Sometimes pH is also written in Latin as pondus hydrogenii.Under normal conditions (25°C, about 298K), when pH <7, the solution is acidic, when pH> 7, the solution is alkaline, and when pH = 7, the solution is neutral. h. Hull Cell TestHull designed Hull cell in 1939. The Hull cell test only requires a small amount of plating solution. After a short time test, the plating effect of the plating solution can be obtained in a wide range of current density. Because this test is sensitive to the composition and operating conditions of the plating solution, it is commonly used to determine the concentration and pH value of each component of the plating solution, and to determine the current density range for obtaining a good coating. The Hull cell has become an indispensable tool for electroplating research and electroplating process control.Hull cells are usually made of insulating materials such as plexiglass or rigid polyvinyl chloride. The bottom surface is trapezoidal, and the cathode and anode are placed on two sides that are not parallel. There are five types of capacity: 250ml, 267ml, 320ml, 534ml, and 1000ml. Generally, 250ml plating solution is often added to a 267ml test cell, which is convenient for converting the additives into how many grams per liter.Figure 8. Dimensions of Hull Celli. Current Density A / dm2A/dm2 — how many amperes per square decimeter area, 1A / dm2 — This is the current density of electroplating, which means that the current passes through the plating area of the workpiece per square decimeter is 1A and dm means decimeter. Generally, we use a 267ml Hull cell, place the test piece at the cathode and immerse it in the test solution. The area of the test piece is approximately 1dm2. j. TP: THROUGH POWERCalculation method:k. Replacement ReactionA replacement reaction is a chemical reaction in which a simple substance reacts with a compound to form another simple substance and a compound. Any replacement reaction is a metathesis reaction, including a reaction of metal and metal salt, the reaction of metal and acid, etc.; the replacement reaction must be a redox reaction, and the redox reaction is not necessarily a replacement reaction; the replacement reaction occurs according to the active list of metals. l. EDS：Energy Dispersive X-ray SpectroscopyThe surface of the sample being tested is irradiated with a condensed electron beam. Due to the interaction between the electron beam and the sample, various electrons or X-rays, photons, and other information are generated. Then, this information is collected and processed in different ways to display various characteristics of the sample (morphology, microstructure, composition, crystal plane, etc.) m. SEM：Scanning Electron MicroscopeAn electron beam with a diameter of 20 mm to 30 mm emitted from the cathode of the electron gun is accelerated by the voltage between the cathode and the anode, and is directed toward the lens barrel, and is condensed by the condenser lens and the objective lens, and is reduced into an electron probe with a diameter of about several nanometers. Under the action of the scanning coil on the upper part of the objective lens, the electron probe scans the surface of the sample in a raster pattern and excites a variety of electronic signals. These electronic signals are detected by corresponding detectors, amplified, converted into voltage signals, and finally sent to the grid of the picture tube and modulate the brightness of the picture tube. The electron beam in the picture tube is also raster scanned on the phosphor screen, and this scanning movement is strictly synchronized with the scanning movement of the electron beam on the sample surface, so that a scanning electron image corresponding to the contrast and the intensity of the received signal is obtained. The image reflects the topographical features of the sample surface. n. BONDINGBonding is a wiring method in the chip production process. It is generally used to connect the chip's internal circuit with gold or aluminum wires to the package pins or gold-plated copper foil on the circuit board before packaging. Ultrasonic waves from an ultrasonic generator (generally 40-140KHz), which generates high-frequency vibration through the transducer, are transmitted to the splitter through the horn. When the splitter is in contact with the lead wire and the welded part, under the action of pressure and vibration, the surfaces of the metal to be welded rub against each other, the oxide film is destroyed, and plastic deformation occurs, causing the two pure metal surfaces to closely contact each other to achieve the combination of atomic distance, and finally form a strong mechanical connection. After bonding (ie, after the circuit is connected to the pins), the chip is packaged with black glue. o. The Giovanni EffectIt means that due to the potential difference between two metals, an electric current is generated through the medium, and then an electrochemical reaction occurs, and the anode with a high potential is oxidized. p. Vacuum Degree; Degree of VacuumThe degree of thinness of the gas under vacuum is usually expressed by "high vacuum" and "low vacuum", high vacuum indicates "good" vacuum, and low vacuum indicates "poor" vacuum. If the pressure in the device under test is lower than atmospheric pressure, a vacuum gauge is required for pressure measurement. The value read from the vacuum gauge is called the degree of vacuum. The degree of vacuum is a value indicating that the actual value of the system pressure is lower than the atmospheric pressure, that is: the degree of vacuum = atmospheric pressure-absolute pressureThere are usually two ways to identify the degree of vacuum:   — First, it is marked with "absolute pressure" and "absolute vacuum degree" (that is, how much pressure is higher than "theoretical vacuum"); in actual cases, the absolute pressure value of the vacuum pump is between 0 and 101.325KPa. The absolute pressure value needs to be measured with an absolute pressure meter. The initial value of the gauge (absolute vacuum gauge) for measuring the vacuum degree at 20°C and the place where the altitude = 0 is 101.325KPa (ie, a standard atmospheric pressure).   — The second is to use "relative pressure" and "relative vacuum degree" (that is, how much pressure is lower than "atmospheric pressure") to identify. "Relative vacuum degree" refers to the difference between the pressure of the measured object and the atmospheric pressure at the measurement site and is measured with an ordinary vacuum gauge. In the absence of vacuum (that is, at atmospheric pressure), the initial value of the gauge is 0. When measuring vacuum, its value is between 0 and -101.325KPa (usually expressed as a negative number).Commonly used vacuum units are Pa, Kpa, Mpa, atmospheric pressure, kilogram (Kgf / cm2), mmHg, mbar, bar, PSI, etc. The approximate conversion relationship is as follows:   — 1MPa = 1000KPa   — 1KPa = 1000Pa   — 1 atmospheric pressure = 100KPa = 0.1MPa   — 1 atmospheric pressure = 1 kg (Kgf / cm2) = 760mmHg   — 1 atmospheric pressure = 14.5 PSI   — 1KPa = 10mbar   — 1bar = 1000mbar Frequently Asked Questions about PCB Basic1. What is PCB and types of PCB?A printed circuit board (PCB) is a thin board made from fiberglass, composite epoxy, or other laminate materials. PCBs are found in various electrical and electronic components such as beepers, radios, radars, computer systems, etc. Different types of PCBs are used based on the applications. 2. What is the basis of PCB?PCB is the acronym of Printed Circuit Board, a mechanical base that contains tracks and footprints reflecting the schematic of the design. Modern PCBs are typically made of a non-conductive substrate that is overlayed by copper layers. 3. What are the basic steps of PCB design?Here's the full list of PCB layout and design steps:Create the Schematic.Create a Blank PCB Layout.Schematic Capture: Linking to Your PCB.Designing Your PCB Stackup.Defining Design Rules and DFM Requirements.Place Components.Insert Drill Holes.Route Traces. 4. What are the common types of PCB?Common Types of Printed Circuit BoardsSingle Layer PCB. Single layer printed circuit boards are among some of the simplest to design and manufacture. ...Double Layer PCB.Multi-Layer PCB.High Density Interconnect (HDI) PCB.High Frequency PCB. 5. Which material is used in PCB?copper circuitryPrinted circuit boards (PCBs) are usually a flat laminated composite made from non-conductive substrate materials with layers of copper circuitry buried internally or on the external surfaces. They can be as simple as one or two layers of copper, or in high density applications they can have fifty layers or more.

FPGA (Field-Programmable Gate Array), it is the product of further development on the basis of PAL, GAL, CPLD and other programmable devices. It appears as a kind of semi-custom circuit in the field of application specific integrated circuit (ASIC). It not only solves the shortage of custom circuit, but also overcomes the shortcoming of limited number of gates in the original programmable devices.What is an FPGA, and how does it compare to a microcontroller?CatalogI. What is FPGA?II. Principles of FPGAs III. FPGA Pros & ConsIV. FPGA Chip StructureV. FPGA FeaturesFAQI. What is FPGA?FPGA (Field Programmable Gate Array) is a product of further development on the basis of programmable devices such as PAL and GAL. It emerged as a semi-custom circuit in the field of application-specific integrated circuits (ASIC), which not only solves the deficiencies of custom circuits, but also overcomes the shortcomings of the limited number of gate circuits of the original programmable devices.II. Principles of FPGAs FPGA adopts the concept of Logic Cell Array (LCA), which consists of Configurable Logic Block (CLB), Input Output Block (IOB) and Internal Interconnect. Three parts. FPGAs are programmable devices with a different structure than traditional logic circuits and gate arrays (such as PAL, GAL and CPLD devices). The logic of the FPGA is implemented by loading programmed data into the internal static memory cell, and the values stored in the memory cell determine the logic function of the logic cell and the connection between the modules or between the modules and the I/O. The value stored in the memory cell determines the logical function of the logic unit and the way the modules are linked to each other or to the I/O, and ultimately determines the functions that the FPGA can achieve.III. FPGA Pros & Cons - The Pros of FPGAs:(1) FPGAs consist of hardware resources such as logic cells, RAM, multipliers, etc. By organizing these hardware resources rationally, hardware circuits such as multipliers, registers, address generators, etc. can be implemented.(2) FPGAs can be designed by using block diagrams or Verilog HDL, from simple gate circuits to FIR or FFT circuits.(3) FPGAs can be infinitely reprogrammed, loading a new design solution in a few hundred milliseconds, reducing hardware overhead with reconfiguration.(4) The operating frequency of the FPGA is determined by the FPGA chip as well as the design, and can be modified by modifying the design or replacing it with a faster chip to meet certain demanding requirements (of course, the operating frequency is not unlimited and can be increased, but is governed by current IC processes and other factors).  - The Cons of FPGAs:(1) All functions of FPGAs rely on hardware implementation and cannot implement operations such as branching conditional jumping.(2) FPGAs can only implement fixed-point operations.To conclude: FPGAs rely on hardware to implement all functions and can be compared to dedicated chips in terms of speed, but there is a big gap in design flexibility compared to general purpose processors.IV. FPGA Chip StructureMainstream FPGA is still based on look up table technology, has far exceeded the basic performance of previous versions, and integrates common features (such as RAM, clock management and DSP). FPGA chips have seven main parts: programmable input/ output unit, basic programmable logic unit, complete clock management, embedded block RAM, rich wiring resources, embedded bottom functional unit and embedded special hardware module.The functions of FPGA chip structure are as follows:1. Programmable Input and Output BlockThe programmable input/ output block is referred to as I/ O port. It is the interface part between the chip and the external circuit, which can drive and match the input/ output signals under different electrical characteristics. I/ O in FPGA is classified by group, and each group can support different I/ O standards independently. With the flexible configuration of the software, different electrical standards and I/ O physical characteristics can be met, the drive current can be adjusted, and the frequency of I/ O port of the and pull-up resistor and pull-down resistor can be changed, so that the frequency of the I/ O port can be higher and higher. Some high-end FPGA can support data rate up to 2Gbps through DDR register.Fig 1. IOB Internal Structure DiagramThe external input signal can be read into the FPGA through the memory cell of the IOB module, or directly written into the inside of the FPGA. When the external input signal passes through the memory cell of the IOB module read into the inside of the FPGA, the requirement of hold time  can be reduced, which usually the windows default is 0.In order to facilitate management and adapt to a variety of electrical standards, FPGA's IOB is divided into several banks, each bank interface standard is determined by its interface voltage VCCO, in addition, a bank can only have one VCCO, but each bank VCCO can be different. Only ports with the same electrical standard can be connected together, and the same VCCO voltage is the basic requirement of the interface standard.2. Configurable Logic Block (CLB)CLB is the basic logical unit within the FPGA. The actual number and characteristics of CLBs vary depending on the device, but each CLB contains a configurable switch matrix that consists of 4 or 6 inputs, some lectotype circuits (multiplexers, etc.) and flip-flops. The switch matrix is highly flexible and can be configured to work with combinational logic, shift registers, or RAM. In Xilinx's FPGA device, the CLB consists of multiple (usually 4 or 2) identical Slices and additional logic. Each CLB module be used to realize combinational logic and sequential logic, and it can also be configured as distributed RAM and distributed ROM.Fig 2. CLB Structure DiagramSlice is a basic logical unit defined by Xilinx. A Slice consists of two 4-input functions, carry logic, arithmetic logic, storage logic and function multiplexer. Arithmetic logic includes a  XORG and a MULTAND. XORG enables a Slice to implement the full operation of 2bit, and MULTAND improves the efficiency of multipliers. Carry logic consists of a dedicated carry signal and a function multiplexer for fast arithmetic addition and subtraction operations; 4-input functions generator is used to implement the 4-input LUT, distributed RAM or 16-bit shift register. Carry logic includes two fast carry chains to improve the processing speed of the CLB module.Fig 3. Inputting Slice Structure Diagram3. Digital Clock Management (DCM)Most of the industry's FPGA offer digital clock management. FPGA offers digital clock management and phase loop locking. Phase loop locking can provide accurate clock synthesis, reduce jitter and achieve filtering.4. Block Random Access Memory (BRAM)Most FPGAs have embedded block RAM, which greatly extends the applications and flexibility of the FPGA. The block RAM may be configured as a single-port RAM, a dual-port RAM, a content address memory (CAM), and a common storage structure such as a FIFO. CAM memory has a comparison logic in each of its internal memory cells, the data written into the CAM will be compared with each of the data in the interior, and the address of all data that is the same as the port data, so that there is a wide range of address switches in the route application. In addition to the block RAM, the LUT in the FPGA can be flexibly configured as a RAM, a ROM, and a FIFO. In practical application, that number of block RAM in the internal block of the chip is also an important factor in the chip selection.The capacity of the monolithic RAM is 18k bits, that is, the bit width is 18 bits and the depth is 1024. It can change the bit width and depth according to the need, but two principles must be satisfied: firstly, the modified capacity (bit width depth) cannot be greater than 18k bits; Second, the maximum bit width cannot exceed 36 bits. Of course, it is possible to concatenate multiple blocks of RAM to form a larger RAM, which is limited only by the number of RAM blocks in the chip and is no longer constrained by the above two principles.5. Wiring SourceAll the parts are connected with wiring resources in the FPGA, and the length and process of the connection determine the driving ability and the transmission speed of the signal on the wire. There are abundant wiring resources in the FPGA chip, according to the process and length, width and distribution position, which are divided into 4 different categories. First is the global routing resource, which is used for the internal global clock and the global reset/ position routing. Second is the long line resource, which is used to complete the wiring of the high-speed signal and the second global clock signal between chip banks. Third is short-line resources, which are used to perform logical interconnection and cabling between basic logical units. Fourth is a distributed wiring resource, which is used as control signal lines for a proprietary clock or a reset.In practice, the designer does not need to select the routing resources directly, and the layout scheduler can automatically select the better routing resources according to the topology of the input logical grid table and constraint conditions to connect each module unit. In essence, the use of routing resource types has a close and direct relationship with the results of the design.6. Underlying Built-in Function The underlying built-in function mainly refers to a DLL (Delay Locked Loop), a PLL (Phase Locked Loop), a DSP, and a CPU, which belong to core softcore. The more and more built-in functional units make the single-chip FPGA a system-level design tool, so that it has the capability of joint design of hardware and software, and gradually turn to the SOC platform.DLL and PLL have similar functions, such as high-precision clock and low jitter frequency doubling and frequency division, duty cycle adjustment and phase shift, etc. Xilinx integrated the DLL, Altera made the PLL, Lattice combined both two, which can be easily managed and configured through IP core-generated tools on Lattice's new chip. Fig 4. Typical DLL module schematics7. Special Built-in Hard CoreThe embedded special hard core is relative to the soft core embedded in the bottom, which means that the hard core with strong processing ability of FPGA is equivalent to the ASIC. To improve FPGA performance, chip manufacturers integrate some dedicated hard cores on the chip. For example, to improve the multiplication speed of FPGA, special multipliers are integrated in the mainstream FPGA, and in order to match the communication bus and interface standard, a lot of high-end FPGA are integrated SERDES, which can achieve the receiving and dispatching speed of  Gbps. V. FPGA Features1) The ASIC circuit is designed by adopting the FPGA, and the user does not need to put the chip into production, so that a shared chip can be obtained.2) FPGA can be used as a trial sample of other fully customized or semi-custom ASIC circuits.3) There are rich flip-flops and I/ O pins within the FPGA.4) FPGA is one of the devices with the shortest design cycle, the lowest development cost and the least risk among ASIC circuits.5) FPGA adopts high-speed CMOS process, low power consumption, and can be compatible with CMOS and TTL.It can be said that FPGA chip is one of the best choices for small batch system to improve system integration and reliability.The working state of FPGA is set by the program stored in the on-chip RAM, so it is necessary to program the on-chip RAM when working. Users can use different programming methods according to different configuration modes.When the power is on, the FPGA chip reads the data from the EPROM into the on-chip programming RAM. After the configuration is completed, the FPGA enters the working state. After power off, FPGA internal logic disappears. Therefore, FPGA can be programmed repeatedly. And the programming of FPGA does not require a special programmer, a general-purpose EPROM or PROM programmer can meet the requirement. When you need to modify the FPGA functionality, just replace a piece of EPROM. In this way, the same piece of FPGA, with different programming data, can produce different circuit functions. Therefore, the use of FPGA is very flexible.FAQ 1. What is FPGA and why it is used?FPGA Basics: Architecture, Applications and Uses. The field-programmable gate array (FPGA) is an integrated circuit that consists of internal hardware blocks with user-programmable interconnects to customize operation for a specific application.2. Is FPGA faster than CPU?They also found that using custom FPGAs to implement the Rowhammer exploit would cause far more of the "bit flips" that they wanted to see. A FPGA can hit the data cell faster and more often than a CPU can do it meaning the FPGA causes more results to occur during an attack. It all goes faster when an FPGA is used.3. Are FPGAs dead?Yes, it's a dead end. If you enjoy creating hardware, RTL design targeting FPGAs is still a good choice (although there is a huge amount of effort here to make it more like creating software than hardware).4. What are FPGAs good for?FPGAs are particularly useful for prototyping application-specific integrated circuits (ASICs) or processors. An FPGA can be reprogrammed until the ASIC or processor design is final and bug-free and the actual manufacturing of the final ASIC begins. Intel itself uses FPGAs to prototype new chips.5. Is FPGA a microprocessor?Microprocessors are more complex than FPGAs. Microprocessors have fixed instructions while FPGAs don't. FPGAs and microprocessors are often mixed into a single package.6. What are the advantages of FPGA?FPGA advantages:Long-term availability.Updating and adaptation at the customer.Very short time-to-market.Fast and efficient systems.Acceleration of software.Real-time applications.Massively parallel data processing.7. Why is FPGA slow?FPGAs tend to get faster in max speed, but the limit actually has to do with process variation affecting static timing. The chips have to have a soultion that works on all of them. So you lose performance of the device to make sure any device will work with it. And as your design gets bigger it runs slower.8. What are the disadvantages of FPGA?Drawbacks or disadvantages of FPGA:The programming is not as simple as C programming used in processor based hardware. Moreover engineers need to learn use of simulation tools. ➨The power consumption is more and programmers do not have any control on power optimization in FPGA. No such issues in ASIC.9. Can FPGA replace CPU?There will always be a need for a general purpose CPU to run most things, and while you can implement a CPU on an FPGA, that gives you the worst of both worlds - no improvement from specialised hardware design, and you still need to pay the “FPGA tax”. So no, FPGAs will never replace CPUs.10. Why use an FPGA vs microcontroller?A FPGA can be used if the design requires complex logic and requires high processing ability and if the cost is comparable to the performance achieved. In case of a design that requires limited hardware, and is set to perform only some specific functions, then Microcontroller is preferred.

Introduction FPGA is a product of further development on the basis of programmable devices such as PAL, GAL, and CPLD. It appears as a semi-custom circuit in the field of application specific integrated circuits (ASIC), which not only solves the shortcomings of the custom circuit, but also overcomes the limited number of gate circuits of the original programmable device. FPGA is often used in communication, network and other fields to process a large number of network data packets. It is also widely used in aerospace, military defense and other fields. As a hardware test platform before other chips are taped out, it plays an important role in cloud computing, artificial intelligence (AI) and other fields. FPGA Applications, Features and Selection Catalog Introduction Ⅰ FPGA Basic Architecture Ⅱ FPGA Basic Features Ⅲ FPGA Applications 3.1 Circuit Design 3.2 Product Design 3.3 System Application Ⅳ Vacuum Cleaner Based on FPGA 4.1 A Short Brief 4.2 The Composition of the Platform 4.3 Main Hardware Design 4.4 Program Design Points Ⅴ FAQ Ⅰ FPGA Basic Architecture FPGA consists of 6 parts, namely programmable input/output (I/O) unit, basic programmable logic unit, embedded RAM, abundant wiring resources, bottom embedded functional unit and embedded dedicated hard core. Figure 1. FPGA Basic Architecture Each unit is described as follows:🔺Programmable I/O UnitAt present, most FPGA I/O units are designed in programmable mode, that is, through the flexible configuration of software, they can adapt to different electrical standards and I/O physical characteristics; the matching impedance characteristics, the pull-up and pull-down resistors can be adjusted; the output drive current can be adjusted, etc.🔺Basic Programmable Logic UnitThe basic programmable logic unit of FPGA is composed of a look-up table (LUT) and a register. The look-up table completes the pure combinational logic function. FPGA internal registers can be configured as flip-flops with synchronous/asynchronous reset and set, clock enabled, or as latches. FPGA generally relies on registers to complete synchronous sequential logic design. Generally speaking, the configuration of a classic basic programmable unit is a register plus a LUT. However, the internal structures of registers and look-up tables of different manufacturers are different, so the combination modes are also different.An important aspect of learning the LUT and Register ratios of the underlying hive is device selection and sizing. In addition to the basic programmable logic units inside the FPGA, there are embedded RAM, PLL or DLL, dedicated Hard IP Core, etc. These modules can also be equivalent to a certain scale of system gates, so the simple and scientific method is use the number of Registers or LUTs of the device to measure.🔺Embedded RAMNow most FPGAs have embedded RAM, which can be configured as single-port RAM, dual-port RAM, pseudo-dual-port RAM, CAM, FIFO and other storage structures.CAM is the content address memory. The data written to the CAM is compared with every data stored in it and returns the addresses of all internal data that are the same as the port data. Simply put, RAM is a storage unit for writing addresses and reading data, while CAM is just the opposite of RAM. In addition to block RAM, Xilinx and Lattice FPGAs can flexibly configure LUTs into storage structures such as RAM, ROM, and FIFO.🔺Rich Wiring ResourcesThe routing resources connect all the units in the FPGA, and the length and process of the connection determine the driving ability and transmission speed of the signal on the connection. Here the division of wiring resources:1) Full dedicated routing resources: Complete the routing of the global clock and global reset/set within the device.2) Long-term resources: Used to complete the wiring of some high-speed signals and some second global clock signals between device banks.3) Short-circuit resources: Used to complete the logic interconnection and wiring between basic logic units.4) Others: There are various wiring resources and control signal lines such as dedicated clock and reset in the logic unit.In the design process, the place and router often automatically selects the available routing resources to connect the underlying unit modules used according to the topology and constraints of the input logic netlist, so routing resources are often ignored. In fact, the optimization of routing resources is directly related to the use and implementation results.🔺The bottom layer is embedded with functional units, and the resources embedded by different manufacturers will be different.🔺Embedded dedicated hard coreDifferent from the "low-level embedded unit", the hard cores here are mainly those with relatively weak generality, and not all FPGA devices contain hard cores.   Ⅱ FPGA Basic Features 1) Using FPGA to design ASIC circuit (application-specific integrated circuit), users can get suitable chips without film production.2) FPGA can be used as a mid-scale sample for other full-custom or semi-custom ASIC circuits.3) There are abundant triggers and I/O pins inside the FPGA.4) FPGA is one of the devices with the shortest design cycle, the lowest development cost and the lowest risk in the ASIC circuit.5) FPGA adopts high-speed CMOS technology with low power consumption and is compatible with CMOS and TTL levels. Figure  2. FPGA Chip Ⅲ FPGA Applications 3.1 Circuit Design Connection logic and control logic are the areas where FPGA played a relatively important role in the early days and are also the cornerstone of FPGA applications. In fact, it is still quite difficult to apply FPGA in circuit design, which requires developers to have corresponding hardware knowledge (circuit knowledge) and software application capabilities (development tools). So talents in this area are always in short supply, and they are often engaged in new technologies. The successful product development of new products will become the mainstream basic products in the market for designers to apply. In the near future, the design of general-purpose and special-purpose IP will become popular. 3.2 Product Design Apply relatively mature technology to some specific fields such as communication, video, information processing, etc. to develop products that meet the needs of the industry and can be accepted by industry customers. This aspect is mainly a combination of FPGA and professional technology. In addition, there are product design for interface issues with professional customers also includes professional tool products and civilian products. The former focuses on performance, while the latter focuses on price-sensitive product design to achieve product functions as the main purpose.FPGA is a means of realization. In this field, it has the characteristics of interface, control, functional IP, embedded CPU, etc. to realize a system product design with simple structure, high degree of curing, and comprehensive functions for FPGA market. 3.3 System Application The system-level application is the combination of FPGA and traditional computer technology to realize an FPGA version of the computer system. For example, Xilinx V-4, V-5 series FPGA is used to realize the embedded POWER PC CPU, and then cooperate with various peripheral functions. To achieve a basic environment, running LINUX and other systems on this platform also supports various standard peripherals and functional interfaces, which is very helpful for quickly forming large-scale FPGA systems.In system-level applications, if the developers do not have the ability to expand the system, it is meaningless to just engage in programming. Of course, the development of device drivers is another case. The system-level application seems to have a high starting point, but it does not have deep development ability, it is likely to become a hobbyist, just like many people can make web pages but cannot be called programming.   Ⅳ Vacuum Cleaner Based on FPGA 4.1 A Short Brief Design of indoor intelligent vacuuming platform based on FPGA.Intelligent environmental cleaners have increasingly become the focus of research because they can replace people in environmental cleaning. Although they achieve intelligence, most of them have complex structures and high integration, which are not conducive to developers to expand their functions. On the basis of researching and summarizing the relatively mature products on the market, this paper designs and implements an indoor intelligent vacuuming platform based on a highly programmable FPGA. The platform has self-navigation, can clean most of the space, and is compact in shape, stable in operation and low in noise. More importantly, it has a simple structure and a user-friendly interface, which is convenient for further development of operation and functions. Figure  3. Body Frame 4.2 The Composition of the Platform The overall frame design of the platform proposed in this paper is shown in Figure 3, and a car with four wheels is used as the carrier of the entire platform. The FPGA controller is used as the main controller of the entire platform, and is connected to the photoelectric sensors jk1, jk2, jk3, jk4 and the collision switch jk5 through I/O to realize the detection of platform obstacles. Then output PWM waveform through I/O to drive speakers and high-low, and the change of the level drives the on and off of the LED to form an acousto-optic circuit. Finally the stepper motor dj1, dj2 and the DC dust collection motor dj3 are driven by controlling the signal control line of the motor driver to realize the movement and dust collection of the platform. 4.3 Main Hardware Design The system is mainly composed of FPGA main control chip, photoelectric sensor, collision switch, wireless remote control transmitter module controlled by two STC89C52 microcontrollers, two mode selection chips, acousto-optic circuit, drive motor, vacuum cleaner motor and the power supply circuit of the whole system, such as as shown in the Figure 4. Figure  4. Main Control System 🔺FPGA Chip SelectionAccording to the overall design of the platform, the basic requirements for the chip can be drawn:(1) At least 6 PWM waveform outputs are required.(2) One serial communication interface is required.(3) A real-time chip that requires a higher 12 V to be converted to 3.3 V.(4) Higher processing speed.(5) There are more I/O interfaces.Taking these conditions into consideration, the EP2C35F672C6 model in the CycloneII series FPGA produced by Altera can basically meet the requirements. It has excellent operation speed, low cost and DSP module, large internal memory, multi-channel PWM output, flexible design and comprehensive use of multiple languages, and the cost performance is relatively high.🔺Configuration Circuit Design Points(1) Power supply circuit: The power supply system uses 12V power supply as the input power supply, uses L7805CV to step down it to 5V, and then converts 5V to 3.3V and 1.2V by TPS37HD301. The power supply point of the I/O port of the FPGA is 3.3V, the core supply voltage is 1.2V. Because the motor drive system uses the 5V signal of the controller, and the port voltage of the FPGA is 3.3V, the I/O voltage must be boosted to 5V, and the 74HCT245 boost chip is used here.(2) Clock and reset circuit: ZPB-26-16 M is an active crystal oscillator in the clock circuit, and the frequency is 16MHz, which makes the serial port baud rate more accurate. At the same time, it can support the PPL function and ISP download function inside the chip. The reset circuit takes hardware reset and software reset.(3) Debug JTAG and download circuit: Because the soft core ISP and JTAG can be built directly inside the FPGA, the hardware circuit is connected to a JTAG interface of IDC-10.(4) Configuration storage circuit: EPCS16 is selected as the ROM of the FPGA, which can be repeatedly programmed by the download cable or other equipment, and can also be programmed online through the AS interface. Use the 4MHz On-Chip memory inside the FPGA chip as the RAM of the FPGA.(5) Sensor and collision switch: E3F-DS5C4.P1R photoelectric switch, used to detect obstacles and stairs, which is a cylindrical diffusion type with a maximum distance of 5cm, or an adjustable NPN type normally open photoelectric switch. The collision switch mainly cooperates with the front sensor to protect the front of the platform. When the platform hits the obstacle ahead, trigger the switch to make the platform avoid the obstacle.(6) Wireless sending and receiving module: XL02-232AP1 wireless module is a half-duplex wireless transmission module with UART interface, which can work in the 433MHz public frequency band and meet the wireless regulatory requirements.(7) Drive and vacuum motor: The platform adopts the front wheel dual drive, the motor selects the two-phase hybrid stepping type, and the vacuum cleaner motor adopts the DC motor. The main electrical parameters of the stepping motor are: ① Step angle: 1.8°② Phase current: 0.87 A③ Holding torque: 0.24 nm④ Phase resistance: 3.3 Ω⑤ Phase inductance: 5.0 mH⑥ Weight: 0.2 kg(8) Sound and light circuit and automatic cleaning time input display circuit: The sound and light circuit is mainly composed of light-emitting diodes and buzzers, which are directly connected to the FPGA to remind the working state of the platform. Use 4 buttons (OK, Initial, Up, Down) to input the cleaning time, and then three digital tubes display the set time. The cleaning time is counted by the timer inside the FPGA. When the timer is completed, the platform stops working. 4.4 Program Design Points Divide the program into two parts: hardware programming and software programming. For hardware programming, timing simulation of hardware circuits is required to determine the effect of debugging.🔺Hardware Programming and SimulationThe platform mainly generates input signals through sensors and collision switches, and processes the signals through FPGA. Finally, the FPGA transmits the processed signals to the motor, and the motor completes a series of actions, as shown in Table 1. So its logic design is the key to realize intelligence. After the hardware selection is completed, use Quartus II to build the hardware schematic diagram. After compiling, perform timing simulation on jk1, jk2, jk3, and jk4, analyze the timing relationship, estimate the performance of the design, and check and eliminate competition risks.Table 1: Relationship between Motor Status and Platform Working Status. dj1 dj2 dj3 Cleaner Status Turn Forward Turn Forward ON Vacuuming Forward Turn Back Turn Forward ON Vacuuming Left Turn Forward Turn Back ON Vacuuming Right Turn Back Turn Back ON Vacuuming Back The realization of platform work in automatic cleaning mode depends on the cooperative work of sensors (jk1, jk2, jk3, jk4) and motors (dj1, dj2, dj3), and the logical relationship is designed according to their functions.Table 2: Relationship between Sensor Status and Platform Working Status. jk1 jk2 jk3 jk4 Cleaner Status 1 1 1 1 Vacuuming Forward 1 1 0 1 Vacuuming Left 1 0 1 1 Vacuuming Right 1 0 0 1 Vacuuming Forward 0 1 0 1 Vacuuming Forward (Turn 90° Left)  0 0 1 1 Vacuuming Forward (Turn 90° Right)  0 0 0 1 Vacuuming Back When the hardware selection is completed, use Quartus II to build the hardware schematic diagram. After compiling, perform timing simulation on jk1, jk2, jk3, and jk4 to analyze the timing relationship.🔺Software ProgrammingAfter the hardware design and debugging is completed, the software system design is also carried out. Write a C program in a C language file to program the SoPC. The overall algorithm flow of the platform work is shown in Figure 5. When the platform is powered on, firstly enter the automatic cleaning and manual remote cleaning mode. After the automatic cleaning mode is selected, input the working time of the platform's automatic cleaning through the keyboard, and use the sensor to judge whether it encounters obstacles or stairs during the cleaning process. Through the interrupt, check whether the set time is reached at all times. If not, the program will return to running. However, if the set time is up, the program will end and the platform will stop working. When remote cleaning is selected, platform movement is controlled by the operator. Figure 5. Algorithm Flowchart Through hardware selection, construction and debugging, and software language writing and debugging, a simple platform has been successfully made, and various predetermined functions have been realized. Compared with similar products on the market, its structure is simpler, the cost is lower, the flexibility and scalability are stronger, and it provides a hardware-supported platform for researchers to develop more functions, which has practical value. As microprocessors continue to advance and sensing technology evolves, their performance can continue to improve and costs can continue to decline. However, in the process of simulation and implementation, it is found that its specific process algorithm is not rigorous enough, and it is necessary to continue to improve it in the future.   Ⅴ FAQ 1. What is FPGA architecture?The field-programmable gate array (FPGA) is an integrated circuit that consists of internal hardware blocks with user-programmable interconnects to customize operation for a specific application. 2. What are the parts of an FPGA?Structure of an FPGAConfigurable Logic Block (CLB)Digital Signal Processing (DSP) Slice.Transceivers.Block Random Access Memory (BRAM)Input/Output (IO) Blocks. 3. What is a basic unit of an FPGA?The configurable logic blocks (CLBs) are the basic logic unit of an FPGA. Sometimes referred to as slices or logic cells, CLBs are made up of two basic components: flip-flops and lookup tables (LUTs). 4. What is FPGA and its types?FPGA stands for Field Programmable Gate Array which is an IC that can be programmed to perform a customized operation for a specific application. They have thousands of gates. In the field of VLSI FPGAs have been very popular. 5. What is the function of FPGA?FPGAs are mainly used to design application-specific integrated circuits (ASICs). First, you design the architecture of such a circuit. Then, you use an FPGA to build and check its prototype. Errors can be corrected. 6. What is FPGA and its application?The FPGA is Field Programmable Gate Array. It is a type of device that is widely used in electronic circuits. FPGAs are semiconductor devices which contain programmable logic blocks and interconnection circuits. It can be programmed or reprogrammed to the required functionality after manufacturing. 7. What are the advantages of FPGA?FPGA advantagesLong-term availability.Updating and adaptation at the customer.Very short time-to-market.Fast and efficient systems.Acceleration of software.Real-time applications.Massively parallel data processing. 8. What is inside CLB in FPGA?A configurable logic block (CLB) is the basic repeating logic resource on an FPGA. When linked together by routing resources, the components in CLBs execute complex logic functions, implement memory functions, and synchronize code on the FPGA. 9. What are the main applications of FPGAs?Main FPGA applications are: Medical, video & image processing, telecom & datacom, server & cloud and defense and space. FPGA chips are used in both wired and wireless communications. 10. What are the industrial applications of FPGA boards?Such applications include multiple sensor dome cameras, HD (High Definition) cameras, night-vision cameras, etc. FPGAs provide the differentiation factor and the processing power to implement such complex solutions. 11. What are the applications of CPLDs and FPGAs?Applications of CPLDCPLDs can be used as bootloaders for FPGAs and other programmable systems. CPLDs are often used as address decoders and custom state machines in digital systems. Due to their small size and low power consumption, CPLDs are ideal for use in portable and handheld digital devices. 12. What programmable technology is used in a FPGA devices?FPGA emerged from relatively simpler technologies such as programmable read-only memory (PROM) and programmable logic devices (PLDs) like PAL, PLA, or Complex PLD (CPLD). It consists of three main parts: Configurable Logic Blocks — which implement logic functions. Programmable Interconnects — which implement routing. 13. What are the features of FPGA?The basic features of FPGA are: 1) FPGA design ASIC circuit, the user does not need to chip production, you can get a combination of chips. - 2) FPGA can do all other custom or semi-custom ASIC circuit of the sample sample. 3) FPGA has a rich internal trigger and I / O pin. 14. Is a FPGA a computer?An FPGA is a chip consisting of a series of logic blocks which can be modified and configured by the user. ... FPGA are programmable chips and their functionality can be updated multiple times. FPGAs come in array of size and prices and are most likely used in low-mid size volume products.

IntroductionA voltage regulator is a circuit that generates a fixed output voltage of a preset magnitude that remains constant regardless of changes to its input voltage or load conditions. It converts an unstable dc voltage into a stable dc voltage. Its power supply composed of discrete components has the advantages of large output power and wide adaptability. In recent years, integrated regulated power supplies have been widely used. Among them, three-terminal series regulators are the most common for low-power regulated power supplies. The commonly used integrated voltage regulators in the circuit mainly include 78xx series, 79xx series, adjustable integrated voltage regulator, precision voltage reference integrated voltage regulator, etc.What is a Voltage Regulator and How Does It Work?CatalogIntroductionⅠ Voltage Regulator ClassificationⅡ Main ParametersⅢ Applying NotesⅣ Typical Examples: LM317 & LM7805Ⅰ Voltage Regulator ClassificationVoltage regulators are generally divided into linear voltage regulator and switching voltage regulator. Linear voltage regulator is a circuit used to maintain a steady voltage, which is divided into low dropout type and general dropout type. Switching voltage regulator is a type of switch mode power supply circuit that is designed to efficiently reduce dc voltage from a higher voltage to a lower one, which is divided into step-down type, step-up type and integrated type with opposite input and output polarity.According to the number of outlet terminals and usage of the voltage regulator, it can be roughly divided into three-terminal fixed type, three-terminal adjustable type, multi-terminal adjustable type and single-chip switch type.The three-terminal fixed type voltage regulator integrates sampling resistors, compensation capacitors, protection circuits, high-power adjustment tubes, etc. on a chip. So that the entire integrated circuit block has only 3 terminals: input, output and public. It is very convenient to use. Its disadvantage is that the output voltage is fixed, so a series of products with various output voltages and current specifications must be produced to match.The three-terminal adjustable integrated voltage regulator only needs two external resistors to obtain various output voltages.The multi-terminal adjustable type is an early integrated voltage regulator. With small output power and many pins, it is not convenient to use, but the precision is high and the price is cheap.The monolithic switch type integrated regulated power supply develops in recent years, and its efficiency is particularly high. Its working principle is different from the above three types. It is a converter that converts DC to AC (high frequency) and then DC. Usually there are two types of pulse width modulation and pulse frequency modulation, and the output voltage is adjustable.Ⅱ Main Parameters1) Voltage Regulation RateIt is an important indicator that characterizes the voltage regulation performance of the integrated voltage regulator, also known as the voltage regulation coefficient or stability. It represents how stable the output voltage V0 of the regulator is when the input voltage V1 changes.2) Current Regulation RateIt is also known as current stability coefficient, and shows the ability of the regulator to suppress output voltage fluctuations caused by changes in load current (output current) when the input voltage remains unchanged.3) Ripple Rejection RatioIt reflects the ability of the regulator to suppress the mains ripple voltage introduced at the input.4) Output Voltage Temperature CoefficientIt is also known as the output voltage temperature change rate, and refers to when the input voltage and output current (load current) remain unchanged, the output voltage of the regulator changes with temperature.5) Long-term Stability of the Output VoltageIt refers to the magnitude of the change in the output voltage value over time (when the output current, input voltage and ambient temperature remain unchanged). It is usually the maximum amount of change in the output voltage of the regulator within a specified time.6) Output Noise VoltageIts absolute value represents the noise performance of the regulator directly. There is also a percentage value of the output noise voltage Vn and the output voltage V0 of the regulator to characterize the noise performance.7) Thermal StabilityIt refers to the thermal stability of the voltage regulator. It is usually the percentage value of the relative change in the output voltage caused by its unit power consumption.8) Temperature StabilityIt is the percentage value of the relative change of the regulator's output voltage within the specified maximum change range of operating temperature. Ⅲ Applying Notes① There are many types of integrated voltage regulator. According to the adjustment method there are linear and switch type. Based on the output method, there are fixed and adjustable types. Because of the obvious advantages of the three-terminal voltage regulator, it is more convenient to use and operate.② Before connecting to the circuit, it is necessary to distinguish the pins and their functions to avoid damage to the integrated block. The input and output ends of the three-terminal integrated voltage regulator with an output voltage greater than 6v need to be connected with protective diodes to prevent the rapid discharge of the output capacitor, which will cause damage to the three-terminal integrated voltage regulator when the input voltage drops suddenly.③ In order to ensure the stability of the output voltage, the minimum input voltage difference should be guaranteed. For example, the minimum pressure difference of the three-terminal integrated voltage regulator is about 2v, and it should be kept above 3v during general use. At the same time, it should be noted that the maximum voltage difference of input and output does not exceed the specified range.④ In order to expand the output current, the three-terminal integrated voltage regulator is allowed to be used in parallel.⑤ When using, the welding should be firm and reliable. If a heat dissipation device is required, it should meet the required size.If you have a bad regulator, it may cause many components such as the fuel pump, ignition system, or other parts which require a minimum amount of voltage to not function correctly. You may experience the engine sputtering, a rough idle, or simply a lack of acceleration when you need it. Ⅳ Typical Examples: LM317 & LM7805The LM317 device is an adjustable three-terminal positive-voltage regulator capable of supplying more than 1.5 A over an output-voltage range of 1.25V to 37V. It serves a wide variety of applications including local, on card regulation. This device can also be used to make a programmable output regulator, or by connecting a fixed resistor between the adjustment and output, the LM317 can be used as a precision current regulator.LM317 Specifications Adjustable output voltage as low as 1.2VOutput voltage: 1.25-37V DCGuaranteed 1.5A output currentOutput current: 5mA-1.5ATypical linear adjustment rate: 0.01%Max input-output voltage difference: 40V DCTypical load regulation rate: 0.1%Min input-output voltage difference: 3V DCRipple rejection ratio: 80dBOperating temperature: -10± 85℃Output short circuit protectionStorage temperature: -65± 150℃Over-current, overheat protectionOutput voltage: 1.25-37V DCAdjusting tube safe working area protectionOutput current: 5mA-1.5A The linear voltage regulator LM7805 has over-voltage protection, over-current protection, and over-heat protection functions, which makes its performance very stable. It is a 5V regulator, and is able to achieve output current above 1A, and has a good temperature coefficient. So the product has a wide range of applications. Have a look to get more specific info by the following video:Why is the LM7805 is a very Popular Voltage Regulator?As a member of 78xx series of fixed linear voltage regulators, the following is a very good summary of the basics on linear voltage regulator 7805:ParameterSymbolConditionsMinTypicalMaxUnitOutput VoltageVoTj=25℃4.85.05.2V5.0mA<Io<1.0APo<15WVi=7v to 20v4.755.05.25VLinear Adjustment rate△VlineTj=25℃, Vi=7V to 25V 3.0100mVTj=25℃Vi=8V to 12V 1.050mVLoad Adjustment Rate△VloadTj=25℃,lo=5.0mA to 1.5A  100mVTj=25℃lo=250mA to 750mA  50mVStatic CurrentIqTj=25℃  8mAStatic Current Rate△Iqlo=5mA to 1.0A  0.5mAVi=7V to 25V  0.8mAOutput Voltage Drift△Vo/△Tlo=5mA -1.1 mV/℃Output Noise VoltageENf=10Hz to 100KHzTj=25℃  40μV/VoRipple Rejection RatioSVRf=120Hz,Vi=8V to 18V62  dBVoltage DifferentialVdlo=1.0ATj=25℃ 2.0 VOutput ImpedanceRof=1KHz 17 mΩShort-circuit CurrentIscVi=35VTj=25℃ 750 mAPeak CurrentIscpTj=25℃ 2.2 AIf you want to make a 5V power supply with a 7805, output currents up to 1A can be drawn from the IC provided that there is a proper heat sink. A 9V transformer steps down the main voltage, 1A bridge rectifies it and capacitor C1 filters it and 7805 regulates it to produce a steady 5V DC. Then you can test it, turn on the DC power supply and adjust the output voltage of about 8V or slightly larger. Or alternatively you can use a battery 9V-12V as voltage source. Look at the voltmeter panel when you set the voltage. Prepare a DC voltmeter readings on voltage range 50V to measure the output voltage of the IC 7805. Frequently Asked Questions about Voltage Regulator1. What is voltage regulator and how it works?A voltage regulator generates a fixed output voltage of a preset magnitude that remains constant regardless of changes to its input voltage or load conditions. ... A switching regulator converts the dc input voltage to a switched voltage applied to a power MOSFET or BJT switch. 2. What is a voltage regulator used for?Voltage regulator, any electrical or electronic device that maintains the voltage of a power source within acceptable limits. The voltage regulator is needed to keep voltages within the prescribed range that can be tolerated by the electrical equipment using that voltage. 3. What are the three 3 basic types of voltage regulators?There are three types of Switching voltage regulators: Step up, Step down, and Inverter voltage regulators. 4. What happens when voltage regulator goes bad?If you have a bad regulator, it may cause many components such as the fuel pump, ignition system, or other parts which require a minimum amount of voltage to not function correctly. You may experience the engine sputtering, a rough idle, or simply a lack of acceleration when you need it. 5. Where are voltage regulators used?Electronic voltage regulators are found in devices such as computer power supplies where they stabilize the DC voltages used by the processor and other elements. In automobile alternators and central power station generator plants, voltage regulators control the output of the plant.