The Kynix Blog

IntroductionWhat is the IC package? To put it simply, chip packaging is the process of placing a bare integrated circuit chip produced in a foundry on a load-bearing substrate, leading the pins out, and then fixing the package as a whole. It is analogous to the chip's shell, which can wrap, fix, and seal the chip to protect it from external forces such as water, air, moisture, chemicals, and so on.With the continuous improvement of IC packaging, there are more and more types of IC packaging. Various IC packaging packages types, names, logos, etc. can sometimes be confusing. This blog will give you a brief introduction to IC packaging related content, which mainly includes the following three parts: common IC brand identification, IC package terminology, classification of IC packaging, and hope to help you further effectively distinguish and understand IC packaging. Catalog IntroductionEvolution of IC Packaging TypeIC Packaging Types10 Common IC Brand Identification71 kinds of IC package terminology   explainedFAQ Evolution of IC Packaging TypeIn the early stage of the development of chip packaging, there are mainly two types: 1. Through-hole package2. Surface mount packageThrough hole package mainly includes Dual In-line Package (DIP), Transistor Outline (TO), Pin Grid Array (PGA) and so on. Through-hole packageSurface mount package includes TO-252 (D-PAK), Small-Outline Transistor (SOT), Small Outline Package (SOP), Plastic Quad Flat Package (QFP), Plastic Leaded Chip Carrier (PLCC) and so on.Surface mount packageDue to the increasing demand of the surface mount market, the earlier through-hole TO packaging has also begun to develop to the surface mount mode. For example, DPAK packaging, which is easy for many people to confuse, actually refers to TO-252, D2PAK refers to TO-263 and D3PAK refers to TO-268.In the middle and later stage, chip packaging began to enter the era of area array packaging. During this period, packaging types such as Ball Grid Array Package (BGA), Chip Scale Package (CSP), Quad Flat No-lead Package (QFN) and Multi-Chip Module (MCM) began to become popular.With the further development of packaging technology, some chips have begun to adopt the latest three-dimensional stacking packaging technology. IIC Packaging TypesAccording to the different port direction, the common IC packages can be divided into four categories: unilateral, bilateral, four-sided and matrix and several types can be subdivided from the above four categories according to different packaging forms and port shapes. Please refer to the following table for details. IC packaging types In addition, according to the material medium, IC packaging can also be divided into metal, ceramic, plastic and other types, generally distinguished by prefix. For example, "C" refers to ceramic package, "H" refers to package with heat sink and "P" refers to plastic package. 10 Common IC Brand IdentificationMany integrated circuit models’ prefix is often the abbreviation of the manufacturer's name. If you see the following prefix model, you might as well check the corresponding brand first. Of course, this method is not entirely feasible. So you still have to refer to the PDF file of the specific product according to the actual situation.1. AMDThose prefixed with AM are all AMD products, and there are also some confusion between the prefix PAL, CYPRESS and TI. The specific situation should be determined by checking the information.2. ATMELThose prefixed with AT are ATMEL products.3. CYPRESSThose prefixed with CY are all CYPRESS products, and some of them are confused with prefix PALC, PALCE and TI.4. NSCThose prefixed with DM, LF, LM, DS, etc., are basically NSC products. NSC has many product series with other prefix, but the specific situation should be determined by checking the information.5. AD：Those prefixed with AD, OP are AD brand. AD has many other series, such as prefix: DAC, ADG, ADSP and many other series.6. INTERSIL：Those prefixed with HI1, HI2, HI3, HI4, HA1, HA2, HA3, HA4, CA, ICL, ICM, ID, IS, etc., are INTERSIL products. There is also some confusion between prefix MD and INTEL.7. IDT：The prefix for IDT products is almost the prefix IDT.8. MAXThe prefix for MAX products is almost the prefix MAX.9. AGILENTCommon prefixes are HCPL, HDSP, HSSR, and so on.10. ALTERAThe prefix for ALTERA products is almost the prefix for EPM. IC package Figure (105 kinds in total)71 kinds of IC package terminology explainedStill not sure what some IC packaging terms mean exactly? Here is a list of 71 common IC packaging terms for you.1. BGA (Ball Grid Array)BGA is one of the surface mount packages. Spherical bumps are made on the back of the printed substrate to replace pins. LSI chips are assembled on the front of the printed substrate, and then sealed by molding resin or filling method. It is also known as Pad Array Carrier (PAC) and the number of pins can exceed 200. It is a kind of package for multi-pin LSI.The package was developed by Motorola and was first used in portable phones and other devices. 2. BQFP (Quad Flat Package with Bumper)BQFP is one of the QFP packages that is provided with protrusions (cushions) at the four corners of the package body to prevent bending deformation of the pins during transportation. American semiconductor manufacturers mainly use this package in microprocessors and Asic circuits. The center distance of the pin is 0.635 mm, and the number of pins ranges from 84 to 196. (see QFP). 3. Butt Joint PGA (Butt Joint Pin Grid Array)Butt Joint PGA is an alias for surface mount PGA (see Surface Mount PGA) 4. C- (Ceramic)C- is a mark that represents a ceramic package and is often used in practice. For example, CDIP represents Ceramic DIP. 5. CerdipThe Ceramic Dual In-line Package sealed with glass is for circuits such as ECL RAM, DSP (Digital Signal Processor). Cerdip with glass window is used for ultraviolet erasing EPROM and microcomputer circuit with EPROM. The center distance of the pin is 2.54 mm, and the number of pins ranges from 8 to 42. In Japan, this package is represented as DIP-G (G means glass seal). 6. CerquadOne of the surface mount packages, that is, the lower sealed Ceramic QFP, is used to package logic LSI circuits such as DSP. Cerquad with windows is used to package EPROM circuits. The heat dissipation is better than that of Plastic QFP, and power ranges from 1.5 to 2W can be allowed under natural air cooling conditions. But the cost of packaging is 3 to 5 times higher than that of Plastic QFP. Pin center distance has 1.27 mm, 0.8 mm, 0.65 mm, 0.5 mm, 0.4 mm and other specifications. The number of pins ranges from 32 to 368. 7. CLCC (Ceramic Leaded Chip Carrier)Ceramic Leaded Chip Carrier is one of the surface mount packages, and the pins are drawn from the four sides of the package in T-shaped. Those with windows are used for packaging ultraviolet erasing EPROM and microcomputer circuit with EPROM, etc. This packaging is also known as QFJ and QFJ-G (see QFJ). 8. COB (Chip on Board)Chip on Board package is one of the bare chip mounting technologies. The semiconductor chip is connected and mounted on the printed circuit board, the electrical connection between the chip and the substrate is realized by the lead stitching method. Next, cover it with resin to ensure its reliability. Although COB is the simplest bare chip mounting technology, its packaging density is far lower than that of TAB and reverse chip welding technology. 9. DFP (Dual Flat Package)Dual Flat Package is another name for SOP (see SOP). This was once called in the past, but now it is basically out of use.10. DIC (Dual In-line Ceramic Package)This is another name for Ceramic DIP (including glass seal) (see DIP). 11. DIL (Dual In-Line)DIL is an alias for DIP (see DIP). European semiconductor manufacturers often use this name. 12. DIP (Dual In-line Package)Dual In-line Package is one of the through hole packages. The pins are drawn from both sides of the package, and the packaging materials are plastic and ceramic. DIP is the most popular through-hole package, including standard logic IC, memory LSI, microcomputer circuit and so on. The center distance of the pin is 2.54 mm, and the number of pins ranges from 6 to 64. The packaging width is usually 15.2 mm. Some refer to packages with widths of 7.52 mm and 10.16 mm as skinny DIP and slim DIP (narrow DIP, respectively). In most cases, however, it is indistinguishable and is simply collectively referred to as DIP. In addition, Ceramic DIP sealed with low melting point glass is also known as Cerdip (see Cerdip). 13. DSO (Dual Small Out-lint)DSO is the alias for SOP (see SOP). Some semiconductor manufacturers use this name. 14. DICP (Dual Tape Carrier Package)DICP is one of the TCP (loaded packages). The pins are made on the insulation tape and drawn from both sides of the package. Due to the use of TAB (Tape Automated Bonding) technology, the package shape is very thin. It is commonly used in liquid crystal display drive LSI, but most of them are customized products. In addition, the 0.5 mm thick memory LSI thin package is in the development stage. In Japan, DICP is named DTP according to the standard of EIAJ (Japanese Electronic Machinery Industry). 15. DIP (Dual Tape Carrier Package)As we mentioned above, it is the name of DTCP in the standard of the Japanese Electronic Machinery Industry Association. (see DTCP). 16. FP (Flat Package)FP is one of the surface mount packages and it is another name of QFP or SOP (see QFP and SOP). Some semiconductor manufacturers use this name.17. Flip-chipFlip-chip is one of the bare chip packaging technologies. The metal bump is made in the electrode region of the LSI chip, and then the metal bump is connected to the electrode area on the printed substrate by pressure welding. The occupied area of packaging is basically the same as the size of the chip, which is the smallest and thinnest of all packaging technologies. 18. FQFP (fine pitch quad flat package)FQFP usually refers to the QFP which the center distance of the pin is less than 0.65 mm (see QFP). Some conductor manufacturers use this name.19. CPAC (Globe Top PAD Array Carrier)CPAC is another name for BGA by Motorola in the United States. 20. CQFP (Quad Fiat Package with Guard Ring)CQFP is one of the plastic QFP. The pins are masked with a resin protective ring to prevent bending deformation. Before assembling the LSI on the printed substrate, we need to cut off the pin from the protective ring and make it become L-shaped. This package has been mass produced by Motorola in the United States. The center distance of the pin is 0.5 mm, and the maximum number of pins is about 208.21. H- (with heat sink)H- represents a mark with a heat sink. For example, HSOP represents a SOP with a heat sink.22. Pin Grid Array (surface mount type)PGA is usually a through-hole package with a pin length of about 3.4 mm. The surface mount PGA has display–shaped pins on the bottom of the package, ranging in length from 1.5 mm to 2.0 mm. Mounting uses the method of butt joint with the printed substrate, so it is also known as butt joint PGA. Because the center distance of the pin is only 1.27 mm, which is half smaller than the through-hole PGA, the package body cannot be made very large, and the number of pins is more than the through-hole type (ranges from 250 to 528). It is a package for large-scale logical LSI. The packaging substrate has a multi-layer ceramic substrate and a glass epoxy resin printing base. Packaging based on multi-layer ceramic substrate has been practical. 23. JLCC (J-Leaded Chip Carrier)JLCC refers to the alias for windowed CLCC and windowed Ceramic QFJ (see CLCC and QFJ). The name used by some semiconductor manufacturers. 24. LCC (Leadless chip carrier)LCC refers to a surface mount package with only electrode contact and no pin on the four sides of the ceramic substrate. It is a high-speed and high-frequency IC package, also known as Ceramic QFN or QFN-C (see QFN). 25. LGA (Land Grid Array)LGA , that is, an array state flat electrode contact package made on the bottom surface. All we need to do is to insert the socket when assembling. Ceramic LGA, with 227 contacts (1.27 mm center distance) and 447 contacts (2.54 mm center distance) has been used in high speed logic LSI circuits. LGA can accommodate more input and output pins in a smaller package than QFP. In addition, because of the small impedance of the lead, it is very suitable for high-speed LSI. However, due to the complexity of socket production and high cost, it is basically not used much now. But the demand for it is expected to increase in the future. 26. LOC (Lead on Chip)LOC is one of the LSI packaging technologies. The front end of the lead frame is located at the top of the chip. A convex solder joint is made near the center of the chip, and the lead is stitched for electrical connection. Compared with the original structure in which the lead frame is arranged near the side of the chip, the chip contained in the package of the same size is up to about 1 mm wide. 27. LQFP (Low Profile Quad Flat Package)LQFP is a kind of QFP whose package body thickness is 1.4 mm and this is the name used by the Japanese Electronics and Machinery Industry according to the new QFP shape specification. 28. L-QUADL-QUAD is one of the Ceramic QFP. The thermal conductivity of aluminum nitride for packaging substrate is 7 to 8 times higher than that of alumina and has good heat dissipation. The frame of the package is sealed with alumina and the chip is sealed by filling method, thus the cost is suppressed. It is a package developed for logical LSI that allows 3 w power under natural air cooling conditions. LSI logic packages with 208 pins (0.5 mm center distance) and 160 pins (0.65 mm center distance) have been developed and put into mass production in October 1993. 29. MCM (Multi-Chip Module)MCM is a package that assembles multiple bare semiconductor chips on a wiring substrate. According to the substrate materials, it can be divided into MCM-L, MCM-C and MCM-D. MCM-L is a module that uses the usual glass epoxy resin multi-layer printed substrate. The wiring density is not that high and the cost is low. MCM-C is a module which uses thick film technology to form multi-layer wiring and uses ceramics (alumina or glass-ceramic) as substrate, which is similar to mixing IC with thick film of multi-layer ceramic substrate. There is no significant difference between them, and the wiring density was higher than that of MCM-L.MCM-D is a module which uses thin film technology to form multi-layer wiring and uses ceramics (alumina or aluminum nitride) or Si and Al as substrate. The wiring density is the highest of the three modules, but the cost is also high. 30. MFP (Mini Flat Package)MFP is another name for plastic SOP or SSOP (see SOP and SSOP) and it is used by some semiconductor manufacturers. 31. MQFP (Metric Quad Flat Package)MQFP is a classification of QFP according to the JEDEC standard. It refers to standard QFP with a pin center distance of 0.65 mm and a body thickness of 3.8 mm~2.0 mm (see QFP). 32. MQUAD (Metal Quad)MQUAD is a kind of QFP package developed by Olin Company in the United States. The substrate and cover are made of aluminum and sealed with adhesive. The power of 2.5 w~2.8 w can be allowed under the condition of natural air cooling. SHINKO ELECTRIC INDUSTRIES CO., LTD. was licensed to start production in 1993. 33. MSP (Mini Square Package)MSP is another name for QFI (see QFI) and is often called in the early days of development. QFI is the name specified by the Electronic Machinery Industry Association of Japan. 34. OPMAC (Over Molded Pad Array Carrier)OPMAC is the name used by Motorola for molded resin seal BGA (see BGA). 35. P- (plastic)P- is the mark that represents a plastic package. For example, PDIP represents Plastic DIP. 36. PAC (Pad Array Carrier)PAC is an alias for BGA (see BGA). 37. PCLP (Printed Circuit Board Leadless Package)Fujitsu of Japan uses the name for Plastic QFN (Plastic LCC) (see QFN). The center distance of the pin can be divided into two specifications: 0.55 mm and 0.4 mm. It is currently in the development phase. 38. PFPF (Plastic Flat Package)PFPF is an alias for Plastic QFP (see QFP) and it is used by some LSI manufacturers. 39. PGA (Pin Grid Array)PGA is one of the through-hole packages, and the vertical pins on the bottom are arranged in the form of display. The packaging substrate is basically multi-layer ceramic substrate. In the case of not specifically indicating the name of the material, most of the Ceramic PGA, are used in high-speed and large-scale logic LSI circuits. The cost is high. The center distance of the pin is usually 2.54 mm, and the number of pins ranges from 64 to 447. In order to reduce the cost, the packaging substrate can be replaced by glass epoxy resin printing substrate. There is also Plastic PGA with 64 to 256 pins. In addition, there is a short pin surface mount PGA (Butt Joint PGA) with a pin center distance of 1.27 mm. (see Surface Mount PGA). 40. Piggy BackIt refers to a ceramic package with sockets and its shape is similar to that of DIP, QFP and QFN. It is used to confirm operation on the evaluation program when developing a device with a microcomputer. For example, plug the EPROM into the socket for debugging. This kind of package is basically custom-made, and there is little circulation on the market. 41. PLCC (Plastic Leaded Chip Carrier)PLCC is one of the surface mount packages. The pin is drawn from the four sides of the package in the shape of T and is made of plastic. Texas Instruments was first used in 64k-bit DRAM and 256k-bit DRAM, and now it has been widely used in logic LSI, DLD (or logic device) and other circuits. The center distance of the pin is 1.27 mm, and the number of pins ranges from 18 to 84. The J-shaped pin is not easy to deform and is easier to operate than QFP, but the appearance inspection after welding is more difficult.PLCC is similar to LCC (also known as QFN). In the past, the only difference between the two was that the former used plastic and the latter used ceramics. But now there are J-shaped pin packages made of ceramics and pin-free packages made of plastic. (marked as plastic LCC, PC LP, P-LCC, etc.) Thus they have been unable to distinguish.To this end, the Japanese Electronics and Machinery Industry decided in 1988 to refer to packages with J-shaped pins on four sides as QFJ, and packages with electrode bumps on four sides as QFN (see QFJ and QFN). 42. P-LCC (Plastic Leadless Chip Carrier)Sometimes it is another name for Plastic QFJ, sometimes it is another name for QFN (Plastic LCC) (see QFJ and QFN). Some LSI manufacturers use PLCC for lead package and P-LCC for lead-free package to show the difference. 43. QFH (Quad Flat High Package)QFH is a kind of Plastic QFP. In order to prevent the package body from breaking, the QFP body is made thicker (see QFP). This is the name used by some semiconductor manufacturers. 44. QFI (Quad Flat I-leaded Package)QFI is one of the surface mount packages. The pin is drawn from the four sides of the package in I-shaped. It is also known as MSP (see MSP). The mount is connected with the printed substrate by butt joint. Because there is no protruding part of the pin, the occupied area of the mount is smaller than that of QFP. Hitachi has developed and used this package for video analog IC. In addition, this package is also used by PLL IC of Motorola, a Japanese company. The center distance of the pin is 1.27 mm, and the number of pins is from 18 to 68.45. QFJ (Quad Flat J-leaded Package)QFJ is one of the surface mount packages. The pin is drawn from the four sides of the package in the shape of J. It is the name stipulated by the Japan Electronic Machinery Industry Association. The center distance of the pin is 1.27 mm. There are two kinds of materials: plastic and ceramics. Plastic QFJ is mostly called PLCC (see PLCC), and it is for microcomputers, gate displays, DRAM, ASSP, OTP, etc. The number of pins ranges from 18 to 84. Ceramic QFJ is also known as CLCC and JLCC (see CLCC). The windowed package is used for ultraviolet erasing EPROM and microcomputer chip circuits with EPROM. The number of pins ranges from 32 to 84.46. QFN (Quad Flat Non-leaded Package)QFN is one of the surface mount packages and it is often called LCC now. QFN is the name specified by the Electronic Machinery Industry Association of Japan. The four sides of the package are equipped with electrode contacts. Because there are no pins, the mounting area is smaller than QFP, and the height is lower than QFP. However, when there is a stress between the printed substrate and the package, it cannot be alleviated at the electrode contact. Therefore, it is difficult for electrode contacts to make as many pins as QFP. The number of pins is generally ranges from 14 to 100.There are two kinds of materials: ceramic and plastic. When marked with LCC, they are basically Ceramic QFN. The center of the electrode contact is 1.27 mm.Plastic QFN is a low-cost package for printing substrate with glass epoxy resin. In addition to 1.27 mm, there are two kinds of electrode contact center distance: 0.65 mm and 0.5 mm. This package is also known as Plastic LCC, PCLC, P-LCC and so on.47. QFP (Quad Flat Package)QFP is one of the surface mount packages, with pins drawn from four sides in L-shaped. There are three kinds of substrate: ceramic, metal and plastic. In terms of quantity, plastic packaging accounts for the vast majority. When the material is not specifically indicated, most of the cases are Plastic QFP. Plastic QFP is the most popular multi-pin LSI package. It is not only used in microprocessor, gate display and other digital logic LSI circuits, but also in VTR signal processing, audio signal processing and other analog LSI circuits. The center distance of pin has 1.0 mm, 0.8 mm, 0.65 mm, 0.5 mm, 0.4 mm, 0.3 mm and other specifications. The maximum number of pins in the 0.65 mm center distance specification is 304.In Japan, QFP with a pin center distance less than 0.65 mm is called QFP (FP). But now the Japanese Electronics and Machinery Industry will re-evaluate the shape of the QFP. There is no difference in the center distance of the pin. But according to the thickness of the package body, it can be divided into three types: QFP (2.0 mm~3.6 mm thickness), LQFP (1.4 mm thickness) and TQFP (1.0 mm thickness).In addition, some LSI manufacturers specifically refer to the QFP with the pin center distance as 0.5 mm as shrink QFP or SQFP, VQFP.However, some manufacturers also call the QFP with pin center distance of 0.65 mm and 0.4 mm SQFP, which makes the name a little confused. The disadvantage of QFP is that when the center distance of the pin is less than 0.65 mm, the pin is easy to bend. In order to prevent pin deformation, several improved QFP varieties have emerged such as BQFP with tree finger buffer pads on the four corners of the package (see BQFP); GQFP with a resin protection ring which covers the front of the pin (see GQFP) and TPQFP (see TPQFP)，which is set test bumps in the package body and can be tested in a special fixture to prevent pin deformation.In the aspect of logical LSI, many development products and highly reliable products are packaged in multi-layer ceramic QFP. Products with a minimum pin center distance of 0.4 mm and a maximum number of pins of 348 have also been introduced. In addition, there are glass-sealed ceramic QFP.48. QFP (FP) (QFP fine pitch)This is the name specified in the standard of the Japan Electronic Machinery Industry Association. The pin center distance is 0.55 mm, 0.4 mm, 0.3 mm and so on, which is smaller than that of 0.65 mm (see QFP).49. QIC (Quad In-line Ceramic Package)QIC is another name for Ceramic QFP and it is used by some semiconductor manufacturers (see QFP, Cerquad).50. QIP (Quad In-line Plastic Package)QIP is another name for Ceramic QFP and is used by some semiconductor manufacturers (see QFP, Cerquad).51. QTCP (Quad Tape Carrier Package)QTCP is one of the TCP packages that forms pins on the insulation tape and leads out from the four sides of the package. It is a thin package using TAB technology (see TAB, TCP).52. QTP (Quad Tape Carrier Package)QTP is the name used by the Japanese Electronic Machinery Industry for the shape specifications developed by QTCP in April 1993 (see TCP).53. QUIL (Quad In-Line)QUIL is an alias for QUIP (see QUIP).54. QUIP (Quad In-line Package)The pin is drawn from both sides of the package and bends down into four columns at every other pin. The pin center distance is 1.27 mm. When inserted into the printed substrate, the insertion center distance becomes 2.5 mm. Therefore, it can be used for standard printed circuit boards.It is smaller package than the standard DIP. Nippon Electric has adopted this kind of package in microcomputer chips for desktop computers and household appliances. There are two kinds of materials: ceramics and plastics. The number of pins is 64. 55. SDIP (Shrink Dual In-line Package)SDIP is one of the through-hole packages with the same shape as the DIP. Its pin center distance (1.778 mm) is less than DIP (2.54 mm) so it gets this name. The number of pins ranges from 14 to 90. It is also known as SH-DIP. There are two kinds of materials: ceramics and plastics.56. SH-DIP (Shrink Dual In-line Package)SH-DIP is the same as SDIP and it is used by some semiconductor manufacturers. 57. SIL (Single In-Line)SIL is an alias for SIP (see SIP). European semiconductor manufacturers often use this name. 58. SIMM (Single In-line Memory Module)A memory module provided with electrodes only near one side of the printed substrate. It usually refers to a module inserted into a socket. The standard SIMM has two specifications: 30 electrodes with center distance of 2.54 mm and 72 electrodes with center distance of 1.27 mm. The SIMM with 1 megabit and 4 megabit DRAM packaged with SOJ on one or both sides of the printed substrate has been widely used in personal computers, workstations and other devices. There are at least 30 to 40 percent of DRAM is installed in SIMM. 59. SIP (Single In-line Package)The pins are drawn from one side of the package and arranged in a straight line. The package is laterally mounted on the printed substrate. The center distance of the pin is usually 2.54 mm, and the number of pins ranges from 2 to 23, most of which are customized products. Packages come in different shapes. Sometimes packages with the same shape as ZIP are called SIP.60. SK-DIP (Skinny Dual In-line Package)SK-DIP is a kind of DIP which has a narrow body with a width of 7.62 mm and a pin center distance of 2.54 mm. It is often collectively referred to as DIP (see DIP).61. SL-DIP (Slim Dual In-line Package)SL-DIP is a kind of DIP which has a narrow body with a width of 10.16 mm and a pin center distance of 2.54 mm. It is commonly referred to as DIP. 62. SMD (Surface Mount Devices)Occasionally, some semiconductor manufacturers classify SOP as SMD (see SOP).63. SO (Small Out-line)SO is another name for SOP and is used by many semiconductor manufacturers in the world. (see SOP).64. SOI (Small Out-line I-leaded Package)SOI is one of the surface mount packages. The pin is drawn down from both sides of the package in I-shaped, with a center distance from 1.27 mm and 26 pins. The occupied area of mounting is smaller than that of SOP. Hitachi uses this package in analog IC (IC for motor drive).65. SOIC (Small Out-line Integrated Circuit)SOIC is an alias for SOP (see SOP). Many semiconductor manufacturers abroad use this name.66. SOJ (Small Out-Line J-Leaded Package)SOJ is one of the surface mount packages. The pin is J-shaped from both sides of the package, so it gets its name. They are usually plastic products and are used in memory LSI circuits such as DRAM and SRAM. But most of them are used in DRAM.Many of the DRAM devices packaged in SOJ are mounted on SIMM. The center distance of the pin is 1.27 mm, and the number of pins ranges from 20 to 40 (see SIMM).67. SOL (Small Out-Line L-leaded Package)The name used for SOP in accordance with the JEDEC standard (see SOP).68. SONF (Small Out-Line Non-Fin)SONF is the SOP without heat sink. As the same as the usual SOP, the NF (non-fin) mark is intentionally added In order to show that there is no heat sink in the power IC package. The name is used by some semiconductor manufacturers (see SOP).69. SOF (Small Out-Line Package)SOF is one of the surface mount packages with pins drawn from both sides of the package in L-shaped. There are two kinds of materials: plastic and ceramics. And it is also known as SOL and DFP.SOP is not only used for memory LSI, but also widely used in small-scale ASSP and other circuits. SOP is the most popular surface mount package in areas where the input and output terminals do not exceed 10 to 40. The center distance of the pin is 1.27 mm, and the number of pins is from 8 to 44.In addition, a SOP with a pin center distance less than 1.27 mm is also known as a SSOP. A SOP with assembly height less than 1.27 mm is called TSOP (see SSOP, TSOP). There is also a SOP with a heat sink. 70. SOW [Small Outline Package(Wide-Type)]SOW refers to wide body SOP and this name is used by some semiconductor manufacturers.71. COG (Chip on Glass)COG (Chip on Glass) packaging technology, which has great influence on the development of Liquid Crystal Display (LCD) technology, is becoming more and more practical in the world.FAQ 1. What is package in IC?The case, known as a "package", supports the electrical contacts which connect the device to a circuit board. In the integrated circuit industry, the process is often referred to as packaging. Other names include semiconductor device assembly, assembly, encapsulation or sealing.2. What are the different types of IC packages?What is IC packaging?DIP (Double In-line Package)SOP/SOIC/SO (Small Outline Package)QFP (Quad Flat Package)QFN/LCC (Quad Flat Non-leaded Package)BGA (Ball Grid Array Package)CSP (Chip Scale Package)3. What is IC and how it works?An integrated circuit, or IC, is small chip that can function as an amplifier, oscillator, timer, microprocessor, or even computer memory. An IC is a small wafer, usually made of silicon, that can hold anywhere from hundreds to millions of transistors, resistors, and capacitors.4. What are the types of ICs?Below is the classification of different types of ICs basis on their chip size.SSI: Small scale integration. 3 – 30 gates per chip.MSI: Medium scale integration. 30 – 300 gates per chip.LSI: Large scale integration. 300 – 3,000 gates per chip.VLSI: Very large scale integration. More than 3,000 gates per chip.5. How do I know my IC type?How to Identify Integrated Circuit ChipsIdentify the manufacturer first. ...Look up data sheets in the manufacturer's printed catalog. ...Look up a part number in an electronic retailer's catalog. ...Use the technical specifications for a piece of equipment to find part numbers and alternates.6. What is the most common type of digital IC package?DIP (Dual in-line packages)DIP, short for dual in-line package, is the most common through-hole IC package you'll encounter. These little chips have two parallel rows of pins extending perpendicularly out of a rectangular, black, plastic housing.7. What are the advantages of IC?The advantages of ICs : (i) Extremely small in size, (ii) Low power consumption, (iii) Reliability, (iv) Reduced cost, (v) Very small weight and (vi) Easy replacement. 8. What is the IC package?What Is the Package in IC? IC packaging refers to the material that contains a semiconductor device. The package is a case that surrounds the circuit material to protect it from corrosion or physical damage and allow mounting of the electrical contacts connecting it to the printed circuit board (PCB). 9.Why IC packaging is important?IC packaging is the ability to provide more and more I/O interconnections to a die (bare chip) that is increasingly shrinking in size is an ever-present problem.10. What are the three basic types of linear IC packages?IC packages can be grouped into three general categories; Dual In-line Packages, Chip Carriers and Grid Arrays. All the packages, regardless of the category has a body style that scales with pin count.

Introduction Everyone has heard of FPGA more or less, such as Bitcoin mining, or Microsoft said before that it will use FPGA instead of CPU in the data center. So what exactly is it? Why use it? Compared with CPU, GPU, and ASIC, what are the characteristics of FPGA? FPGA is a chip that can reconfigure circuits and is a hardware reconfigurable architecture. Through programming, users can change its application scenarios at any time, and it can simulate various parallel operations of hardware such as CPU and GPU. By interconnecting with the high-speed interface of the target hardware, the FPGA can complete the low-efficiency part of the target hardware, thereby achieving acceleration at the system level. What Is an FPGA? Catalog Introduction Ⅰ FPGA vs CPU vs GPU vs ASIC Ⅱ Five Advantages of FPGA 2.1 Performance 2.2 Time-to-Market 2.3 Cost 2.4 Stability 2.5 Long-Term Maintenance Ⅲ New Applications of FPGA Ⅳ Development Trend of FPGA Ⅴ FAQ Ⅰ FPGA vs CPU vs GPU vs ASIC The core difference between FPGA and CPU, GPU, ASIC chips, etc. is that the connection and logic layout of the underlying operation unit are not solidified. Users can program the logic unit and switch array through EDA software to configure the function, so as to realize the integration of specific functions.FPGA appears as a semi-custom circuit in the field of application-specific integrated circuits (ASIC), which not only solves the shortcomings of custom circuits, but also improves the limited number of original programmable device gate circuits. Compared with ASIC chips, an important feature of FPGA is its programmable characteristics, that is, the user can specify the FPGA to realize a specific digital circuit through the program. Furthermore, FPGA chips are one of the best choices for small batch systems to improve system integration and reliability. Figure 1. FPGA Basic Structure So why is FPGA so fast? This is all because the computer's CPU(central processing unit) and GPU(graphics processing unit) belong to the von Neumann structure, with instruction decoding and execution, and shared memory. FPGAs, on the other hand, are instruction-free and memory-free architectures that make FPGA chips much more energy-efficient than CPUs or even GPUs. Figure 2. Von Neumann Structure In the von Neumann architecture, since the execution unit (such as the CPU core) may execute any instruction, so an instruction memory, a decoder, an operator of various instructions, and branch and jump processing logic are required. Due to the complex control logic of the instruction stream, it is impossible to have too many independent instruction streams. Therefore, the GPU uses SIMD (single instruction, multiple data) to allow multiple execution units to process different data at the same pace, and the CPU also supports SIMD instruction. The function of each logic unit of the FPGA has been determined during reprogramming, and no instructions are required. Figure 3. Computer CPU If the GPU is used for acceleration, in order to fully utilize the GPU computing, the batch size cannot be too small, and the delay will be on the order of milliseconds. Using FPGA to accelerate, only microsecond-level PCle delay is required. Why is FPGA so much lower latency than GPU? This is basically an architectural difference. FPGAs have both pipeline parallelism and data parallelism, while GPUs have almost only data parallelism (with limited pipeline depth).For example, FPGA chips can change the running hardware design on the chip every few seconds, while chips such as CPU and ASIC are already solidified when they leave the factory and cannot be changed. If ASIC, CPU, GPU, etc. are built buildings, and the routes of rooms, corridors, and stairs in the building have been fixed, while the interior of FPGA is similar to the magic staircase in Hogwarts, which can change the route of room to room at any time. In addition, FPGA does not need to compile the instruction system at the software application level like CPU and GPU. To program FPGA, use hardware description language, and directly compile and burn it into a combination of transistor circuits, that is, directly use transistor circuits to implement user algorithms.The biggest feature of FPGA is its flexibility. It can realize any digital circuit you want and can customize various circuits. Reduce the shackles of special chips, truly tailor-made for your own products, you can flexibly change the design during the design process, and have field programmability, so it is especially suitable for applications that require continuous changes in physical operation logic, such as AI algorithm optimization, data center applications, etc. Architecture Throughput（int ops） Delay Flexibility CPU ~1T N/A Very High GPU ~10T ~1ms High FPGA(Stratix V) ~1T ~1us High FPGA(Stratix 10) ~10T ~1us High ASIC ~10T ~1us Low The FPGA is set up by the RAM stored on the chip to reset its working state, so the on-chip RAM needs to be programmed when working. Users can use different programming methods according to different configuration modes, which can be said to be very flexible and convenient. The FPGA has the following configuration modes:🔺Parallel Mode: Parallel PROM, Flash configures FPGA.🔺Master-Slave Mode: One PROM configures multiple FPGAs.🔺Serial Mode: Serial PROM configures FPGA.🔺Peripheral Mode: The FPGA is used as a peripheral of the microprocessor and programmed by the microprocessor. Computational performance compared with CPU: For example, Stratix series FPGAs perform integer multiplication operations, and their performance is equivalent to that of a 20-core CPU, and for floating-point multiplication operations, their performance is equivalent to an 8-core CPU.Computational performance compared with GPU: FPGA performs integer multiplication and floating-point multiplication operations. There is an order of magnitude difference in performance compared to GPU. The computing performance of GPU can be approached by configuring multipliers and floating-point operation components. Figure 4. CPU and GPU Architecture Diagram The core advantage of FPGA for performing computation-intensive tasks: tasks such as search engine sorting and image processing have strict requirements on the return time limit of results, and it is necessary to reduce the delay of computing steps. Under the traditional GPU acceleration scheme, the data packet size is large, and the delay can reach the millisecond level. Under the FPGA acceleration scheme, the PCIe latency can be reduced to the microsecond level. Driven by long-term technology, the data transmission delay between CPU and FPGA can be reduced to less than 100 nanoseconds.The FPGA can build the same number of pipelines (pipeline parallel structure) for the number of data packet steps, and the data packets can be output immediately after being processed by multiple pipelines. The GPU data parallel mode relies on different data units to process different data packets, and the data units need to be input and output consistently. For stream computing tasks, the FPGA pipeline parallel structure has a natural advantage in latency. FPGA is used to process communication-intensive tasks and is not limited by network cards. It outperforms CPU solutions in terms of packet throughput and delay, and has strong delay stability. Therefore, FPGAs have obvious advantages over CPUs when performing large data processing tasks with high repetition rates.By programming the FPGA, the user can change the internal connection structure of the chip at any time to realize any logic function. Especially in industries with immature technical standards or rapid development and change, FPGA can effectively help enterprises reduce investment risks and sunk costs, and is a functional and economical choice. Figure 5. Computer GPU With the evolution of intelligent market demand, highly customized chips (ASIC SoC) have led to a sharp increase in market risks due to the large scale of non-repetitive investment and long R&D cycle. Relatively speaking, FPGA has advantages in the field of parallel computing tasks, and can replace some ASICs in the field of high performance and multi-channel. The demand for multi-channel computing tasks in the field of artificial intelligence (AI) drives the evolution of FPGA technology to the mainstream. Figure 6. ASIC SoC Ⅱ Five Advantages of FPGA 2.1 Performance Taking advantage of hardware parallelism, FPGAs break the sequential execution model and complete more processing tasks per clock cycle, surpassing the computing power of digital signal processors (DSPs). BDTI(Big Data Test Infrastructure), a well-known analysis and benchmarking company, has published benchmarks that show that in some applications, FPGAs can handle many times more processing power per dollar than DSP solutions. Controlling input and output (I/O) at the hardware level provides faster response times and specialized functionality to meet application needs. 2.2 Time-to-Market Despite increasing time-to-market constraints, FPGA technology offers flexibility and the ability to rapidly prototype. Users can test an idea or concept and complete verification in hardware without going through the lengthy manufacturing process of custom ASIC design. This allows users to make incremental modifications and iterate FPGA designs in hours, saving weeks. Commercial off-the-shelf (COTS) hardware provides different types of I/O connected to user-programmable FPGA chips. The increasing popularity of high-level software tools reduces the learning curve and abstraction layers, and often provides useful IP cores (pre-built functions) for advanced control and signal processing. 2.3 Cost The non-recurring engineering (NRE) cost of custom ASIC design far exceeds the cost of FPGA-based hardware solutions. The huge initial investment in ASIC design shows that OEMs need to ship thousands of chips each year, but more end users need custom hardware capabilities that enable the development of tens to hundreds of systems. The nature of programmable chips means that users can save on manufacturing costs as well as long lead times for assembly. System requirements change from time to time, but the cost of changing the FPGA design is negligible compared to ASCI's huge expense. 2.4 Stability Software tools provide the programming environment, and FPGA circuits are the real "hard" implementation of programming. Processor-based systems often contain multiple layers of abstraction that can schedule tasks and share resources among multiple processes. The driver layer controls hardware resources, while the operating system manages memory and processor bandwidth. For any given processor core, only one instruction can be executed at a time, and processor-based systems face the risk of tightly time-bound tasks taking over each other at all times. FPGAs, on the other hand, do not use an operating system, and have true parallel execution and deterministic hardware that focuses on each task, reducing the chance of stability issues. 2.5 Long-Term Maintenance As mentioned above, FPGA chips are field-upgradable without the time and expense involved in redesigning ASICs. For example, digital communication protocols contain specifications that can change over time, and ASIC-based interfaces can create maintenance and forward compatibility difficulties. Reconfigurable FPGA chips can accommodate future modifications. As a product or system matures, users can enhance functionality without spending time redesigning hardware or modifying board layouts.   Ⅲ New Applications of FPGA At present, the FPGAs mainly produced by Xilinx and Altera with the highest market share, which are all based on SRAM technology, and need to be connected to an external memory to save the program when in use. When powered on, the FPGA reads the data in the external memory into the on-chip RAM, and after completing the configuration, it enters the working state. When power off, the FPGA returns to a white chip, and the internal logic disappears. In this way, the FPGA can not only be used repeatedly, but also does not require a special programmer, but only a general EPROM and PROM programmer. So Actel, QuickLogic and other companies also provide FPGAs with anti-fuse technology, which can only be downloaded once. They have the advantages of anti-radiation, high & low temperature resistance, low power consumption and fast speed. They are widely used in military and aerospace fields. FPGA cannot be erased and written repeatedly, which is troublesome and expensive in the early stage of development. Lattice is the inventor of ISP technology, which has certain characteristics in small-scale PLD applications. Early Xilinx products generally did not involve military and aerospace markets, but now a number of products such as Q Pro-R have entered such fields.In the industrial field, FPGA chips are widely used in the industrial field, and are widely used in video processing, image processing, CNC machine tools and other fields to realize signal control and operation acceleration functions. With the development of intelligence and automation technology, the industrial field is gradually shifting from human resources as the core element to intelligent unmanned factories with automation as the core element.Smart electric vehicles will be the mainstream development direction of the automotive industry in the future. At present, the application of FPGA in automotive cameras and sensors is relatively mature. In the artificial intelligence system of automatic/intelligent driving vehicles, the applicability of FPGA will be the most suitable for processing sophisticated ADAS and autonomous driving. Figure 7. FPGA for Auto In the field of automotive electronic system interface and control, FPGA chips are used to control and drive electric vehicle motor control systems, connect various in-vehicle equipment such as driving systems, instrument panels, radar, ultrasonic sensors, etc. control. In the field of video bridging and fusion, FPGA chips can be used to realize functions such as signal bridging of multiple image sensors, 3D surround view video fusion, reversing auxiliary video, and assisted driving video.In the field of communication, the number of 5G base stations has increased, and the FPGA usage of a single base station has increased, driving the increase in FPGA demand. According to estimates, the FPGA consumption of a 5G single base station is expected to increase from 1-3 blocks in the 4G period to 4-5 blocks in the 5G period. Figure 8. RFSoC FPGA Board Target 5G eFPGA technology is superior to traditional FPGA solutions in terms of performance, cost, power consumption, profitability, etc., and can provide flexible solutions for different application scenarios and different market segments. The economic trend of increasing design complexity and falling equipment costs has stimulated the market demand for eFPGA technology.   Ⅳ Development Trend of FPGA First of all, with the commercialization of the new generation of communication technology, the demand for products such as communication base stations, servers, and intelligent terminals will further expand, thereby driving the increase in the market demand for FPGA chips. At the same time, smart cities, smart factories, and consumer electronics pay more attention to the functionality of various smart IoT devices, which will drive the wide application of FPGA chips in smart IoT devices. With the development of the Internet of Vehicles technology, the scale of the use of FPGA chips in the automotive industry will increase day by day to build a more complete Internet of Vehicles and realize smarter autonomous driving functions. Therefore, with the rapid penetration of 5G, the vigorous development of AI and the increasing trend of automotive intelligence, it is expected that the demand for FPGAs in the three fields of communication, AI and automotive electronics will continue to increase in the future, which will also promote The FPGA industry continues to grow.   Ⅴ FAQ 1. What is FPGA and why it is used?The acronym FPGA stands for Field Programmable Gate Array. It is an integrated circuit that can be programmed by a user for a specific use after it has been manufactured. ... These blocks create a physical array of logic gates that can be customized to perform specific computing tasks. 2. Is FPGA faster than GPU?The difference between GPU and FPGA performance is not a static factor, but it does depend on the size of the data set. A study by Sanaullah and Herbordt [7] revealed that FPGA can compute small samples of 3D FFT tens of times faster than GPU. The difference is less clear when the data set gets bigger. 3. Is FPGA faster than CPU?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. And as a side benefit, no trace of all this is left on the CPU because it's never touched when an FPGA is used. 4. Are FPGAs efficient?Efficiency and Power: FPGAs are well-known for their power efficiency. A research project done by Microsoft on an image classification project showed that Arria 10 FPGA performs almost 10 times better in power consumption. 5. Is FPGA programming hard?FPGA vendors have touted their wares as ideal replacements for DSPs, CPUs, and GPUs – even for all of them in a single device – but they are notoriously difficult for software engineers to program as they are not anything like a conventional processor. 6. What can you do with FPGAs?Uses for FPGAs cover a wide range of areas—from equipment for video and imaging, to circuitry for computer, auto, aerospace, and military applications, in addition to electronics for specialized processing and more. 7. What is the difference between processor and FPGA?Microprocessor vs FPGA: A microprocessor is a simplified CPU or Central Processing Unit. ... An FPGA doesn't have any hardwired logic blocks because that would defeat the field programmable aspect of it. An FPGA is laid out like a net with each junction containing a switch that the user can make or break. 8. What language is used to program FPGA?VerilogTraditionally, FPGAs are programmed using pro-level hardware-description languages such as Verilog or VHDL. 9. How many times can you program an FPGA?There is effectively no limit to the number of times a device can be reconfigured; the configuration is stored in SRAM, which has no write limit. most Fpgas can be passively loaded from a processor, one word at a time. That processor can get the FPGA image from anywhere. 10. What are the advantages of FPGA?FPGA advantagesLong-term availabilityUpdating and adaptation at the customerVery short time-to-marketFast and efficient systemsAcceleration of softwareReal-time applicationsMassively parallel data processing 11. How do you make an FPGA?FPGA design checklistMake sure you have plenty of time to spare.Find a decent computer.If you can afford it, add a big display.Decide which operating system to use.Consider using a virtual machine (VM).Select an FPGA vendor.Pick out a suitable development board.Select an embedded processor to use. 12. What is FPGA for beginners?FPGA stands for Field Programmable Gate Array. As you may already know, FPGA essentially is a huge array of gates that can be programmed and reconfigured any time anywhere. Huge array of gates is an oversimplified description of FPGA. FPGA is indeed much more complex than a simple array of gates. 13. What is FPGA in Verilog?FPGAs are nothing, but reconfigurable logic blocks and interconnects can be programmed by Hardware Description Language like Verilog/ VHDL to perform a specific functionality. 14. Do we need to program the FPGA once powered off?If you have a SRAM-based FPGA, like the Spartan 3, then you have to program it each time it is powered up. The reason for this is that the SRAM which stores the configuration is volatile and loses the programmed configuration after power is switched off. 15. How is FPGA different from microcontroller?One of the main differences between a microcontroller and an FPGA is that an FPGA doesn't have a fixed hardware structure, while a microcontroller does. While FPGAs include fixed logic cells, these, along with the interconnects, can be programmed in parallel by using HDL coding language.

Today I want to share a project of making a simple automatic street light controller using relay and LDR I found in circuitdigest with you.   You have seen street light which automatically gets turned on in the night and gets turned off in the morning or day time, there are sensors who senses the light and control the light accordingly. These Street lights are an important project in smart cities.   So here in this project, we are going to make a Simple Automatic Street Light Controller Using Relay and LDR. This circuit is very simple circuit and can be built with Transistors and LDR, you don’t need any op-amp or 555 IC to trigger the AC load. Here we have used an AC bulb as street light. Some applications of this circuit are street light controlling, home/office light controlling, day and night indicators, etc.   Components Required:   Transistor BC547 -2 LDR (Light Dependent Resistor) Relay Resistor 1k 100k Potentiometer Power Supply 12v -1 Connecting wires Jumper wires Screw terminal Block 2 pin or 3 pin Bread Board or Perf Board 1n4007 Diode AC supply AC Load or Bulb   Here you may want to know: what is LDR? LDRs are made from semiconductor materials to enable them to have their light sensitive properties. There are many types but one material is popular and it is cadmium sulphide (CdS). These LDRs or PHOTO REISTORS works on the principle of “Photo Conductivity”. Now what this principle says is, whenever light falls on the surface of the LDR (in this case) the conductance of the element increases or in other words the resistance of the LDR falls when the light falls on the surface of the LDR. This property of the decrease in resistance for the LDR is achieved because it is a property of semiconductor material used on the surface. LDR (Light Dependent Resistor)   Circuit Diagram and Explanation:   Below is the circuit diagram of this Light sensing Street Light:       In this project, we have used an LDR (Light Dependent Resistor) which is responsible for detecting light and darkness. The resistance of LDR increases in darkness and reduces in presence of light. This circuit is same as a Dark Detector or Light Detector Circuit, only here we have replaced simple LED with a AC load, using a Relay. Two BC547 NPN transistors are used to drive the relay. Automatic Street Light circuit using LDR and relay   Whenever light falls over LDR its resistance get decreased and transistor Q1 turns ON and collector of this transistor goes LOW, and this makes the second transistor turns OFF due to getting a LOW signal at its base, so relay also remain turned OFF due to second transistor.   Now whenever LDR senses Darkness, mean no light, then transistor Q1 turned ON due to increase in the resistance of LDR which is responsible for voltage drop at the base of Q1. Due to a LOW signal at the Q1 base, Q2 transistor gets a HIGH signal from the collector of Q1 and turns ON the relay. Relay turned ON the AC load that is connected to relay. A 10K pot is also used for setting up the sensitivity of the circuit.   So this is how automatic Street Lights turns on in the night and turn off in the day, and below is the effect pictures. >>>>>                                                       > >>>>   Ref. KY56-BC547A KY32-1N4007  

Warm hints: The word in this article is about 3000 words and  reading time is about 15 minutes.   This paper is mainly about how to learn analog circuit design. An analog circuit is a circuit used to transmit, transform, process, amplify, measure, and display analog signals. Analog signals refer to continuously changing electrical signals. Analog circuit is the basis of the electronic circuit, which mainly includes amplifier circuit, signal processing, and processing circuit, oscillation circuit, modulation and demodulation circuit, and power supply.    Analog circuit   Catalogs   I. What’s the Engineering Thinking in Analog Circuit II. Commonly Used Semiconductor Devices III. Negative Feedback Basic Concepts IV. Operational Amplifier Development V. Conclusion FAQ I. What’s the Engineering Thinking in Analog Circuit   Analog circuit is a very important profession, and difficult for people to learn. Now, let me talk about my understanding of the analog circuit. When it comes to the understanding and application of analog circuits, I’ve done some projects and participated in competitions. The analog circuit is an engineering course, and the earning focus is to master the engineering ideas. It’s better to put it into practice, instead of only doing the exams. What is the engineering idea? Encyclopedia +explains as this: "Engineering is the application of science and mathematics. Through this, natural material and energy characteristics can be made into efficient, reliable, and human-friendly products flow through a variety of structures, machines, products, systems, and processes, with the shortest Time, and less refined manpower, so the concept of engineering comes out and it has evolved into an independent discipline and skill. "For example, in analog circuits, there is a very Important engineering thinking - approximation.   In high school physics class, we learn a lot of circuits are ideal circuits. The wire resistance is always 0, the transformer efficiency is 100%, the ideal voltmeter resistance is infinite, the ideal ammeter resistance is 0, and so on. You can see that many times the calculation in an analog circuit will often omit one or two smaller items and use the equal sign instead of the equal sign directly.   Why use an approximation? To put it plainly, people’s understanding of nature in human science is not comprehensive enough to describe the natural phenomenon with absolute precision. Or human’s understanding is limited. By the means of approximation, people have not only achieved an obvious effect on solving the problem but also greatly simplifies the procedure and saves time and effort. With this thought, many achievements have been made in human science, which has also proved its reliability.    Summary Mold itself is a very complex subject, and the molding course is just one of the most basic things. Analog Circuit Meaning is the electronic circuit that processes analog signals. Most of the signals in nature are analog signals, and they have continuous amplitude values, such as the sound signal when speaking. Analog circuits can be such signal processing (of course, need to be converted into electrical signals), such as amplifier to amplify the sound signal, the radio can send analog sound signals, image signals. It can even be assumed that all circuits are based on analog circuits (even for digital circuits, the underlying principle is based on analog circuits). Its importance is self-evident.    Due to the rapid development of digital circuits and programmable devices, many superior features are demonstrated. Many electronic devices are slowly digital but still can not do without analog circuits. The most important analog circuit devices, non-semiconductor devices are none other than. The most basic and commonly used semiconductor devices are diodes, transistors, FETs, and operational amplifiers. II. Commonly Used Semiconductor Devices   The diodes have many roles. Ordinary diodes can be used for rectification, light-emitting diodes can be used for indicator and lighting, regulators can be regulated, varactor diodes can be used for signal modulation. The mold course related to the part of the diode is relatively simple. And many characteristics of the FET are similar to the transistor, so we often explain transistor or amplifier instead.    The basic function of the transistor is to enlarge. The transistor constitutes a variety of circuits because of its features, reflecting a lot of engineering ideas. The transistor-based circuit is the amplifier whose input sound is small, the output sound is great. Amplifier output and the input voltage (or current) ratio is called magnification, also known as gain. For a voltage, if the time for the horizontal axis, voltage vertical axis for mapping, the graph is the voltage waveform. If an amplifier with a gain of 5 inputs a constant voltage of 1V (the waveform on the left is shown below), the output should always be 5V (the waveform is shown in the middle figure below), neither changing with time nor changing with temperature And the input voltage exactly the same shape. However, if the magnification is unstable and constantly changing, the original input signal will be distorted (as shown on the right), and the signal may change from a horizontal straight line to a curved line. This waveform change is called distortion. Voltage waveform   III. Negative Feedback Basic Concepts   The basic concept of negative feedback makes some very powerful people find a good way: negative feedback. What is negative feedback? "Feedback refers to the output of the system is returned to the input and affect the input, thus affecting the overall system output Feedback can be divided into positive feedback and negative feedback is to make the output and input the opposite effect, the system Output tends to be stable. "The above explanation is hard to make sense. I have two examples. When playing the inverted pendulum, we propped up an inverted wooden stick by hand. When the wooden stick was tilted in one direction, we offset the change by moving the hand to the direction of the stick so that the stick could be in our hand's balance.    When I was in high school, I often had a monthly test. I found that some of my classmates had a habit of starting a good study when a test score was poor and going up next time. When the test was better, the next month will be relaxed, so results will come down again, so again and again. Both of these examples illustrate that negative feedback can make the system more stable. We ignore the specific circuit, only draw a simple diagram to illustrate how the transistor amplifier uses the negative feedback. The triangle below shows a transistor consisting of an amplifier, the magnification is A, the input is I, the output O = I * A, because the magnification A instability, so the output waveform will be distorted.  Negative feedback   Some devices have been added to the circuit as follows. The purple circle is the adder, combined with the purple "+", "-" symbol that its output Y = (+ I) + (- X) = I-X, in the actual circuit with the resistance can be achieved; Block F is the feedback device, which means that the signal is taken out from the output O and multiplied by F to get X, so X = O * F, where F <1 (this part can be realized by resistance in the actual circuit). Triangle refers to the amplifier A, mainly composed of transistors, meeting O = A * Y, and A magnification is unstable, easy to be disturbed. Add a feedback device   You can list the equations: Y = I-XO = Y * AX = O * F to calculate the gain of the entire circuit: Formula   If the magnification A is very large, while F is not small, A * F 》》1 symbol "》》" suggests far greater than the approximate idea. The entire circuit magnification: Formula   IV. Operational Amplifier Development   1.Working principle of operational amplifier Because the feedback device can be realized by the resistance, the resistance value of the ordinary resistance is not easily disturbed by the outside world, so the value of F is very steady, so the magnification of the whole circuit is very steady. We succeeded in solving the stability problem of the transistor by negative feedback. We can see here that the feedback part and the amplification part form a ring, so the amplification of the whole circuit is called the loop gain or the closed-loop gain. Before adding the feedback, the amplification of circuit A is called the open-loop gain. Due to the negative feedback, the stability of the circuit is improved, but there is also a cost: Because the AF 》》1, then "A》》1 / F" open-loop gain is much larger than the closed-loop gain, which means the amplifier gain is greatly reduced. But in general, this is worth it for stability. Operational amplifier In the above circuit, in order to actually create a large open-loop amplifier gain A, often with multi-stage transistor amplifier in series design.   Because the high demand for such high-gain amplifiers is very common, so some people in history put them into a finished circuit board module. This is used directly as a component on the line when needed because it’s very convenient. This is the original op-amp, which is referred to as op-amp. The development of integrated circuits makes a large number of transistor components integrated into a small chip possible, so the common integrated operational amplifier turns up today.    The "op-amp" is named for its mathematical operation originally used to simulate computers. Although now widely used digital computer is no longer used to calculate the operational amplifier, but the name still retained. Today, op-amps play an important role in analog circuits and have also become one of the focuses of the analog circuit. The op-amp has virtual short and virtual interrupt characteristics. Usually, op-amp has two inputs U + and U-, an output Uo, between them to meet Uo = A * (U + -U-) op-amp open-loop gain A often up to dozens Million ~ millions, but the op-amp output voltage limited by the supply voltage can not exceed the supply voltage. So the op-amp input-output relationship similar to the shape below. In the figure, the horizontal axis is (U + -U-) and the vertical axis is Uo. Op amp input - output In the middle of a straight line, the op-amp is in the normal state of amplification, called the linear region, meeting Uo = A * (U + -U-). When the absolute value of the input becomes slightly larger, the output will be power limited, no longer satisfying the above relationship. The value of Uo is usually slightly smaller than the supply voltage range (note that the op-amp can be dual supply, that is the supply voltage range can be afloat between a negative value and a positive value), which is called the non-linear region. Rail-to-rail op-amp output can reach the power supply voltage.   When the operational amplifier in the linear region, the Uo value is very limited, but A large. So U + -U- = UoA ≈ 0 or U + ≈ U-. At this time, the positive and negative op-amp input voltage is almost equal, like a short circuit similarly, which is called a short circuit. So only when the operational amplifier in the enlarged area will have "virtual short" characteristics, rather than the inherent properties of the op-amp. On the other hand, due to the internal structure of the op-amp, its input impedance is large.    The input impedance can be simply understood as: the input impedance = input voltage/input current input impedance, which means that the op-amp input with only a small current can work properly. Because of this, an op-amp can be used for some weak current detection, such as the human brain, myoelectric wave, whose maximum voltage is only a few mV, the current value is very small. This feature of the op-amp is called a virtual interrupt, meaning that there is almost no current flowing into the input like the open circuit. Different from the short circuit, a virtual interrupt is the inherent properties of the op-amp, which will not change with the circuit.   2.Op amp non-ideal characteristics   The op amp's non-ideal characteristics of the op-amp by the transistor composition. Obviously, like the transistor, there will be many undesirable characteristics. The actual operational amplifier will not fully meet the short virtual fault characteristics. Its normal work needs input current input, which is called the input bias current.    The same op-amp input offset voltage, input offset voltage, input offset current, and other non-ideal parameters. These non-ideal characteristics, such as the input bias current is small, sometimes will have a great impact on the circuit, resulting in the circuit does not work. Therefore, there are some ways to reduce the impact of these factors. In practical applications, the non-ideal characteristics of the op-amp are a very important issue. There are many ways to eliminate the non-ideal characteristics of the op-amp, but not introduced here.    Other cores of the molding course are the transistor and op-amp. Around these devices, the molding course will explain a variety of circuits, including the calculation of the amplifier circuit analysis, multi-stage amplifier circuit, the amplifier frequency characteristics, the idea of feedback, power amplifier circuit, comparator, oscillator, integrator, differentiator, waveform generation, Signal processing, filter, integrated power supply circuit and so on. When comparing op-amp and transistor In the actual design of the circuit, the op-amp will be more than the transistor. Because many of the features of op-amps are better than triodes, the circuit design is simple, and the cost of op-amps is often not too high.   Many times you can achieve the same effect with the transistor and op-amp and lower cost of each op-amp. Because op-amps integrate a large number of transistors, the average cost per transistor is very low. For example, a conventional audio pre-amplifier can be handled with a universal op-amp. and if you use the transistor, you may need more transistors, and the human cost during design is far higher than the op-amp program. Of course, the transistor has its advantages.    In some very simple circuits, the stability of the magnification is not strictly required, one or two transistors can accomplish. And triodes are often used to save costs. In addition, in some extreme conditions, such as working in high-frequency and high-power environments (such as RF signal transmitting circuits), a well-designed triode circuit will perform much better than an op-amp, or at a much lower cost. Even in some conditions, only the transistors can be completed, then you need to choose the transistor to build the circuit.   This video give a detailed explanation about analog circuit: Analog Circuits Lecture V. Conclusion   Analog circuits are a very complex discipline that involves more than knowledge written in books. Books are generally introduced in accordance with the principle of work, simplifying a lot of difficulties to understand, but in reality, more factors must be considered. So the gap between the actual circuit and the book is very large. Such as triangular wave generator built with an op-amp introduced in analog circuit books usually can not work in all likelihood. However, the main principle of the actual circuit is the same as the book description. Therefore, the design of analog circuits often requires a lot of experience, for there are many things that can not be explained and even difficult to calculate. I hope this article can help you learn more about analog circuits. FAQ   1. What is meant by analog circuit? The Analog electronic circuit includes an analog signal with any continuously changeable signal. While working on an analog signal, an analog circuit alters the signal in some manner. Analog circuit can be used to convert the original signal into some other format such as a digital signal.   2. What is the difference between digital and analog circuits? Analog Circuits and Digital Circuits is a classic way of differentiating between two types of electronic circuits based on the signals they process. To put it in simple words, Analog Circuits deals with continuous analog signals whereas Digital Circuits deals with discrete digital signals.   3. Where are analog circuits used? Analog circuits represent key components of communications and other systems in widespread, growing commercial use. High-speed transistors are essential to the operation of such circuits.   4. Is digital cheaper than analog? If you are looking at the straight-up module cost an analog vs. a digital version, then yes, the analog module will likely be a cheaper solution. However, if you look at the total cost, or the “value” of the digital module versus an analog solution, then digital will in fact be “cheaper”.   5. What is analog design? Analog design is part of integrated circuit design and focuses on signal fidelity, amplification and filtering. Those who perform the function of analog design are qualified electrical engineers.   6. Why is analog design difficult? Ask most engineers and they would tell you why: analog design is harder than digital, and requires more knowledge and more factors to consider such as a deep understanding of efficient power, precision measurement, wireless connectivity, and reliable circuit protection.   7. Which is better analog or digital design? Analog circuits can be precise, elegant design with various components with very simple. For example, two resistors joining to make a voltage divider. Generally, Analog circuits are much more complex to design compared to which complete the same task as digitally.   8. What is the tool used for analog circuit design? A suite of web tools to help you design signal conditioning circuits faster: Analog Filter Wizard, Precision ADC Driver Tool, Photodiode Wizard, In Amp Diamond Plot, Direct Digital Synthesis Simulator, and Virtual Eval.   9. How hard is circuit design? Circuit design is a lot like any other learned skill, you start with the basics. These basic circuits can be learned in a few days. ... So yes, it can be very difficult to reach a high level of design expertise and you never really master it because the art continues to evolve.   10. How does circuit design work? Digital electronic circuit design takes the electrical signals in the form of discrete values. The data are represented in the form of zeros and ones. Digital circuits extensively use transistors, interconnected to give create logic gates that provide the function of Boolean logic.   You May Also Like:   Look Forward to the Future of Semiconductor GaN High-Electron Mobility Transistor Power Amplifier Trojans are everywhere even the hardware Remote Electronic Transport Promote Organic Photovaltaic Power Generation Make Next-Gen of Computer Be Faster,Better, More efficient Some suggestions about protecting transformers  

Warm hints: The word in this article is about 3000 words and  reading time is about 10 minutes.SummaryFull bridge push-pull bi-directional DC/DC converters are mostly modeled by state space averaging method with the complex modeling process. Taking the isolated form push-pull bi-directional DC/DC converter as the research object, this article adopted the pulse-width modulation switch model method to obtain the equivalent circuit model of this converter. Based on this model, this article constructed a closedloop control system of the converter under different working modes, carried out the design and verification of voltage control loop and realized the constant voltage charge-discharge control strategy. The experimental and simulation results verify the correctness of the conclusion. CoreFull bridge push-pullPurposeTo obtain the equivalent circuit model of the converterEnglish nameBidirectional DC/DC convertersCategoryElectromechanical deviceFunctionConverting a source of direct current (DC) from one voltage level to anotherFeatureAdopting the pulse-width modulation switch model method CatalogsCatalogs1. Foreword2.2 Modeling of bi-directional DC/DC converter4 Epilogue2. Principle and design2.3 Voltage Closed-loop Control and Simulation 2.1 The working principle of circuit3 Experimental result   Introduction1. ForewordBidirectional DC/DC converters have been widely applied in many fields such as electric vehicles and battery energy storage systems. Bidirectional DC/DC converters have different circuit topologies according to their applications.I have seen some examples of using Buck/Boost converter to realize the bi-directional flow of electric energy. Because there is no transformer in the converter, so the electrical isolation of the high and low voltage side can not be realized, and only a small voltage range has been allowed. In order to solve this problem, it is proposed to use isolation transformer in bidirectional full-bridge DC/DC transform circuit, but the converter uses too many switching devices and therefore causes too many power losses. The isolated full bridge push-pull bi-directional DC/DC converter has been widely used due to the advantages of both types of converters of itself.At present, the state space averaging method is used to deduce the small signal model of bidirectional DC/DC converter, which needs a large amount of mathematical derivations and calculations. In order to simplify the modeling process, the full-bridge push-pull bi-directional DC/DC converter is modeled by using PWM-switch modeling method. The transfer function between output voltage and duty cycle of the converter is obtained in two modes: boost mode and buck mode. In addition , the voltage closed loop control system is constructed based on the derived circuit model, and the voltage loop is designed and corrected by the compensation network , realizing the constant voltage control of the full-bridge push-pull bidirectional DC/DC converter.First step in developing feedback control for a dc-dc converter is modeling. Here, we model the buck converter in terms of average behavior. Detail2. Principle and design2.1 The working principle of circuitFigure 1 shows the topology of the main circuit of full bridge push-pull bi-directional DC/DC converter. ^The power switch tubes S1～S4  are arranged in the form of a full-bridge circuit;^the power switch tubes S5～S6 are arranged in the form of a push-pull circuit;^CHV is a parallel capacitor with HVDC busbar;^CLV is a parallel capacitor with LVDC busbar;^L is a  low-voltage-side energy storage filter inductor;^HV is high-voltage-side DC bus;^LV is a low-voltage-side DC bus.Figure 1 Main circuit of bidirectional DC/DC converterFigure 2 and 3 respectively give the schematic diagrams of the PWM driving waveform of the power switch tube working in boost and buck mode, and the schematic diagram of the voltage waveform of the primary and secondary sides of the transformer. The u12 shown in the diagram is the transformer primary-side voltage and the u34 is the transformer sub-side voltage.Figure 2 Waveforms of the  power switch tube working in boost modeFigure 3 Waveforms of the  power switch tube working in buck mode2.2 Modeling of bidirectional DC/DC converterThe basic idea of PWM-switch modeling method: the nonlinear part will be linearized by taking an average value of the voltage and the current of it in one switching period when it is a stable circuit, and therefore the nonlinear circuit will turn into a linear circuit. The push-pull bidirectional DC/DC converter working in the buck mode can be equivalent to the circuit shown in Fig. 4 (the circuit in the dashed box is meant to indicate the nonlinear circuit), which turns on during [0, DTs] and turns off during [DTs, Ts], where Ts is the switching cycle and D is the duty ratio of the full bridge push-pull bi-directional DC/DC converter turn on. In the mathematical expressions presented in this article, all the uppercase variables represent the steady-state values, and all the lowercase variables represent the instantaneous values.Figure 4 Conducting circuit in buck mode operationIn the equivalent circuit shown in figure 4, the voltage and current are averaged during a PWM switching cycle, among which idc is primary instantaneous current and iL is secondary instantaneous current of transformer; iC is instantaneous current of electric capacity CLV; ucp is the instantaneous voltage between nodes c and p; uap is the instantaneous voltage between nodes a and p; n is the transformation ratio.Assuming that the duty cycle is d=D, now add an AC small signal to its value attachment (where small angle brackets denote AC small signals and the other variables following are the same), the complete instantaneous value expression for duty cycle is as shown in formula 3:Then substituting equation 3 into the original yields equation 1 and 2, so we have:Neglecting the product term of AC small signal, and equation 4 and 5 of  AC small signal can be simplified as equation 6 and 7:The mathematical relations of voltage and current working in steady state (following yields equation 8 and 9) derived from original yields equation 1 and 2, along with equation 6 and 7 can be used to obtain equivalent circuit model of bidirectional DC/DC converter in Buck mode (see the two-port circuit shown in the dashed box of figure 5). The model is linear since the constraint equations describing the two-port circuit are all linear equations. It can be learned from the above modeling process that the linear model of the full bridge push-pull bidirectional DC/DC converter can be easily established by using the switching model modeling method, which has the advantages of less calculation and simple derivation. It can be learned from the above modeling process that the linear model of the full bridge push-pull bidirectional DC/DC converter can be easily established by using the PWM-switch modeling method, which has the advantages of less calculation and simple derivation.The equation 10 gives transfer function between the output voltage and duty cycle of low voltage side bus according to laws of KCL and KVL.Figure 5 gives the equivalent circuit of bidirectional DC/DC in Buck mode obtained from equation 10, among which UHV is the operating voltage of high voltage side bus in steady state, uLV is the instantaneous voltage of low voltage side bus, n is the transformer ratio, R is the load resistance of low-voltage-side DC bus, Uap/D can be regarded as controlled voltage source, and IL/n can be regarded as controlled current source.Figure 5 Small signal equivalent circuit in Buck mode operationThe transfer function between duty cycle and output voltage in Boost mode can be obtained by using the same analysis method as Buck mode, which has shown in equation 11. R1 is the load of high voltage side bus.2.3 Voltage Closed-loop Control and SimulationFigure 6 gives the block diagram of the closed loop control system of small signal circuit model of the full bridge push-pull bidirectional DC/DC converter in two different operating modes. Charge and discharge at constant voltage in two modes can be realized by voltage closed-loop control.What we can see from figure 6:Uref is the given voltage of high-voltage-side and low-voltage-side DC bus; Hv(s) is the transfer function of sampling; Gm(s) is the transfer function of PWM; Gcv(s) is the transfer function of PI of voltage control loop; Gvd(s) is the transfer function of voltage versus duty cycle.Figure 6 Block diagram of voltage closed loop controlTo theoretically verify the correctness of mathematical model establishment and the feasibility of voltage control strategy, we use the PSIM 9.0 software tool for simulation and analysis in this article. Figures 7 and 8 have respectively shown the simulated waveforms in different operating modes. In Buck mode operation, the voltage of low voltage bus can be stabilized at 12V, so the constant voltage charging has been realized; and in Boost mode operation, the voltage of high voltage bus can be stabilized at 400V, so the constant voltage discharge has been realized, which theoretically verifies the correctness of mathematical model establishment and the feasibility of voltage control strategy. u12 and u34 are the voltages of the primary and secondary sides of the transformer respectively, uHV and uLV are voltages of high-voltage side and low-voltage side bus.Figure 7 Simulated voltage waveform in boost mode operationFigure 8 Simulated voltage waveform in buck mode operation Analysis3 Experimental resultIn order to verify the correctness of the small-signal circuit model and the feasibility of voltage feedback control, we built an experimental platform of full-bridge push-pull bi-directional DC/DC converter using TMS320F28035 as the core control chip.Table 1 gives the main circuit parameters of the bidirectional DC/DC converter based on the full bridge push-pull circuit structure.Table 1 Basic circuit parameters of converterFigure 9 gives the output voltage waveform of secondary voltage and low-voltage-side DC bus of transformer in buck mode operation when steady input voltage of high-voltage-side DC bus is 400V (provided by programmable DC power supply) and load resistance of low-voltage-side DC bus is 0.1Ω (provided by programmable DC electronic load). Here the output current of low-voltage-side DC bus iL is stable at about 120A, the output voltage uLV is about 12V, and the output power of low-voltage-side bus Po is about 1.5kW which meets the requirement of rated power designed, now we have realized  the constant-voltage charging of low-voltage-side DC bus.Figure 9 The voltage waveform in Buck mode operationFigure 10 gives the output voltage waveform of primary voltage and  high-voltage-side DC bus of transformer in boost mode operation when steady input voltage of low-voltage-side DC bus is 12V (provided by low-voltage DC power supply) and load resistance of high-voltage-side DC bus is 105Ω (provided by high voltage resistance load box). Here the output current of high-voltage-side DC bus iH is stable at about 3.7A, the output voltage of high-voltage-side DC bus uHV is stable at about 400V, and the output power of high-voltage-side bus Po is about 1.5kW which meets the requirement of rated power designed, until now we have realized  constant-voltage discharge of high-voltage-side DC bus.Due to the high level at the output, technical problems in the winding process for power transformers and the whole experimental device completing by manual welding, the rate of heat dissipation of power transformer appears to be somewhat low and the parasitic inductance and inductive coupling is also rocking the boat, and then we see the voltage waveform oscillation at zero crossing of transformer voltage in Boost mode moderation. However, under the condition of steady state parameters, this experimental platform can work normally and stably for a long time according to the design requirements and can meet the needs of practical applications.Figure 10 The voltage waveform in Boost mode operationFigure 11 is a schematic diagram of the hardware platform which is mainly composed of main circuit board, control circuit board and corresponding test equipment.Figure 11 physical photographs of experimental devices4 EpilogueAccording to the characteristics of bidirectional DC/DC converter applied in fields of battery and electric vehicle energy storage management, a bidirectional DC/DC converter based on full-bridge push-pull topology is obtained by comparing with different circuit topologies. Different from the traditional state-space average modeling, the method of PWM-switch modeling is used now to build small signal equivalent circuits in different mode operations, and the voltage loop has also been designed and corrected. The high-power constant voltage charging is realized in Buck mode moderation and the high-power constant voltage discharge is also realized in boost mode operation. Both modes can work normally and stably to meet the performance requirements of practical applications, which appear to be in high value at fields of battery and electric vehicle energy storage management. Book SuggestionSoft-Switching PWM Full-Bridge Converters: Topologies, Control, and DesignJun 23, 2014This book intends to describe systematically the soft-switching techniques for pulse-width modulation (PWM) full-bridge converters, including the topologies, control and design, and it reveals the relationship among the various topologies and PWM strategies previously proposed by other researchers. The book not only presents theoretical analysis, but also gives many detailed design examples of the converters.---by Xinbo RuanPower Electronics: Converters and RegulatorsOct 28, 2016This book is the result of the extensive experience the authors gained through their year-long occupation at the Faculty of Electrical Engineering at the University of Banja Luka. Starting at the fundamental basics of electrical engineering, the book guides the reader into this field and covers all the relevant types of converters and regulators. Understanding is enhanced by the given examples, exercises and solutions. Thus this book can be used as a textbook for students, for self-study or as a reference book for professionals.---by Branko L. Dokić and Branko BlanušaPulse-Width Modulated DC-DC Power ConvertersOct 26, 2015With improved end-of-chapter summaries of key concepts, review questions, problems and answers, biographies and case studies, this is an essential textbook for graduate and senior undergraduate students in electrical engineering. Its superior readability and clarity of explanations also makes it a key reference for practicing engineers and research scientists. Following the success of Pulse-Width Modulated DC-DC Power Converters this second edition has been thoroughly revised and expanded to cover the latest challenges and advances in the field.---by Marian K. Kazimierczuk Relevant information "Modeling and Control of Full Bridge Push-Pull Bi-Directional DC/DC Converter"About the article "Modeling and Control of Full Bridge Push-Pull Bi-Directional DC/DC Converter", If you have better ideas, don't hesitate to  write your thoughts in the following comment area. You also can find more articles about electronic semiconductor through Google search engine, or refer to the following related articles:How to Learn Analog Circuit DesignLook Forward to the Future of Semiconductor

  In this article today, you will learn what transistor is, how does it work, how long is its history, and how many kinds of transistor are there, how to replace one when your transistor is broke and so many more. Say no more and off we go.     Catalog I. What is a Transistor? 1.1 General View 1.2 Transistor Structure and Operation II. Transistor History III. Transistor Development IV. Transistor Advantage V. Transistor Classification VI. Transistor Power Control VII. Transistor Test Replacement VIII. How to Judge the Electrode of a Transistor IX. Transistor Replacement Principle FAQ   I. What is a Transistor?   1.1 General View Transistors make our electronics world go round. They're critical as a control source in just about every modern circuit. Sometimes you see them, but more-often-than-not they're hidden deep within the die of an integrated circuit.    The transistor is a kind of solid semiconductor device. It has many functions, such as detection, rectifier, amplifier, switch, voltage stabilizer, signal modulation, and so on. As a variable current switch, transistors can control output currents based on input voltages. Unlike conventional mechanical switches (such as relay, switch), transistors use telecommunication signals to control their opening and closing, and the switching speed can be very fast, for example, the switching speed in the labs can be higher than 100GHz. Strictly speaking, transistors refer to all single components based on semiconductor materials, including diodes, transistors, field-effect transistors, silicon control, and so on. In addition, transistors usually mean crystal triodes.   The transistors are divided into two main categories: bipolar junction transistors (BJT) and field-effect transistors (FET).   The transistor has three poles. The three poles of bipolar junction transistor, composed of the emitter(made up of N-type and P-type), base, and collector respectively. For the field-effect transistors, they are the source, gate, and drain respectively.   Because the transistor has three polarities, there are also three ways to use them, namely, emitter grounding (called common emitter amplification, CE configuration), base grounding (called common base amplification, CB configuration), and collector grounding (called common set amplification, CC configuration, emitter-coupled logic). Transistors are semiconductor devices, which are commonly used as amplifiers or electrically controlled switches. Transistors are important components that regulate the operation of computers, mobile phones, and all electronic devices. Due to their high response speed and accuracy, transistors can be used for a wide variety of digital and analog functions design, including amplifiers, switches, and voltage stabilizers, signal modulation, and oscillator circuits. Transistors can be packaged independently or in a very small area, which can accommodate 100 million or more transistors integrated into a part of the circuit.   1.2 Transistor Structure and Operation   Transistors are made by stacking three different layers of semiconductor material together. Some of those layers have extra electrons added to them, which called “doping”, and others have electrons removed (doped with “holes” – the absence of electrons). A semiconductor material with extra electrons is called an N-type (negative) and a material with electrons removed is called a P-type (positive).    With some hand waving, we can say electrons can easily flow from N-regions to P-regions if they have a little force (voltage) to push them. But flowing from a P-region to an N-region is really hard (requiring more force—voltage).    The NPN transistor is designed to pass electrons from the emitter to the collector (the conventional current flows from collector to emitter). The emitter emits electrons into the base, which controls the number of electrons. In fact, most of the electrons emitted are “collected” by the collector, which sends them along to the next part of the circuit.   A PNP has a little special area. The base still controls current flow, but that current flows in the opposite direction, that is, from emitter to collector, instead of electrons, the emitter emits “holes” which are collected by the collector.   The transistor is kind of like an electron valve. The pin of the base is likely to a handle you can adjust to allow more or fewer electrons to flow from emitter to collector.     II. Transistor History   The invention of transistors can date back to the middle& later 1920s, an engineer Physicist Julius Edgar Lilienfeld filed a patent for a field-effect transistor (FET) in Canada in 1925, which was intended to be a solid-state replacement for the triode. Lilienfeld also filed identical patents in the United States in 1926 and 1928. However, it was limited to the technical level at the time, the material used to make it couldn’t meet the high-quality requirement, making it impossible to actually construct a working device at that time.   In December 1947, the first practically implemented device was a point-contact transistor invented by American physicists John Bardeen, Walter Brattain, and William Shockley from Bell Labs. Due to the complex manufacturing process of point-contact transistors, many products fail, and it also has disadvantages, such as high noise, difficulty to control when power is high and narrow application range. To overcome these shortcomings, Shockley put forward the idea of replacing metal-semiconductor contacts with a "rectifier junction", and they also proposed the working principle of it. The transistor revolutionized the field of electronics and paved the way for smaller and cheaper radios, calculators, and computers, among other things. The transistor is on the list of IEEE milestones in electronics, and Bardeen, Brattain, and Shockley shared the 1956 Nobel Prize in Physics for their achievement.   In 1950, the first P-N junction transistor came out, and its performance was exactly the same as the assumption of William Shockley. Most of today's transistors are still P-N junction transistors. (the so-called P-N junction is a combination of P-type and N-type, and P-type multiplex with holes, N-type multiplex with electrons.)   In the first test, it can amplify the audio signal 100 times, its shape is shorter than the firewood stick but thicker. In naming the device, Walter Brattain thought of its resistive conversion properties, that is, it works on a transfer current from "low-resistance input" to "high-resistance output," so it's called trans-resistor, later this abbreviated as a transistor.   The innovation of transistors was a major invention in the 20th century and the forerunner of the microelectronics revolution. Because the transistor is the key active component in practically all modern electronics. With it, a small, low-power-consuming electronic device can be used to replace a large, high-power-consuming electronic tube. What's more, the development of integrated circuits based on the invention of transistors.   In 2016, a team at Lawrence Berkeley National Laboratory broke the physical limit and cut the most sophisticated transistor process available from 14nm to 1nm, making a breakthrough in computing technology.   III. Transistor Development   1) vacuum triode In February 1939, there was a great discovery in the Bell Labs, the birth of a silicon PN junction. In 1942, a student, Seymour Benzer, was on a team led by Lark_Horovitz at Purdue University,  found that monocrystalline germanium has excellent rectifying performance which other semiconductors do not. These findings laid the groundwork for the later invention of transistors.    A triode is a vacuum tube with three electrodes which are cathode, anode, and a control grid. The function of an additional third electrode is to serve as an electrostatic screen that shields the cathode from the electrostatic field of anode triode is used for amplification of weak AC signals of frequency ranging from 0 to 100 MHz.   2) point-contact transistor The point-contact transistor is the first type of transistor to be successfully demonstrated. It was developed by research scientists John Bardeen and Walter Brattain at Bell Laboratories in December 1947. Bardeen and Brattain applied two closely-spaced gold contacts held in place by a plastic wedge to the surface of a small slab of high-purity germanium. The voltage on one contact modulated the current flowing through the other, amplifying the input signal up to 100 times. The group had been working together on experiments and theories of electric field effects in solid-state materials, with the aim of replacing vacuum tubes with a smaller device that consumed less power.   3) bipolar and unipolar transistors On the basis of bipolar transistors, Shockley put forward the concept of unipolar junction transistors in 1952, which is called junction transistors today. Its structure is similar to that of PNP or NPN bipolar junction transistors, but there is a depletion layer at the interface of P_N to form a rectifier contact between the gate and the conductive channels of source and drain. At the same time, both ends of the semiconductor as the gate to adjust the current between the source and drain.    4) silicon transistors The first working silicon transistor was developed at Bell Labs on January 26, 1954, by Morris Tanenbaum. The first commercial silicon transistor was produced by Texas Instruments in 1954. Silicon transistors and germanium transistors have the function of current amplification. The difference is that the threshold voltage(Even if the positive voltage is applied, it must reach a certain value before it can start to turn on. This is called threshold voltage, for silicon transistor, it is about 0.7V and for germanium transistor is about 0.3V) of silicon transistor is larger than that of germanium transistor; the reverse current of the silicon transistor is much smaller than that of the germanium transistor; the maximum operating temperature of the silicon transistor is higher than that of the germanium transistor; the stability of the silicon transistor is better than that of the germanium transistor.   5) integrated circuit (IC) After the invention of the silicon transistor in 1954, the great application prospect of the transistor has become more and more obvious. The next goal of scientists is how to connect transistors, conductors, and other devices efficiently. The invention of transistors gives birth to the integrated circuit as time requires. As we all know, an IC is a collection of electronic components—resistors, transistors, capacitors, etc.—all stuffed into a tiny chip and connected together to achieve a common goal today.   6) field-effect transistors(FET) and metal-oxide-semiconductor field-effect transistor(MOSFET) The field-effect transistor was first patented by Julius Edgar Lilienfeld in 1926 and by Oskar Heil in 1934, but practical semiconducting devices (the junction field-effect transistors) were developed later after the transistor effect was observed and explained by the team of William Shockley at Bell Labs in 1947. The basic principle of the field-effect transistor was first patented by Julius Edgar Lilienfeld in 1925. In 1959, Dawon Kahng and Martin M. (John) Atalla at Bell Labs invented the metal-oxide-semiconductor field-effect transistor (MOSFET) as an offshoot to the patented FET design. In 1962, Stanley, Heiman, and Hofstein in an RCA device integrated study group found that a MOS tube can be constructed by a conductive strip, a high-resistance channel region, an oxide layer, and an insulating layer on a Si substrate through diffusion and thermal oxidation.   7) CPU A central processing unit (CPU), also called a central processor or main processor, is the electronic circuitry within a computer that carries out the instructions of a computer program by performing the basic arithmetic, logic, controlling, and input/output (I/O) operations specified by the instructions. But fewer people know that modern CPUs contain millions of individual transistors that are microscopic in size. Because transistors are the building blocks of the integrated circuits, and more transistors in CPUs means higher processing efficiency.     IV. Transistor Advantage   Compared with the electron tube, the transistor has many advantages:   （1）Fewer consumption No matter how good an electron tube is, it will gradually deteriorate due to changes in cathode atoms and chronic gas leakage. For technical reasons, the same problem existed at the beginning of transistor fabrication. With advances in materials and improvements in many ways, transistors live typically 100 to 1000 times longer than electron tubes.   Consumption of electric energy is only 1/10 or dozens of times of the electron tube. It does not require heating the filament to produce free electrons like an electron tube. For example, a transistor radio can be listened to for half a year or more long with a few dry batteries, which is difficult for an electronic tube radio.   （2）No need to preheat Work as soon as you turn on the machine. For example, a transistor radio, you can hear the sound as soon as it turns on, and pictures come up quickly when turn on a transistor TV. But electron tube equipment cannot do this. Obviously, transistors have great advantages in electric equipment, medical treatment, industrial measurement, etc.   （3）Solid and reliable More reliable than the tube because of its shock resistance and vibration resistance. In addition, transistors release less heat due to their smaller size, so they can be used in small, complex, reliable circuits. Although the fabrication process of transistors is precise, the process is simple, it is helpful to increase the installation of it on the devices.   （4）Importance Transistors are the key active components in all modern electrical appliances. The importance of transistors in today's society is mainly due to their ability to use highly automated processes for mass production, which greatly reducing unit production costs.   While millions of monolithic transistors are still in use, but most transistors are assembled on microchips (chips) with diodes, resistors, and capacitors to make complete circuits. Analog or digital design or both are integrated on the same chip. The cost of designing and developing a complex chip is quite high, but the price per chip is minimal when the cost apportioned to millions of units.     V. Transistor Classification   According to material The semiconductor material used as a transistor can be divided into silicon material transistors and germanium material transistors. Furthermore, the polarity of the transistor can be divided into four types: germanium NPN transistors and PNP transistors, silicon NPN transistors, and PNP transistors.   According to craft Transistors can be divided into diffusion transistors, alloy type transistors, and planar transistors according to their structure and fabrication process.   According to the current capacity Transistors can be divided into low-power transistors, medium-power transistors, and high-power transistors by current capacity.   According to service frequency Transistors can be divided into low-frequency transistors, high-frequency transistors, and ultra-high-frequency transistors.   According to packaging Types The transistors can be divided into metal, plastic, glass, and ceramic packaging transistors.   According to applications Transistors can be divided into low noise amplification transistors, middle and high-frequency amplification transistors, low-frequency amplification transistors, switching transistors, Darlington transistors, high reversion voltage transistors, damping transistors, phototransistors, and magnetic sensitive transistors, and so on.   The low cost, flexibility, and reliability of transistors make them the general choice for non-mechanical tasks, such as digital computing. In the control of electric appliances and machinery, transistor circuits are also replacing motor equipment because of its lower cost and high efficiency.   Specific Types Expressions   1) transistors It is a semiconductor device with two PN junctions inside and usually three eliciting electrodes outside. The transistor is divided into two main categories: bipolar junction transistor (BJT) and field-effect transistor (FET), which have slight differences in their application in a circuit. A bipolar junction transistor has terminals labeled base, collector, and emitter. A small current at the base terminal (that is, flowing between the base and the emitter) can control or switch a much larger current between the collector and emitter. For a field-effect transistor, the terminals are labeled gate, source, and drain, and voltage at the gate can control the current between source and drain.   2) giant transistor The power transistor is a high voltage, high current bipolar transistor (Bipolar Junction Transistor-BJT), so it is sometimes called Power BJT; its characteristics are: high voltage, high current, good switching characteristics, but the driving circuit is complex, driving power is large; the principle of GTR and ordinary bipolar junction transistor is the same.   3) phototransistor The phototransistor is a device that is able to sense light and alter the current flowing between emitter and collector according to the level of light it receives.   Phototransistors and photodiodes can both be used for sensing light, but the phototransistor is more sensitive in view of the gain provided by the transistor. This makes phototransistors more suitable in a number of applications.   Phototransistors adopt the basic transistor concept as the basis of their operation. In general, a phototransistor can be made by exposing the semiconductor of an ordinary transistor to light. Phototransistors were made by not covering the plastic encapsulation of the transistor with black paint in the early stage.   4) bipolar transistor This is a transistor widely used in audio circuits. The bipolar means the flow of current in two kinds of semiconductor materials. Bipolar transistors can be divided into NPN type or PNP type according to the polarity of operating voltage.    5) bipolar junction transistor—BJT The bipolar junction transistor (BJT) is a type of transistor that uses both electron and hole charge carriers. On the contrary, unipolar transistors, such as field-effect transistors, only use one kind of charge carrier. For their operation, BJTs use two junctions between two semiconductor types, N-type and P-type.   BJTs have two types, NPN and PNP, and are available as individual components, or fabricated in integrated circuits, often in large numbers.   BJTs have an amplification function, concretely, they can amplify current, mainly depending on its emitter current transmission through the base area to the collector. To ensure this transmission process, on the one hand, it requires to meet the internal conditions, that is, the impurity concentration in the emission region needs much larger than the impurity concentration in the base region, and meanwhile, the thickness of the base region should be very small.   On the other hand, the external conditions should be satisfied, that is, the emission junction should be positive bias (adding positive voltage), and the collector junction should be inversely biased. This allows BJTs to be used as amplifiers or switches, giving them wide applicability in electronic equipment, including computers, TVs, mobile phones, audio amplifiers, industrial control, radio transmitters, and so on.   There are many kinds of BJT, according to frequency, high frequency, low frequency, according to power, small, medium, high power, according to the semiconductor material, silicon, and germanium tube. The amplifier circuit consists of the common emitter, common base, and common collector.   6) field-effect transistor(FET) The meaning of "field effect" is that the principle of the transistor is based on the electric field effect of the semiconductor. The field-effect refers to the modulation of the electrical conductivity of a material by the application of an external electric field.   There are two main types of FET: junction FET (JFET) and metal-oxide-semiconductor FET (MOS-FET). Unlike BJT, FET is conducted by only one carrier, therefore, it is also known as a unipolar transistor. It belongs to voltage-controlled semiconductor devices that have the advantages of high input resistance, low noise, low-power consumption, wide dynamic range, easy integration, no secondary breakdown, wide safe working area, and so on.   In a metal, the electron density that responds to applied fields is so large that an external electric field can penetrate only a very short distance into the material. However, in a semiconductor, the lower density of electrons (and possibly holes) that can respond to an applied field is sufficiently small that the field can penetrate quite far into the material. This field penetration alters the conductivity of the semiconductor near its surface and is called the field effect. The field-effect underlies the operation of the Schottky diode and of field-effect transistors, notably the MOSFET, the JFET, and the MESFET.   The field effect is to change the direction or magnitude of the applied electric field perpendicular to the surface of the semiconductor to control the density or type of most carriers in the conducting layer (channel) of the semiconductor. The current in the channel is modulated by voltage, and the working current is transported by most carriers in the semiconductor. This type of transistor, which has only one polar carrier to conduct electricity, is also called a unipolar transistor.    Compared with bipolar transistors, FET is widely used in various amplifiers, digital circuits, and microwave circuits because of its high input impedance, low noise, high limit frequency, low power consumption, simple manufacturing process, and good temperature characteristics.    7) static induction transistor The static induction transistor(SIT), which was born in 1970, is actually a junction field-effect transistor. A high-power SIT device can be made by changing the transverse conductive structure of a small-power SIT device used for information processing into a vertical conductive structure. The operating frequency of SIT is comparable to that of the power MOSFET, or even higher than that of the electric MOSFET. The power capacity is also larger than the power MOSFET, so it is suitable for high-frequency and high-power devices. At present, it has been used in radar communication equipment, ultrasonic power amplification, pulse power amplification, and high-frequency induction heating, and so on.   However, the SIT is conducted when no signal is added to the gate, and the gate is turned off when the negative bias is applied, which is called the normal on-type device, thus it is inconvenient to use. In addition, due to the large on-state resistance and consumption of SIT, it has not been widely used in most power electronic devices.   8) single-electron transistor A kind of transistor that can record signals with one or a small number of electrons. With the development of semiconductor etching technology, more and more large-scale integrated circuits can be made. It is considered an important component of nanotechnology, single-electron transistors provide high operating speed and low power consumption.   Single-electron transistors are usually made by keeping two tunnel junctions in series. The transistor consists of a source electrode and a source-drain, which is joined with the help of a tunneling island that is also connected to a gate capacitively. The electrons can flow to another electrode only through the insulator. There are two categories of single-electron transistors: metallic and semiconducting. The former makes use of a metallic island, and its electrodes using a shadow mask are mostly evaporated onto an insulator. The latter, on the contrary, depends on severing the two-dimensional electron gas that forms at the interface of the semiconductors for the junction.   Insulated-gate bipolar transistor(IGBT) is also a three-terminal device: gate, collector, and emitter. It combines the advantages of the giant transistor and power MOSFET. Therefore, it is widely used in many fields due to its sound characteristics.   a. main parameters The main parameters of the transistor include current magnification factor, dissipation power, frequency characteristic, maximum collector current, maximum reverse voltage, reverse current, and so on.   b. amplification coefficient DC current magnification factor also called static current magnification factor or DC magnification factor. It refers to the ratio of transistor collector current to base current, which is usually expressed by hFE or β when the static signal input is not changed.   c. ac magnification AC magnification also called AC current magnification factor or dynamic current magnification factor. It refers to the ratio of transistor collector current variation to base current variation in AC state. In addition, the two parameters are close at a low-frequency state.   d. dissipation power Dissipation power is also called the maximum allowable dissipation power of the collector, which refers to the maximum dissipation power of the collector when the transistor parameter does not exceed the prescribed allowable value.   The dissipation power is closely related to the maximum allowable junction and collector current of the transistor. The actual power consumption of transistors is not allowed to exceed the maximum allowable dissipation power value, otherwise, the transistor will be damaged by overload.   The transistor whose dissipation power is less than 1W is usually called the low-power transistor, that value is equal to or greater than 1W, and less than 5W, such transistor is called the medium-power transistor; whose value is equal to or greater than 5W is called the high-power transistor.   When the operating frequency of the transistor exceeds the cutoff frequency fβ or fα, the current amplification factor β will decrease with the increase of characteristic frequency fT(fT refers to the operating frequency of the transistor when the β value is reduced to 1).   Usually, the transistors whose fT is less than or equal to 3MHZ are called low-frequency transistors; transistors whose fT is greater than or equal to 30MHZ are called high-frequency transistors; those whose fT is greater than 3MHZ and less than 30MHZ are called intermediate frequency transistors.   e. maximum frequency fM The maximum oscillation frequency is the corresponding frequency when the power gain of the transistor is reduced to 1. In general, the maximum oscillation frequency of high-frequency transistors is lower than the common base cutoff frequency fα, while fT is higher than the cutoff frequency fα of the common base and lower than the cutoff frequency fβ of the common collector.   f. maximum current Collector maximum current is the maximum current allowed by transistor collector. When the collector current of the transistor exceeds it, the β value of the transistor will change obviously, which will affect the normal operation of the transistor and even damage it.   g. maximum reverse voltage Maximum reverse voltage is the maximum operating voltage that the transistor is allowed to apply. It includes collector-emitter reverse breakdown voltage, collector-base reverse breakdown voltage, and emitter-base reverse breakdown voltage.   (1) Collector-collector reverse breakdown voltage This voltage refers to the maximum allowable reverse voltage between the collector and emitter when the base of the transistor is open circuit, usually expressed in VCEO or BVCEO.   (2) Base-base reverse breakdown voltage This voltage refers to the maximum allowable reverse voltage between the collector and the base when the transistor emitter is open circuit, expressed in VCBO or BVCBO.   (3) Emitter-emitter reverse breakdown voltage This voltage refers to the maximum allowable reverse voltage between the emitter and the base when the collector of the transistor is open circuit, expressed in VEBO or BVEBO.   (4) ICBO: reverse current between collector and base electrodes ICBO, also called collector junction reverse leakage current. It refers to the reverse current between collector and base when the emitter of the transistor is open circuit. ICBO is sensitive to temperature, thus the smaller the value is, the better the temperature characteristic of the transistor is.   (5) ICEO: the reverse breakdown current between collector and emitter refers to the reverse leakage current between the collector and emitter when the base of the transistor is open. The smaller the current, the better the performance of the transistor.   h. switches It is a most fundamental application of a transistor is using it to control the flow of power to another part of the circuit, that is, using it as an electric switch. Applying it in either cutoff or saturation mode, the transistor can create the binary on/off the effect of switches.   A transistor switch is a critical circuit-building block; it is used to make logic gates, which go on to create microcontrollers, microprocessors, and other integrated circuits.   VI. Transistor Power Control   Today's power transistors can control hundreds of kilowatts of power, and using power transistors as switches has many advantages, mainly as follows:   (1) Easy to turn off and few auxiliary components needed. (2) The switching speed is quick and works at a very high frequency. (3) The voltage resistance range is wide.     Performance improvement of power transistors. Such as:   (1) An increase in the effective working area of switching transistors. (2) Technical processing simplification. (3) Recombination of transistors. (4) The progress of base driving technology for the high power switch. Today's base driving circuits not only drive power transistors but also protect power transistors, which are called "non-centralized protection" (as opposed to centralized protection). The functions of the integrated drive circuit include:   (1) Turning-on and turning-off power switches. (2) Monitoring auxiliary power supply voltage. (3) Limiting maximum and minimum pulse width. (4) Thermal protection. (5) Monitoring saturation voltage drop of switches.     VII. Transistor Test Replacement   The transistors in the circuit mainly include crystal diode, transistor, thyristor, field-effect transistor, and so on. The most commonly used transistor and diodes are the transistor and diode. How to correctly judge the good or bad of the transistors is one of the keys to maintenance.   The key function of an ideal diode is to control the direction of current flow. Current passing through a diode can only go in one direction, called the forward direction. Currently trying to flow the reverse direction is blocked. They’re like the one-way valve of electronics.   If the voltage across a diode is negative, no current can flow, and the ideal diode looks like an open circuit. In such a situation, the diode is said to be off or reverse biased.   As long as the voltage across the diode isn’t negative, it’ll “turn on” and conduct current. Ideally, a diode would act like a short circuit (0V across it) if it was conducting current. When a diode is conducting current it’s forward biased (electronics jargon for “on”).   First of all, we should know whether the diode belongs to a silicon tube or a germanium tube. The forward voltage drop of the germanium tube is generally between 0.1~0.3V, while that of the silicon tube is generally between 0.6~0.7V. The method of measurement is as follows: two multimeters are used. one multimeter is used to measure the forward resistance and another multimeter is measuring the voltage drop of its tube. Therefore, whether germanium tube or silicon tube can be judged according to the voltage drop values. In addition, the greater the difference between the positive and negative resistance of the measured diode, the better.    For example, the forward resistance is several hundred or thousands of ohms, and the reverse resistance is more than tens of kilos, it can be concluded that the diode is good. And meanwhile, the positive and negative electrodes of the diodes can be determined: when the measured resistance values are hundreds of ohm or thousands of ohm, it indicates that is the positive resistance. In addition, if the forward and backward resistance is infinite, it indicates the internal breakage; if the forward and backward resistance is the same, there is also a problem with such a diode; and the forward and backward resistance is zero to indicate the short circuit.   Crystal Triode: It mainly plays an amplification role, so how to determine the amplification capacity? The method is as follows: the multimeter is adjusted to the level R×100 or R×1K. When the NPN tube is measured, the positive meter pen is connected with the emitter and the negative meter pen is connected with the collector, the finally measured value should be thousands of ohm. Then a 100kΩ resistor is connected in series between the base and collector, and the resistance measured by the multimeter should be significantly reduced. The greater the change, the stronger the amplification ability of the transistor. If the change is small or no change at all, that means the transistor does not have amplification ability or this ability is very weak.     VIII. How to Judge the Electrode of a Transistor   Using R×100 level of multimeter germanium transistors to measure and for silicon transistors is R×1K. The red meter pen is in contact with an electrode, and the other two electrodes are measured by a black meter pen. If you can’t find two small resistors, you can move the red meter pen to the other electrodes to measure continuously. Neither works, you can move the black meter pen.   When two small resistors are found, the measuring electrode of the fixed meter pen is the base. If the fixed meter pen is a black pen, the transistor is the NPN type, and if the fixed one is a red pen, the transistor is a PNP type.     A. method for judging resistances of collector and emitter A multimeter is used to measure the resistance at the extreme poles of the base removal, and the exchange meter pen is measured twice. In the case of a germanium tube, the smaller resistance is measured for the first time. In the case of the PNP type, the black meter pen is connected to the emitter, and the red meter pen is connected with a collector electrode as if it is an NPN type. The black meter pen is connected to the collector, the red meter pen is connected to the emitter; If it is a silicon tube, the first time the measured resistance is larger if it is PNP type, the black meter pen is connected with the emitter, the red meter pen is connected with the collector, if the type is NPN, the black meter pen is connected with the collector, and the red meter pen is connected with the emitter.   B. PN junction forward resistance method Measuring the forward resistance of two PN junctions, the value of the emitter is larger and the value of the collector is smaller.   C. amplification coefficient method Using the two-meter pens of the multimeter to contact the two electrodes except for the base, if it is PNP, using the finger to touch the base and the electrode that red meter pen connected to see the swing of the pointer. Change the meter pens to test again, selecting the large swing. At this time, the electrode of the red meter pen connected is the collector. If it is NPN, using the finger to touch the base and the electrode that the red meter pen connected to see the swing of the pointer. Change the meter pens to test again, selecting the large swing, at this time, the electrode of the black meter pen connected is the collector.   Note: The between analog multimeter and the digital multimeter is different. For the analog multimeter, the red meter pen is connected to the negative pole of the power supply, whereas the digital meter is the opposite.     IX. Transistor Replacement Principle   The replacement principle of transistors can be summarized as three: same type, similar characteristics, and similar appearance.   One—same type 1.The material is the same, that is, the germanium tube replaces the germanium tube, silicon tube replaces the silicon tube.   2.The polarity is the same, that is, NPN-type tube replaces NPN-type tube and PNP-type tube replaces PNP-type tube.    Two—similar characteristics The characteristics of the transistors used for replacement should be similar to those of the original transistors, and their main parameter values and characteristic curves should not differ much.    1. Maximum DC dissipation power (PCM) of collector board   PCM of the replaced transistor is generally required to be equal to or larger than the original transistor. However, in a practical test, if the actual DC dissipation power of the original transistor in the whole circuit is much smaller than its PCM, it can be replaced by a transistor with a smaller PCM.   2. Maximum allowable DC current (icm) of collector   Icm of replacing transistor is generally required to be equal to or larger than the original transistor.   3. Breakdown voltage   Transistors for replacement must be able to withstand the maximum operating voltage throughout the machine.   4. Frequency characteristics   The frequency characteristic parameters of transistors are as follows:   (1) characteristic frequency ft: it refers to the frequency when the test frequency is high enough of the common emitter current magnification factor. (2) cutoff frequency fb: When replacing transistors, the main consideration is ft and fb. Transistors usually required for replacement should not be less than the corresponding ft and fb of the original one.   5. Other parameters   In addition to the above main parameters, for some special transistors, the following parameters should be taken into consideration when replacing:   (1) For low noise transistors, transistors with small or equal noise coefficients should be used in replacement. (2) For transistors with automatic gain control performance, transistors with the same automatic gain control characteristics should be used during replacement. (3) For the switch tube, the related switching parameters should be considered when replacing the switch tube.    Three—similar appearance The small power transistors are similar in shape, so long as the lead line of each electrode is marked clearly, and the order of the lead line is the same as that of the tube to be changed, it can be replaced. The appearance of high-power transistors is quite different. In order to install well and maintain normal heat dissipation conditions, the transistors with similar appearance and same size should be selected for replacement.   FAQ   1. What is a transistor and how does it work? A transistor is a miniature electronic component that can do two different jobs. It can work either as an amplifier or a switch: When it works as an amplifier, it takes in a tiny electric current at one end (an input current) and produces a much bigger electric current (an output current) at the other.   2. What are transistors used for? Transistor, semiconductor device for amplifying, controlling, and generating electrical signals. Transistors are the active components of integrated circuits, or “microchips,” which often contain billions of these minuscule devices etched into their shiny surfaces.   3. What is transistor and its types? Transistors are a three terminal semiconductor device used to regulate current, or to amplify an input signal into a greater output signal. ... There are a varieties and different types of transistors available in today's market including Bipolar, Darlington, IGBT, and MOSFET Transistors.   4. What is the principle of transistor? A transistor consists of two PN diodes connected back to back. It has three terminals namely emitter, base and collector. The basic idea behind a transistor is that it lets you control the flow of current through one channel by varying the intensity of a much smaller current that's flowing through a second channel.   5. What are the two main applications of transistor? Transistors are commonly used in digital circuits as electronic switches which can be either in an "on" or "off" state, both for high-power applications such as switched-mode power supplies and for low-power applications such as logic gates.   6. What is PNP and NPN transistor? In an NPN transistor, a positive voltage is given to the collector terminal to produce a current flow from the collector to the emitter. In a PNP transistor, a positive voltage is given to the emitter terminal to produce current flow from the emitter to collector.   7. Why is more transistors better? By squeezing more transistors into a smaller space, a microprocessor can be produced which does more work in less time (more powerful). It also allows one chip to perform more functions - what used to require several chips can all fit into one chip.   8. How do you read a transistor? The typical format for the transistor is a digit, letter and serial number. The first digit is the number of leads minus one. An ordinary bipolar transistor has three leads, so the first digit for it will be 2. The letter N is for semiconductors, so this will be the letter written on a transistor using this system.   9. How do you connect two transistors together? Two NPN transistors can be connected in series with the collector of the lower transistor connected to the emitter of the upper transistor, figure 4, which provides a way to switch off the load from two different signals. Either input can turn off the load but both need to be on for the load to be on.   10. Are smaller transistors faster? The smaller the transistor, the smaller the gate, and the less charge you have to move around. Fourth, you can make the chip faster. The FET effect is not instantaneous, there is a propogation delay involved. Smaller transistors have a shorter delay, so you can operate at higher clock frequencies.     You May Also Like Basic IGBT Tutorial: Short-circuit Protection and Driving Circuit