The Kynix Blog

 IntroductionPower systems are more complex than we see. In reality, we cannot see components of electricity, but we can inject how it works (or does not work). A current transformer is one of many elements that come together like a puzzle to form electrical power. A CT is made up of a laminated steel core, a secondary winding around the core, and insulating material surrounding the windings in its most basic form.Current transformers can be used in a variety of metering applications and use, including Wattmeters, power factor meters, watt-hour meters, protective relays, and as trip coils in magnetic circuit breakers, or MCBs.  CatalogIntroductionⅠ What is a Current TransformerⅡ Classification and Types of Current TransformerⅢ The function of Current TransformerⅣ Application of  Current TransformerⅤ Current Transformer Ratio and Polarity    5.1 Current Transformer Ratio  5.2 Current Transformer Polarity    5.3 Electrical Drawing Conventions for CT PolarityⅥ  How to Test CT PolarityⅦ  How to Choose The Right Current Transformer7.1 Genres of System7.2 Requirement of PrecisionⅧ Frequently Asked Questions about Current  Transformer  Ⅰ What is a Current Transformer A current transformer is a device that generates an alternating current in its secondary that is proportional to the alternating current in its primary. When a current or voltage is too high to measure directly, this method is applied. The induced secondary current is then appropriate for measuring instruments or processing in electronic equipment that requires isolation between the primary and secondary circuits.Because high-voltage currents are reduced, a standard ammeter can be used to safely monitor the actual electrical current flowing in an AC transmission line.Figure1: current transformers An electrical CT differs from a voltage or power transformer in that its primary winding has only one or a few turns. It also differs from a voltage transformer in that the prime current is not controlled by the secondary load current but rather by an external load. The CT ratio is the number of secondary turns multiplied by the number of primary turns. This ratio is calculated based on the primary conductor passing through the transformer window once. Ⅱ Classification and Types of Current Transformer There are two categories in the current transformer. The first, a measuring current transformer, is applied to conjunct with measuring devices for current magnitude, energy, and power. The other, a protective current transformer, is used in conjunction with protective equipment such as trip coils, relays, and the like.Current transformers are classified into three basic types: wound, toroidal, and bar.  1. Wound Current Transformer–The primary winding of the transformer is physically connected in series with the conductor carrying the measured current flowing in the circuit. The magnitude of the secondary current is determined by the transformer's turns ratio.  2. Toroidal Current Transformer -There is no primary winding in these. Instead, the line carrying the network's current is threaded through a window or hole in the toroidal transformer. Some current transformers have a "split core," allowing them to be opened, installed, and closed without disconnecting the circuit to which they are connected.  3. Bar-type Current Transformer-The primary winding of this type of current transformer is the actual cable or bus-bar of the main circuit, which is equivalent to a single turn. They are fully insulated from the system's high operating voltage and are typically bolted to the current-carrying device. Bar-type Current Transformer.Figure2: the typical current transformer  Ⅲ The function of Current Transformer One of the functions of the current transformer is to be used for measurement, and it is often used for billing or measuring the current of the equipment in operation. When measuring large alternating currents, to facilitate meter measurement and reduce the risk of direct measurement of high-voltage electricity, it is often necessary to use current transformers to convert them into a more uniform current. Thus, current transformers are considered as the role of current conversion and electrical isolation.Another function is protection : It is frequently used in tandem with a relay device. When a short circuit or overload occurs in the line, the current transformer sends a signal to the relay device to cut off the fault circuit, thereby protecting the power supply system's safety. The current transformer used for protection is not the same as the current transformer used for measurement. It can only operate effectively when the current is tens of times greater than the normal current, and it requires reliable insulation as well as a sufficiently great accurate limit. The coefficient has adequate thermal and dynamic stability.  Ⅳ Application of  Current Transformer Current transformers are widely used for measuring current and monitoring power grid operation. Revenue-grade CTs, along with voltage leads, power the electrical utility's watt-hour meter on many larger commercial and industrial supplies.To isolate high-voltage current transformers from the ground, they are mounted on porcelain or polymer insulators. Some CT configurations wrap around the bushing of a high-voltage transformer or circuit breaker, allowing the conductor to be automatically centered inside the CT window.Current transformers can be installed on a power transformer's low or high-voltage leads. A section of a bus bar can sometimes be removed to replace a current transformer.High-voltage current transformers are mounted on porcelain or polymer insulators to isolate them from the ground. Some CT configurations wrap around the bushing of a high-voltage transformer or circuit breaker, allowing the conductor to be centered inside the CT window automatically.  Ⅴ Current Transformer Ratio and Polarity5.1 Current Transformer RatioAt full load, the CT ratio is the ratio of primary current input to secondary current output. A CT with a ratio of 300:5 is rated for 300 primary amps at full load and will generate 5 amps of secondary current when 300 amps pass through the primary.If the primary current changes, so will the secondary current output. For example, if 150 amps flow through a primary rated at 300 amps, the secondary current is 2.5 amps. Figure3: A current transformer's ratio is equivalent to a potential transformer's voltage ratio.  At full load, the CT ratio is the ratio of primary current input to secondary current output. A CT with a ratio of 300:5 is rated for 300 primary amps at full load and will generate 5 amps of secondary current when 300 amps pass through the primary.If the primary current changes, so will the secondary current output. For example, if 150 amps flow through a primary rated at 300 amps, the secondary current is 2.5 amps.   5.2 Current Transformer PolarityThe polarity of a current transformer is determined by the direction in which the coils are wound around the CT's core (clockwise or counterclockwise), as well as the manner in which the secondary leads are brought out of the transformer case.To ensure an appropriate installation, all current transformers are subtractive polarity and will have the following designations: H1 - Primary current, oriented in the direction of the lineH2 - Primary current in the load-facing directionX1 denotes secondary current (multi ratio CTs have additional secondary terminals) Figure4:  Split-Core CT with a 200A rating. Take note of the polarity marking in the center of the core, which indicates the direction of the source. (Split-Core CT with a 200A rating.) Take note of the polarity marking in the center of the core, which indicates the source's direction. (Photo courtesy of Continental Control Systems, LLC.)The H1 primary lead and the X1 secondary lead are on the same side of a subtractive polarity transformer. When the polarity of a CT is indicated by an arrow, it should be installed with the arrow pointing in the direction of the current flow.When installing and connecting current transformers to power metering and protective relays, it is critical to maintain proper polarity.   5.3 Electrical Drawing Conventions for CT PolarityFor current transformers, polarity markings on electrical drawings and diagrams can be made in a variety of ways. Dots, squares, and slashes are the three most common schematic conventions. On electrical drawings, polarity markings represent H1, which should be facing the source.Figure5: Electrical Drawing Conventions for CT Polarity   Ⅵ  How to Test CT PolarityMaterials need:an analog voltmeter9-volt batteryThe factory has occasionally misapplied markings on current transformers. The following test procedure can verify the polarity of a CT in the field with a 9V battery: Step1: Cut the Power SupplyBefore testing, turn off all power and connect an analog voltmeter to the secondary terminal of the CT to be tested. The meter's positive terminal is connected to CT terminal X1, while the negative terminal is connected to X2.  Step2: Connect the 9-volt BatteryConnect the positive end of the 9-volt battery to the H1 side (sometimes marked with a dot) and the negative end to the H2 side with a piece of wire run through the high side of the CT window. It is critical to avoid continuous contact, which will result in a short circuit of the battery.  Step3: Check the PolarityIf the polarity is correct, the momentary contact causes a tiny positive deflection in the analog meter. If the deflection is negative, the current transformer's polarity is reversed. The terminals X1 and X2 have to be switched before the test.Figure6:The factory has occasionally misapplied markings on current transformers. A 9-volt battery can be used to test the polarity of a CT in the field.   Ⅶ  How to Choose The Right Current TransformerWhen selecting a current transformer for any application, there are numerous factors to consider. As this can be confusing, and there is a lot of inaccurate information out there, it can lead to installing the wrong current transformer and having to replace equipment.To avoid this, the first step should be to contact the current transformer manufacturer if you have any questions or concerns about compatibility. Midwest Current Transformer's team is available to answer your questions and ensure that you are using the correct product. Speaking with our team before ordering current transformers ensures that you have the right equipment for the job, avoiding any last-minute decisions and potential confusion. 7.1 Genres of SystemWhen using any genre of the meter or power system, it is critical to use a current transformer that is specifically designed for that system. It is especially important with meters because they are not all uniformly designed. Another way to put it is that the system's metering or protection is matched with the type of current transformer.It is also critical to understand the primary range of the current transformer and ensure that it is compatible with the application. This type of compatibility is provided by the various configurations of the primary and secondary windings.  7.2 Requirement of PrecisionThe degree of accuracy is critical for current transformers used for measurement. Not all current transformers provide high accuracy, and the more specific the requirement, the more important the quality of data measurement provided by the CT.This accuracy rating is classified according to class, with the current having an effect on the accuracy provided by the current transformer. The ability of the current transformer to perform to the required levels is always a factor in making the right choice for protective transformers..The degree of accuracy is critical for current transformers used for measurement. Not all current transformers provide high accuracy, and the more specific the requirement, the more important the quality of data measurement provided by the CT.This accuracy rating is classified according to class, with the current having an effect on the accuracy provided by the current transformer. The ability of the current transformer to perform to the required levels is always a factor in making the right choice for protective transformers. Ⅷ Frequently Asked Questions about Current Transformer 1.What is the use of current transformer?A Current Transformer (CT) is used to measure the current of another circuit. CTs are used worldwide to monitor high-voltage lines across national power grids. A CT is designed to produce an alternating current in its secondary winding that is proportional to the current that it is measuring in its primary. 2.What is the use of CT and PT?CT is used to measure current while PT is used to measure voltage. CT is connected in series while PT is connected in parallel. CT ratio range is from 1 to 5A while the PT range is from 110V. We connect the output parameter from CT to the ampere meter while we connect the PT output to the voltmeter. 3.What do you mean by a current transformer?A current transformer is a device used to produce an alternating current in its secondary, which is proportional to the AC current in its primary. This is primarily used when a current or voltage is too high to measure directly. ... This ratio is based on the primary conductor passing once through the transformer window. 4.How is CT ratio calculated?When analog ammeters are installed, we can easily determine the CT ratio by observing the meter full scale value and then divide that value by 5. Figure 3. Ammeter with a full scale of 150 amps. The meter in Figure 3 has a full scale of 150 amps. 5 Why CT is connected in series?A CT may be considered as a series transformer. The primary current in a C.T is independent of the secondary circuit conditions (burden/load). The primary winding of the CT is connected in series with the line carrying the current to be measured. Hence it carries of the full line current.   

IntroductionThe potentiometer is a three-terminal resistive element whose resistances can be adjusted according to a certain change rule. According to it, it is used in a large variety of electrical and electronic circuits, such as voltage dividers, variable resistor, and current controllers. The potentiometer is usually composed of a resistor body and a movable brush. When the brush moves along the resistor body, the resistance value or voltage will be changed at the output end. Due to its special structure and function, it is necessary to pay attention to its damage and take regular maintenance during operation.Potentiometers - Basic IntroductionCatalogIntroductionⅠ Potentiometer Using TipsⅡ How to Clean Potentiometer?Ⅲ How to Test Potentiometer?3.1 General Methods3.2 Variable Potentiometer TestⅤ Replacing Potentiometer with 4 StepsⅠ Potentiometer Using Tips1) The resistor body of the potentiometer is mostly made of polycarbonate synthetic resin. Avoid contact with the following items: ammonia, other amines, aqueous alkali solutions, aromatic hydrocarbons, ketones, lipid hydrocarbons, and strong chemicals (excessive acid-base value), etc. Because chemical reaction with those will affect their performance.2) The terminal of the potentiometer should avoid using water-soluble flux when soldering, which will cause metal oxidation and mold material. In addition, avoid using inferior flux, and poor soldering may cause difficulty in soldering, resulting in poor contact or open circuit.3) If the soldering temperature is too high or the soldering time is too long, it may cause damage to the potentiometer terminals. The pin terminal should be soldered at 235℃±5℃ within 3 seconds, and the soldering space should be more than 1.5mm away from the potentiometer body. Do not use solder to hit through the circuit board when soldering, and wire terminal soldering should be soldered at 350℃±10℃ within 3 seconds. Except that, the terminal should avoid heavy pressure, otherwise it is easy to cause poor contact.4) During soldering, the height of the rosin (flux) entering the printing machine board should be adjusted properly, and the flux should be prevented from entering the potentiometer, otherwise it will cause poor contact between the brush and the resistor, resulting in INT, noise and other undesirable phenomena.Potentiometer Structure5) The potentiometer is best used in the voltage adjustment, and the connection method should choose "①" pin grounding. The current adjustment structure should be avoided, because the contact resistance between the resistor and the contact piece will stop the passage of large currents.6) Avoid condensation or water droplets on the surface of the potentiometer, and avoid using it in a humid place to prevent insulation deterioration or short circuit.7) When installing the rotary potentiometer, the strength should not be too tight to avoid damage to the screw teeth or poor rotation. When install the sliding type potentiometer, avoid using too long screws, otherwise it may affects the movement of the sliding handle, and even directly damages the potentiometer body.8) In the process of putting the potentiometer on the knob, the pushing force used should not be too large (not exceeding the parameter index of the pushing and pulling force of the shaft in the specification note), otherwise it may cause damage to the potentiometer.9) The operating force (rotation or sliding) of the potentiometer will become faster as the temperature rises, and slower as the temperature drops. If the potentiometer is used in a low temperature environment, it needs a kind of special low temperature resistant grease.10) The shaft or sliding handle of the potentiometer should be as short as possible when designing it. The shorter the shaft or sliding handle, the better and stable the hand feel. On the contrary, the longer the shaking, the greater the shaking, and the feel is easy to change.11) The power of the carbon film of the potentiometer can withstand the ambient temperature of 70°C, and its function may be lost when the temperature is higher than it.12) The resistor body of the sealed potentiometer is mostly made of polycarbonate synthetic resin. Avoid mixing with ammonia, aromatic hydrocarbons, lipid hydrocarbons, ketones, and strong chemicals (excessive pH), other amines, alkaline aqueous solution, etc, because they will affect its performance.Potentiometer TypesⅡ How to Clean Potentiometer?The potentiometer is to wrap the carbon sheet with POM, PC, ABS and other plastic materials. After assembly, the carbon sheet will not be exposed to the outside, it is not easy to oxidize, and dust is not easy to enter, which protects the potentiometer body.Cleaning Steps of Potentiometer1) Use a screwdriver to carefully open the sealing cover fixing card of the sealing potentiometer, and remove the protective cover.2) Remove the fixed spring card of the rotating shaft and pull out the rotating shaft.3) If some sealed potentiometers cannot take out the shaft, you can directly wipe the carbon film and the metal contacts on the shaft with a cotton ball dipped in pure alcohol.4) Adjust the position and angle of the metal contacts, changing the contact position with the carbon film and increasing the pressure.5) Apply some lubricating oil or special grease on the carbon film to delay the service life.6) Reinstall and fix the metal cover to complete the entire cleaning process. Ⅲ How to Test Potentiometer?3.1 General Methods1) Before detecting the potentiometer by the method of appearance and manual adjustment, firstly observe its appearance. Rotate the knob to check whether the rotation is smooth, whether the switch is flexible, whether the "click" sound is crisp when the switch is turned on and off, and listen to the sound of friction between the internal contact points of the potentiometer and the resistor body, if there is a loud noises indicate that the quality is not good. Normally, the handle should be slightly damped when turning.2) Using the multimeter to measure the potentiometer, you should first select the appropriate ohm gear of the multimeter according to the nominal resistance of the measured potentiometer and then do the measurement. When measuring, touch the red and black test leads of the multimeter to the pins of the fixed pins on both sides, and the multimeter reading should be the nominal resistance of the potentiometer. If the multimeter reading is much different from the nominal resistance value, it indicates that the potentiometer has been damaged.When the nominal resistance of the potentiometer is normal, then measure its changing resistance and whether the movable contact is in good contact with the resistor (fixed contact). At this time, one test lead of a multimeter is connected to the moving contact pin (usually the middle pin), and the other test lead is connected to a certain contact pin (pins on both sides).After connecting the test leads, the multimeter should display zero or the nominal resistance value, and then rotate the multimeter's shaft from one extreme position to the other extreme position, and the resistance value should continuously change from zero (or nominal resistance) to the nominal resistance value (or zero). During the rotation or sliding of the shaft of the potentiometer, if the pointer of the multimeter moves steadily or the displayed indication changes uniformly, it means that the measured potentiometer is in good condition. If the resistance reading of the multimeter fluctuates when the shaft is rotated, it means the movable contact has a fault with poor contact.3.2 Variable Potentiometer Test1) Measure the total resistance at both ends to see if it matches the nominal value.2) Measuring the resistance between a fixed end and the sliding end: rotary the potentiometer to see if the resistance change is continuous. Then measuring the resistances between the other fixed end and the sliding end, if the measured intermediate resistance value changes discontinuously, it indicates that there is a poor contact in the sliding process.PotentiometersⅣ Replacing Potentiometer with 4 StepsThere are many types of potentiometers, and most models cannot be used interchangeably, otherwise the control effect will not be very good. When replacing it, the nominal resistance value should be the same as the damaged variable resistance value or the close to. At the same time, its packages must be considered, otherwise the installation will be difficult. Therefore, we must distinguish between linear potentiometers, exponential potentiometers and logarithmic potentiometers before use. In addition, please note that the precision resistor can only be replaced with a same one when it is damaged, and cannot be replaced with an ordinary variable resistor, otherwise its adjustment accuracy will also be affected.The potentiometer has multiple pins. In order to prevent the wrong pins from being connected during replacement, the following specific operation steps and methods can be used:Step 1: Remove the set screw of the original potentiometer, but do not take off the leads on the potentiometer.Step 2: Install the new potentiometer and fix it.Step 3: Solder a lead on the original potentiometer pin slice, solder it on the corresponding pin slice of the new potentiometer, and the welding method is the same as the old one.Step 4: In the same way, solder each pin wire. Pay attention, welding the next one and then the other one can avoid the wrong position of the leads being welded to each other. Frequently Asked Questions about Potentiometer Uses and Its Replacement1. What is the use of potentiometer?The measuring instrument called a potentiometer is essentially a voltage divider used for measuring electric potential (voltage); the component is an implementation of the same principle, hence its name. Potentiometers are commonly used to control electrical devices such as volume controls on audio equipment. 2. What causes a potentiometer to fail?An electrical short or open will cause the indication to fail at one extreme or the other. If an increase or decrease in the potentiometer resistance occurs, erratic indicated valve position occurs. 3. What does a potentiometer measure?A potentiometer is an instrument which is used for measurement of potential difference across a known resistance or between two terminals of a circuit or network of known characteristics. A potentiometer is also used for comparing the emf of two cells. 4. How do you troubleshoot a potentiometer?Set your ohmmeter to a setting higher than the total resistance of the potentiometer. For example, if your potentiometer is rated at 1,000 ohms, set your ohmmeter to 10,000 ohms. Look at your potentiometer. There should be three tabs sticking out of it. 5. Does a potentiometer need to be grounded?This configuration also acts as a voltage divider and can be used in a number of ways to control a signal. Like any resistor, potentiometers per se do not need to be connected to the ground plane of the circuit, but in the majority of configurations/uses, they will be.

What is Hard Drive?Hard disk, hard disk drive (HDD), hard disk, or fixed disk is the most important storage device of computer. It is composed of one or more aluminum or glass discs. These discs are covered with ferromagnetic material. Your documents, pictures, music, videos, programs, application preferences, and operating system represent digital content all can be stored on a hard drive. Most hard drives are permanently sealed and fixed in the hard drive. Early hard disk storage media was replaceable, but today's hard disk is a fixed storage medium, which is sealed in a case. With the development, removable hard disks have also appeared, and they are becoming more and more popular with different types. In addition, most of the hard disks installed on microcomputers are called Winchester hard drive.Hard DriveTopics Covered in this GuideWhat is Hard Drive?Hard Drive Tech ParametersHard Drive ClassificationsHard Disk StructureHow Does Hard Disk Work?Hard Drive MaintenanceUsing TipsHard Drive FaultsTypes of Hard Disk InterfacesCan a Computer Run without a Hard Drive?Should I Buy SSD or HDD?What the Defferences between HDD and SSD?What is the Lifespan of a Hard Drive?How Much Do Hard Drives Cost?What are the Best Hard Drives?Hard Drive Tech Parameters1) HD CapacityCapacity is the most important parameter of the hard disk. The capacity of the hard disk is measured in megabytes (MB) or gigabytes (GB). However, the hard disk manufacturer usually takes 1G=1000MB in the nominal hard disk capacity, so the capacity we see in the BIOS or when formatting the hard disk will be smaller than the manufacturer’s nominal value.The hard disk capacity index also includes the single-disk capacity. It refers to the capacity of a single disk of a hard disk. The larger the single disk capacity, the lower the unit cost and the shorter the average access time. For users, the capacity of the hard disk is like the computer memory, and it will never be too much.2) Rotational SpeedRotational speed, or spindle speed is the rotation speed of the motor spindle in the hard disk, which is the maximum number of revolutions that the hard disk platter can complete in one minute. It is one of the important parameters indicating the grade of the hard disk. It is one of the key factors that determine the internal transmission rate of the hard disk, and directly affects the speed of the hard disk to a large extent. The faster the rotation speed of the hard disk, the faster the hard disk can find files. The hard disk speed is expressed in revolutions per minute, and the unit is expressed as RPM(revolutions per minute). The larger the RPM value, the faster the internal transfer rate, the shorter the access time, and the better the overall performance of the hard drive.The spindle motor of the HDD makes the platters to rotate at a high speed, generating buoyancy to make the head float above the platters. Bring the sector of the data to be accessed below the head, the faster the speed, the shorter the waiting time. Therefore, the rotational speed largely determines the read speed of the hard disk.The rotation speed of ordinary hard disks for household use is generally 5400rpm and 7200rpm. High-speed hard disks are the first choice for desktop users. For notebook users, it is mainly 4200rpm and 5400rpm. Although some companies have released 7200rpm notebook hard disks, they are still rare in the market. Users have the highest requirements on server for hard disk performance. The speed of SCSI hard disks used in servers is basically 10000rpm, and even 15000rpm. The performance is much higher than that of household products.A higher speed can shorten the average seek time and actual read and write time of the hard disk. However, as the speed of the hard disk continues to increase, it also brings negative effects such as temperature rise, heavy motor spindle wear, and great operating noise. The speed of notebook hard disks is lower than that of desktop hard disks, which is affected to a certain extent by this factor. The internal space of the notebook is small, and the size of the notebook hard disk (2.5 inches) is also designed to be smaller than that of the desktop hard disk (3.5 inches). The temperature rise caused by the increase in speed puts higher requirements on the heat dissipation performance of the notebook itself. In addition, the noise becomes larger, it is necessary to take noise reduction measures, so more technique requirements on the notebook hard disk productions. At the same time, the increase in speed, while the others remain unchanged, means that the power consumption of the motor will increase, the more electricity is consumed per unit time, and the working time of the battery is shortened, so that the portability of the notebook will be affected. Therefore, notebook hard drives generally use a relatively low-speed 4200rpm hard drive.3) Access TimeThe average access time refers to the time required for the head to reach the target track position from the starting position and find the data sector to be read and written on the target track.The average access time reflects the read and write speed of the hard disk, which includes the seek time and waiting time of the hard disk, that is, average access time = average seek time + average waiting time.The average seek time of the hard disk refers to the time required for the head of the hard disk to move to the specified track on the disk surface. This time is of course as small as possible. The average seek time is usually between 8ms and 12ms, while a SCSI HDD should be less than or equal to 8ms.The waiting time of the hard disk, also known as the Latency, refers to the time that the magnetic head is already in the track to be accessed and waiting for the sector to be accessed to rotate below the head. The average waiting time is half of the time required for the disc to rotate one round, and should generally be less than 4ms.4) Data Transfer RateData transfer rate refers to the speed at which the hard disk reads and writes data, in megabytes per second (MB/s). It includes internal data transfer rate and external data transfer rate.The internal transfer rate is also known as the sustained transfer rate, which reflects the performance of the hard disk buffer when it is not in use. The internal transfer rate mainly depends on the rotation speed of the hard disk.The external transfer rate is also called the burst data transfer rate or the interface transfer rate. It is nominally the data transfer rate between the system bus and the hard disk buffer. The type of hard disk interface is related to the size of the hard disk cache.The maximum external transfer rate of the Fast ATA interface HD is 16.6MB/s, while the Ultra ATA interface hard disk reaches 33.3MB/s.The hard disk using SATA (Serial ATA) port is also called serial hard disk. Serial ATA adopts a serial connection method. The serial ATA bus uses an embedded clock signal and has a stronger error correction capability. Compared with the past, its biggest difference is that it can check the transmission instructions (not just data). Errors are found to be automatically corrected, which greatly improves the reliability of data transmission. The serial interface also has the advantages of simple structure and support for hot swapping.5) Cache MemoryCache memory is a memory chip on the hard disk controller with extremely fast access speed. It is a buffer between the internal storage of the hard disk and the external interface. Since the internal data transfer speed of the hard disk is different from the transfer speed of the external interface, the cache plays a role as a buffer among them. The size and speed of the cache is an important factor directly related to the transmission speed of the hard disk, which can greatly improve the overall performance of the hard disk. When the hard disk accesses fragmented data, data needs to be continuously exchanged between the hard disk and the memory. With a large cache, the fragmented data can be temporarily stored in the cache, reducing the load on the external system and improving the data transmission speed. Hard Drive Classifications1) Mechanical Hard Disk (HDD)HDDMechanical hard disk (HDD) is a traditional hard disk, one of the main storage media for computers. It is composed of one or more magnetic discs made of aluminum or glass, magnetic heads, rotating shafts, control motors, head controllers, data converters, interfaces and caches. When working, the head is suspended on a high-speed rotating disc to read and write data. Mechanical hard disk is a computer storage device that integrates precision machinery, microelectronic circuits, and electromagnetic conversion.2) Solid State Drive (SSD)SSDA solid state drive (SSD) is an array storage composed of multiple flash memory chips plus a main control and cache, and belongs to a hard drive made of an array of solid electronic storage chips. Compared with a mechanical hard disk, the read speed is faster and the seek time is shorter, which can speed up the operating system startup speed and the software startup speed.3) Solid State Hybrid Drive (SSHD)SSHDSolid state hybrid drive is a combination of mechanical hard disk and solid-state hard disk. It uses small-capacity flash memory particles to store commonly used files. Disk is the most important storage medium. Flash memory only serves as a buffer to reduce seek time and improve efficiency. Hard Disk StructureThe hard disk is one of the most important storage for computers. Most of the software needed for the computer to function properly is stored on the hard drive. Because the storage capacity of hard disk is large, it is different from computer memory and optical disk. Hard disks are storage devices based on hard rotating disks used on computers. It stores and retrieves digital data on a flat magnetic surface.Take a Look Inside a Hard Drive1) Magnetoresistive Heads (MR heads)The magnetoresistive head is the most expensive part of the hard disk, and it is also the most important and critical part of the HD technology. The traditional magnetic head is an electromagnetic induction magnetic head that combines reading and writing. However, the reading and writing of hard disks are two completely different operations to limit the hard disk design. The MR head uses a separate head structure: the write head still uses the traditional magnetic induction head (MR head cannot write), and the read head uses a new type of MR head. In this way, during the design, the different characteristics of the two can be optimized separately to obtain the best read/write performance. In addition, the MR head gets the signal amplitude through changes in resistance rather than changes in current, so it is very sensitive to signal changes, and the accuracy of reading data is correspondingly improved. Further more, because the read signal amplitude has nothing to do with the track width, the HD track can be made very narrow, thereby increasing the density of the disc. In addition, GMR heads (Giant Magnetoresistive heads) made of materials with a multi-layer structure and better magnetoresistive effect have gradually become popular.2) Magnetic TrackWhen the disk rotates, if the head is held in one position, each head will draw a circular track on the surface of the disk, called tracks. They are invisible to the naked eye at all, because they are only some magnetized areas on the disk surface that are magnetized in a special way, and the information on the disk is stored along such tracks. Adjacent tracks are not close to each other. This is because when the magnetization units are too close, the magnetism will affect each other, and at the same time it will also cause difficulties for the magnetic head to read and write. For example, a 1.44MB 3.5-inch floppy disk has 80 tracks on one side, and the track density on the hard disk is much greater than this value, usually there are thousands of tracks on one side.The surface of the disk is coated with a magnetic medium used for recording, which are magnetic particles under the microscope. The polarity of tiny magnetic particles can be quickly changed by the magnetic head, and can be maintained stably after the change. The system distinguishes 0 or 1 in the binary system through changes in magnetic flux and magnetoresistance. It is precisely because all operations are performed under microscopic conditions, so if the hard disk is operated at high speed while being shocked by external forces, it may cause irreversible data loss due to the head slaps on the surface of the disk. In addition, the uniaxial anisotropy and volume of the magnetic particles will obviously affect the thermal stability of the magnetic particles, and the thermal stability determines the stability of the magnetic particle, that is, the correctness and stability of the stored data. However, it cannot be increased blindly, because it is limited by the write field that the magnetic head can provide and the signal-to-noise ratio of the medium.3) FanEach track on the disk is equally divided into several arc segments, which are the sectors of the disk. Each sector can store 512 bytes of info. The hard disk drive reads and writes data to the disk  from the sectors. 4) CylinderA hard disk is usually composed of a set of overlapping disks. Each disk surface is divided into an equal number of tracks, and numbered from the "0" on the outer edge. The tracks with the same number form a cylinder. The number of cylinders on a disk is equal to the number of tracks on a disk. Since each disk surface has its own head, the number of disk surfaces is equal to the total number of heads. The so-called CHS of the hard disk, namely Cylinder, Head, Sector. So when the number of CHS of the hard disk is known, the capacity of the hard disk can be determined. The capacity of the hard disk is the number of cylinders and the number of sectors. How Does Hard Disk Work?How Do Hard Drives Work?When the hard disk is working, never turn off the power forcibly, which will cause physical damage to the hard disk and data loss. In addition, with high-speed components in the hard disk, if the high-speed disk is shut down forcibly and suddenly, which is more likely to cause damage to the hard disk. So don't turn on the computer immediately after shutting down. This requires time buffering.When the hard disk is working, try to avoid its vibration, because the distance between the magnetic head and the magnetic disk is very close. If it is subjected to severe vibration, the magnetic head will hit the magnetic disk to damage it, which will make the entire hard drive unusable.In the process of using the hard disk, many users compress files to reduce the use of disk space. This will cause the compressed volume file to continue to grow. The data access speed also slowed down, and the number of reads and writes increased, which would affect the heat generation and stability of the hard disk, even reduce service life.  Hard Drive MaintenanceFirst of all, the impact of dust on the hard disk is not small. If dust is attracted to the circuit board, it will cause unstable operation of the hard disk or damage to internal parts. The functional working status of the hard disk has a great relationship with the temperature. Too high or too low temperature will cause the clock frequency of the crystal oscillator to change, which will cause the circuit components to malfunction. In addition, if the temperature is too low, it will cause the air moisture condenses on the component, causing a short circuit.Second, we need to clear your hard drive regularly. This will increase the speed of your hard drive. If there are too many junk files on the hard disk, the speed will slow down and the tracks may be damaged. However, clean up frequently will also reduce the service life of the hard drive.Finally, it is anti-virus. Viruses are the biggest threat to the files stored on the hard drive. Therefore, once we found that the virus should be cleared up in time and try not to format the hard disk. Using Tips1) Don't shut down suddenly while working.When the hard disk starts to work, it is generally in high-speed rotation, if we suddenly turn off the power in the middle, it may cause violent friction between the head and the platter to damage the hard disk. Therefore, it is necessary to avoid this. When shutting down, you must pay attention to whether the hard disk indicator on the panel is still flashing, only the indicator stops flashing and then hard disk read and write ends, you can turn off the computer.2) Prevent dust from entering.Dust can cause great damage to the hard disk. This is because in a severely dusty environment, the hard disk can easily attract dust particles in the air, causing them to accumulate on the internal circuit components of the hard disk for a long time, which will affect the heat of the electronic components, causing the temperature of the circuit components to rise, and resulting in leakage or burnout of the components.In addition, dust may also absorb moisture, corrode the electronic circuits inside the hard disk, and cause some invisible problems. Therefore, although the volume of dust is small, the harm to the hard disk cannot be underestimated. Therefore, it is necessary to maintain environmental sanitation and reduce the humidity and dust content in the air. In addition, users cannot remove the hard disk cover by themselves, otherwise the dust in the air will enter the hard disk and scratch the platters or heads during read and write operations.3) Temperature ControlAs we all known, temperature affects the service life of the hard disk. A certain amount of heat is generated when the hard disk is working, so there is a heat dissipation problem during use. 20～25℃ is better. Temperature can also cause failure of hard disk circuit components, and magnetic media can also cause recording errors due to thermal expansion.On one hand, when the humidity is too high, the surface of the electronic components may absorb a layer of water, oxidizing and corroding the electronic circuits, resulting in poor contact or even short circuits, and it will also cause the magnetic force of the magnetic medium to change, causing data reading and writing errors. On the other hand, it is easy to accumulate a large amount of static charge generated by the rotation of the machine in low temperature, which will burn out the CMOS circuit, attract dust and damage the head and scratch the disk. In addition, try not to make the hard disk close to strong magnetic fields, such as loud speakers, motors, radios, mobile phones, etc., so as to prevent the data recorded on the hard disk from being damaged due to magnetization.Hard Disk Drive StructureHard Drive Faults1) HD Cooling FanConsidering the heat dissipation effect, many people install hard drive cooling fans for their computer hard drives. However, some low-end fans have obvious vibrations and can transmit vibration to the hard drive. In the long term, it will definitely affect the life of the hard drive.2) Optical DriveThe reading speed of mainstream optical drives has reached more than 50 times speed. When the optical disc rotates at a high speed, the vibration of the optical drive itself will drive the resonance of the chassis, which affects the work of the hard disk. And this kind of high-speed rotation generates a lot of heat, because the optical drive is so close to the hard drive, the heat released from the optical drive will surely increase the temperature of the hard drive.3) Static ElectricityIn the process of repairing the computer, many people hold the hard disk with their hands, but in dry weather, tens of thousands of volts of static electricity may accumulate on the hands of people, which may break down the chips on the circuit board, causing the hard disk to malfunction.4) FormattingIf the computer hard disk has bad sectors, many users will take formatting measures. In fact, low format damages the hard disk greatly. It may cause the proliferation of bad sectors on the disk, and even cause the loss of hard disk parameters, making the hard disk unable to use.5) Power SupplyA low-quality computer will cause the hard drive to be disturbed by voltage fluctuations, especially when the hard drive is reading and writing. If there is a problem with the power supply, a hard drive can be scrapped in an instant.6) Magnetic FieldBecause the hard disk is a device that relies on magnetic media to record data, if it is interfered by the magnetic field of the external environment, it is likely to cause the loss of disk data, so you should try to stay away from the magnetic field environment. Types of Hard Disk InterfacesThere are five categories of hard disk interfaces: IDE, SATA, SCSI, SAS, FC1) IDE (Integrated Drive Electronics)IDE refers to the hard disk drive that integrates the controller and the disk body, and is a hard disk transmission interface. There is another name called ATA (advanced technology attachment).2) SATA (Serial ATA)SATA hard disk is called serial hard disk based on its serial data transmission method. In the process of data transmission, the data line and the signal line are used independently, and the transmission clock frequency remains independent. Therefore, compared with the previous PATA, the transmission rate of SATA can reach 30 times that of parallel. It can be said that SATA technology is not an improvement of PATA technology in a simple sense, but a new bus architecture.3) SCSI (Small Computer System Interface)SCSI invention is mainly because the hard disk speed of the original IDE interface is too slow. In fact, SCSI is not designed specifically for hard drives, in fact it is a bus-type interface, working independently of the system bus.4) SAS (Serial Attached SCSI)SAS is serial attached SCSI, which is a new generation of SCSI technology. Like the popular SATA hard disks, it uses serial technology to achieve higher transmission speeds, and improves internal space by shortening the cable. It is a brand new interface developed after the parallel SCSI interface, which is designed to improve the performance, availability, and expandability of the storage system, and provide compatibility with SATA hard drives.SAS interface tech can be backward compatible with SATA. Specifically, the compatibility of the two is mainly reflected in the compatibility of the physical layer and the protocol layer.5) FC (Fibre Channel)Just like the SCIS interface, FC is not an interface technology designed and developed for hard disks at first. It is specially designed for network systems. However, as storage systems require high speed, they are gradually applied to hard disk systems. FC hard disk was developed to improve the speed and flexibility of multi-disk storage system. Its appearance greatly improves the communication speed of multi-disk system, and it uses optical cable connections between systems in a point-to-point (or switching) configuration. There are something to note: the hard disk itself does not have an FC interface, where the cabinet has, which is interconnected with an optical fiber switch. Note: Get more info from Types of Hard Disk Drive Interface.Can a Computer Run without a Hard Drive?A computer can still function without a hard drive. This can be done through a network, USB, CD, or DVD. Computers can be booted over a network, through a USB drive, or even off of a CD or DVD. When you attempt to run a computer without a hard drive, you will often be asked for a boot device. Should I Buy SSD or HDD?1) According to data read and write speedA computer with the same configuration can reach a read and write speed of about 500M/S with a solid state drive, but about 150MB/S with a mechanical hard drive. The difference is nearly three times the speed, which makes the difference in computer response speed even greater.2) According to data security and shock resistanceSince the mechanical hard disk reads and writes data through the magnetic head to read the disk, it is easy to cause data damage due to the collision of the disk and the magnetic head during high-speed rotation, especially it is in the handling process that the disc may be damaged, so everyone needs to be extremely careful when touching it.3) According to weight and volumeCompared with mechanical hard disks, solid state drives are smaller and lighter in appearance, and has stronger performance and faster transfer speed than mechanical hard drives.4) According to noise and heat dissipationSince the solid state drive is made of flash memory particles, it is not equipped with mechanical parts and flash memory chips, and there is no disk and head mechanical motors, fans, etc., so that it can ensure absolute silence. The heat is also very small, and the heat dissipation is also very fast.5) According to power consumptionSSDs commonly use less power and result in longer battery life because data access is much faster and the device is idle more often. With their spinning disks, HDDs require more power when they start up than SSDs. For example, the general full-speed power consumption of a 3.5-inch mechanical hard disk is about 12W, and a 2.5-inch hard disk is only about 5W. The full-speed power consumption of the solid-state drive is about 10W, its working power is generally 2-3W, less than 1W in standby mode.Although solid state drives are definitely faster than mechanical hard drives from above mentioned, but it doesn’t mean that solid state drives are necessarily better than mechanical hard drives, because in terms of price and capacity, mechanical hard drives are "T" is the unit, and most of the solid-state drives are still in G. Although there are also "T", the price is beyond everyone's expectations. One more thing to note is that it is more difficult to restore data if the solid state drive is damaged, while the mechanical hard drive can restore data through repair. Therefore, in terms of data security, mechanical hard drives have more advantages in storing important data. In short, consider comprehensively according to the actual situations. What the Defferences between HDD and SSD?A hard disk drive (HDD) is a traditional storage device that uses mechanical platters and a moving read/write head to access data. A solid state drive (SSD) is a newer, faster type of device that stores data on instantly-accessible memory chips.Generally, SSDs are more durable than HDDs in extreme and harsh environments because they don't have moving parts such as actuator arms. SSDs can withstand accidental drops and other shocks, vibration, extreme temperatures, and magnetic fields better than HDDs.SSDs commonly use less power and result in longer battery life because data access is much faster and the device is idle more often. With their spinning disks, HDDs require more power when they start up than SSDs. However, when not in use, magnetic drives are more reliable for long-term storage than flash memory ones. Thus, HDDs are more capable of long time storage than SSDs when powered off.While normal HDDs can last about 10 years max in reality, and an SSD lifespan has a built-in time of death. To keep it simple: an electric effect results in the fact that data can only be written on a storage cell inside the chips between approximately 3,000 and 100,000 times during its lifetime.As for price, SSDs are more expensive than hard drives in terms of dollar per gigabyte. A 1TB internal 2.5-inch hard drive costs between $40 and $60, but as of this writing, the very cheapest SSDs of the same capacity and form factor start at around $100.With their ruggedness and low energy consumption, SSDs are becoming more popular with portable PCs. With all the advantages that SSD has over HDD, price, availability and capacity are probably the primary factors constraining the acceptance of this new technology. Note: Get more info from SSD vs HDD: Is an SSD Really Necessary?What is the Lifespan of a Hard Drive?Though the average might be three to five years, hard drives can theoretically last much longer (or shorter, for that matter). If a hard drive works 24 hours continuously, it will be damaged in less than 3 years. After normal use, there should be no problem for 5 or 10 years. During use, the garbage must be cleaned regularly and kept HD cool, so as not to get stuck.As with most things, if you take care of your hard drive, it will better last to its potential. How Much Do Hard Drives Cost?A 1TB internal 2.5-inch hard drive costs between $40 and $60, but as of this writing, the very cheapest SSDs of the same capacity and form factor start at around $100. That translates into 4 to 6 cents per gigabyte for the hard drive versus 10 cents per gigabyte for the SSD.According to market trend, the number of hard drives sold each year has declined recently due to the migration of consumer PCs to SSDs, and also demand for higher-capacity HDDs by exascale datacenters. When demand for HDDs spikes, retailers sell out quickly, and prices increase as dealers come into play. What are the Best Hard Drives?Best Hard Drives at a Glance1️⃣Seagate BarraCuda2️⃣Toshiba X3003️⃣WD VelociRaptor4️⃣WD Blue Desktop5️⃣Seagate Firecuda Desktop6️⃣Seagate IronWolf NAS7️⃣Seagate FireCuda Mobile8️⃣WD My Book9️⃣G-Technology G-Drive

CatalogIntroductionⅠWhat is a MAP Sensor ?1.1 The Definition of a MAP Sensor1.2 Abbreviations for MAP sensorsⅡ How does a MAP Sensor Works？Ⅲ  The Application of a MAP Sensor on Vehicles3.1 The Problem Caused of a Faulty MAP Sensor3.2 The Factors of Causing This Fault3.3 How to RepairⅣ 7 Symptoms of a Faulty MAP SensorⅤ Common MAP Sensor Fault CodesⅥ The Difference Between MAP and MAF sensorsⅦ Frequently Asked Questions about MAP SensorsIntroductionFirstly, We need to have a general definition of a sensor. A sensor, in the broadest sense, is a device, module, machine, or subsystem whose purpose is to detect events or changes in its environment and transmit the information to other electronics, most commonly a computer processor. A sensor is always used in conjunction with other electronics.Figure1：The function of  a MAP sensorⅠWhat is a MAP Sensor ?1.1 The Definition of a MAP SensorThe manifold absolute pressure sensor (MAP sensor) is one of the sensors used in the electronic control system of an internal combustion engine.MAP sensors are frequently used in engines that inject fuel. The manifold pressure sensor transmits real-time manifold pressure data to the engine's electronic control unit (ECU). The function of data is to calculate the air density and determine the engine's air mass flow rate, determining the fuel metering required for optimal combustion and influencing the ignition timing advance or retardation. In order to detect intake airflow, fuel-injected engines may use a mass airflow sensor (MAF sensor). Aspirated engines typically use one or the other, whereas forced induction engines typically use both at the same time. The MAF sensor on the intake pipe is connected to the throttle body, and the MAP sensor on the intake port is connected to the pre-turbine.The second variable from IAT (intake air temperature sensor) can be applied to convert MAP sensor data to air quality data. It is referred to as the speed-density method. The engine speed (RPM) is also used to determine the position on the lookup table, which determines the amount of fuel to be added, and thus the speed density (engine speed/air density). The MAP sensor can also be used in OBD II (on-board diagnostics) applications to test the function of the EGR (exhaust gas recirculation) valve, which is a common application in OBD II-equipped general automobile engines.1.2 Abbreviations for MAP sensorsAbbreviations often used are:MAPThere are some other common names of MAP sensors：Manifold Absolute Pressure SensorEngine Load SensorPressure SensorBoost Sensor Ⅱ How does a MAP Sensor Works？ Its operation is based on supplying 5 volts of DC power to the sensor from the PCM (Power System Control Module). Inside the MAP sensor is a resistor that moves in response to the intake manifold pressure. The resistor alters the voltage between 1V and 4.5V (depending on engine load), and the voltage signal returns to the PCM to indicate manifold pressure (vacuum). This signal is required by the PCM to determine fuel delivery and is occasionally used to determine whether the EGR valve is functioning properly. The Manifold Pressure Sensor is useful for diagnostics because it measures throttle performance, turbo performance, and leaks in the inlet manifold. Due to its position, it should always read negative pressure unless the turbocharger is boosting pressure. This is depicted in the diagram below. Ⅲ The Application of a MAP Sensor on vehiclesA computer and a series of sensors in modern vehicles control the engine's fuel consumption and other operations. While you may never have to work on any of these sensors, one, in particular, is critical to the smooth operation of an engine — the MAP (manifold absolute pressure) sensor. What exactly is a MAP sensor and what does it do? When your engine runs strangely, it could be due to a MAP sensor failure, so let's take a look at what the MAP sensor does.Figure2: the application on vehicles  3.1 The Problem Caused of a Faulty MAP SensorA faulty MAP sensor can cause a variety of performance issues in your vehicle. If the sensor is faulty, reading too high, the fuel management system may use more fuel than necessary, reducing fuel economy. If the MAP sensor reads too low, the onboard computer will reduce the amount of fuel it believes is required and starve the engine, causing it to run erratically and produce less power. In either case, if the sensor is not properly reading, your vehicle will fail emissions testing. When you connect a diagnostic code reader, you may discover trouble codes P0068, P0069, P1106, or P1107. 3.2 The Factors of Causing This FaultA MAP sensor failure can be caused by several factors. The sensor's operation is dependent on both electronic and mechanical components. A vacuum chamber within the sensor allows the sensor to detect changes in manifold pressure. A leak in the vacuum chamber can develop over time, rendering the sensor unable to read correctly. Years of extreme temperature fluctuations and vibration can also wreak havoc on the internal circuitry due to the sensor's location in the harsh engine compartment environment. Another source of failure is dirt or other contamination that prevents the sensor from physically accessing the intake manifold air flow. 3.3 How to RepairThe difficulty of replacing a bad MAP sensor varies depending on the vehicle. It is typically bolted or screwed to the outside of the intake manifold or throttle body. Unplug the sensor wire, then unscrew the screws and carefully remove the faulty sensor. Simply reinstall the screws and plug the wire back in to get your new one up and running. Depending on the vehicle and whether or not a trouble code was set, resetting the check engine light may necessitate the use of a diagnostic tool.Many people are perplexed when they learn that they have a faulty sensor and wonder, "What is a MAP sensor?" While its function is straightforward, it has been critical to obtaining good fuel economy and performance from your vehicle's engine for many years. If you suspect a MAP sensor failure, your neighborhood NAPA Auto Care center can handle the problem and get you back on the road. Ⅳ 7 Symptoms of a Faulty MAP Sensor 1. Poor Fuel Economy.If the ECM detects low or no vacuum, it assumes the engine is under load and dumps more fuel, and advances the spark timing. This results in excessive fuel consumption, poor fuel economy, and, in extreme cases, detonation. 2. Lack of Power.When the ECM perceives a high vacuum, it assumes that the engine load is low and reduces fuel injection, and retards spark timing. On the one hand, fuel consumption will be cut down, which appears to be a good thing. However, if not enough fuel is consumed, the engine may lack acceleration and passing power. 3.Failed Emissions InspectionWhen the ECM perceives a high vacuum, it assumes that the engine load is low and reduces fuel injection, and retards spark timing. On the one hand, fuel consumption will be cut down, which appears to be a good thing. However, if not enough fuel is consumed, the engine may lack acceleration and passing power. 4. Rough Idle.Inadequate fuel injection deprives the engine of fuel, resulting in rough idling and possibly random cylinder misfiring. 5. Hard Starting.Similarly, an excessively rich or lean mixture makes it difficult to start the engine. You most likely have a MAP sensor problem if you can only start the engine when your foot is on the accelerator. 6. Hesitation or Stalling.Stepping on the gas may not be fun when starting from a stop or attempting a passing maneuver, especially if the ECM is displaying a lean mixture based on faulty MAP sensor readings. 7. Check Engine Light.MAP sensor diagnostic trouble codes (DTC) can range from a simple circuit or sensor faults to correlation or range faults, depending on the age of your vehicle. A dead MAP sensor will not read anything, whereas a failing MAP sensor may send data to the ECM that is illogical, such as low engine vacuum when the throttle position sensor (TPS) and crankshaft position sensor (CKP) both show the engine at idle.Figure3: check dash board light Ⅴ Common MAP Sensor Fault CodesThe following codes are associated with the MAP sensor and should be looked for if your check engine light has illuminated:  P0068: MAP/MAF - Throttle Position CorrelationP0069: Manifold Absolute Pressure - Barometric Pressure CorrelationP0105: MAP Circuit MalfunctionP0106: MAP/Barometric Pressure Circuit Range/Performance ProblemP0107: Manifold Absolute Pressure Figure4: one of the faulty code  Ⅵ The Difference Between MAP and MAF sensorsThe intake manifold pressure sensor is the full name of the map manifold absolute pressure sensor, and the computer uses the speed increase pressure change to adjust the speed. The following conclusions are for reference only.MAF is an air flow sensor with the full name Mass air flow meter. Figure5: the MAF sensor  The first thing I mentioned was the MAP formula, which is MAP+Manifold vacuum = Barometric Sensor. The function of the Barometric Sensor.It indicates the height of the car's altitude, allowing the length of the fuel injection to be determined when the car is cold.In general, there are two variables: the manifold vacuum and the barometric. The manifold vacuum changes with speed, while the barometric is almost constant, unless you're in the sky. 1, Manifold vacuum Full throttle (WOT) = 0 hgidle 18-22 hg2, MAp should be equal to baro in the case of KOEO (manifold vacuum is 0 hg)3, KOEO 3v-4vKOER will drop to about 1v as the vacuum increases4, 5v reference nap throttleFigure6: 5v reference nap throttle  5, KOEO 150 hz KOER will be lower than this in the future6, Reference value sunnyvale 150hz/ 30HG denver 123 hz7, if egr is stuck slightly open, map will also report an error8, The duty cycle and counts of iac will also decrease,9, stft -9% at idle accelerating jumps to lean change map. There is no absolute value, and the calibration of each car manufacturer is not the same MAF-air flow sensor, simple and rude, directly tells the computer how much flow.1, idle 0.5-1v2, egr&tps follow3, If there is another baro (calculate or extra), the method is the same as map, 30 hg4, maf is dirty, will undereportting, cause too much air to enter, fuel trim is too thin5, down side: If there is turbulence in one of the intake and exhaust, the problem cannot be determined6, maf gs/s = liter (known Toyota, Ford.)7, baro relearn( 80% tps with low rpm)Figure7: baro relearn Ⅶ Frequently Asked Questions about MAP Sensors1. Can I drive my car with a bad MAP sensor?It is not advisable to drive your vehicle with the MAP (manifold absolute pressure) sensor disconnected. ... With the MAP sensor disconnected, the fuel delivery will be excessive and could cause harm to the engine and exhaust system (catalytic converters). 2. Will a MAP sensor cause a misfire?Your engine misfires and shakes: If a MAP sensor reports a false high pressure reading, the engine's computer will signal for more fuel. This results in a rich mixture, which can foul the spark plugs and cause a cylinder not to fire. A misfiring engine will shake and transmit that motion into the cabin of the vehicle. 3. Can you clean a MAP sensor?Use an electric parts cleaner on a soft rag or paper towel to clean the outside of the MAP sensor. ... Shake out the excess and let the MAP sensor dry. Check the MAP sensor vacuum hose or intake manifold port for additional contamination. Clean these with electric parts cleaner and a brush if necessary. 4. How much is a MAP sensor?The MAP sensor usually sits in an easy to reach area, on or near the intake manifold. The sensor itself will cost you anywhere from $30 to $200, depending on your vehicle and if you use OEM or aftermarket parts. 5. Can I use alcohol to clean MAP sensor?Clean the outer surface of the MAP sensor using electric parts cleaner. ... Spray the alcohol liberally over the MAF sensor. Be sure to cover the MAF sensor's wires, intake and all its crevasses to thoroughly clean the part. Do not touch or scrub the MAF sensor's wires because they are very delicate and could break. 

What is Breadboard?When learning how to build a circuit, the breadboard is one of the most basic parts. There are many small jacks on the breadboard, which are specially designed and manufactured for solderless experiments of electronic circuits. A breadboard consists of plastic block holding a matrix of electrical sockets of a size suitable for gripping thin connecting wire, component wires or the pins of transistors and integrated circuits (ICs). The sockets are connected inside the board, usually in rows of five sockets. Since various electronic components can be inserted or pulled out at will according to needs, welding is eliminated, circuit assembly time is saved, and components can be reused, so it is very suitable for the assembly, debugging and training of electronic circuits.What is Breadboard?Topics Covered in this GuideWhat is Breadboard?Why are breadboards called breadboards?How Breadboard Looks like?IC & DIPHow to Use Breadboards?Types of BreadboardsBasic Principles of Breadboard WiringBreadboard Using Tips for BeginnersMaintenance of the BreadboardsWhich Breadboard is Best?What are the Holes in the Breadboard Called?Is a Breadboard Necessary?How much Voltage can a Breadboard Handle?How Does Current Flow in a Breadboard?How Many Amps Can a Breadboard Take?Why are breadboards called breadboards?The name of the breadboard can be traced back to the era of vacuum tube circuits. At that time, most of the circuit components were large in size. People usually fixed them on a wooden board for cutting bread with screws and nails for connection. Later, the circuit components became more and more smaller, but the name of the breadboard is still used. The breadboard most commonly used today is usually made of white plastic and is a pluggable (solderless) breadboard. It was designed by Ronald J. Portugal in 1971.It is a process of verifying ideas by creating an initial model. If you are not sure how a circuit will react normally under a given parameter setting, it is best to build a prototype to test it. For those who are new to electronic circuits, the breadboard is a good start. The advantage of a breadboard is that it can hold the simplest and most complex circuits at the same time. If your circuit cannot be accommodated by the current breadboard, you can splice other boards to adapt to all circuits of different sizes and complexity. Such as integrated circuits (ICs). When you try to master how a module works and need to rewire multiple times, you certainly don't want to solder the circuit interface every time. Once you find a problem, you can disassemble each part to prepare for some troubleshooting. How Breadboard Looks like?The shape of the breadboard is mostly cuboid, with different sizes. The breadboard generally has two layers, the top is a grid shape with double-sided tape adhering to it( you can tore it to fix the breadboard in a certain position). The upper layer of the breadboard is composed of a grid of rows and columns, and there is no conduction between rows.The whole board is made of thermosetting phenolic resin, and there are metal strips at the bottom of the board. Holes are punched at the corresponding positions on the board so that the components can be in contact with the metal strips when inserted into the board, so as to achieve the purpose of conducting electricity. Generally, every 5 orifice plates are connected by a metal strip. There are two rows of vertical jacks on both sides of the board, also a group of 5. These two sets of jacks are used to provide power to the components on the board.Breadboard Layout ExampleSome breadboards have two columns on the left and right sides. These two columns are customarily used as the positive and negative poles of the power supply (This is not necessarily true, depending on your own usage habits and circuit needs). Each of the five grids in the same column of the two columns is a group, which is conductive. But there is no conduction between columns. Then in the middle part, every five columns of grids form a group, and the five grids in this group are conductive. There is generally a groove in the center of the board, which is designed for the needs of integrated circuit (IC) and chip testing, and is used to separate the left and right parts of a board. Some breadboards do not have two columns on the left and right sides due to the size, but the other structures are the same.The motherboard uses a glass fiber board with a conductive layer of copper foil, which is used to fix the solderless breadboard and lead out the power terminal.There may be slight differences in the structure between different breadboards, but they are basically the same. IC & DIPAn unique feature of the breadboard is: Integrated Circuit (IC) and Dual in-line Package (DIP)Dual in-line Package (DIP) Chip：MA2053Do you see the small gap in the middle of the breadboard? There is a reason for this gap, the use of integrated circuits. There are ICs in almost every electronic device. They run motors, regulate voltage, act as timers, perform logic tasks, and perform almost everything you need to perform.ICs can have different numbers of pins, sizes and functions. However, many ICs are suitable for a standard called dual in-line packaging (DIP), which means they all share a set width. As you guessed, the width fits the gap in the middle of the breadboard. This makes it easier to use the IC without having to worry about connecting the wrong pins together. the holes of the breadboard are spaced 0.1” (2.54mm) apart in both the X and Y direction which is the spacing used for adjacent DIP IC leads as well as many other components such as headers.IC & DIP Example on Breadboard How to Use Breadboards?You can use breadboard to make quick electrical connections between components- like resistors, LEDs, capacitors, etc, so that you can test your circuit before permanently soldering it together. Without welding and manual wiring, the circuit and components can be tested by inserting the component into the hole, which is convenient to use. Before use, determine which component's pins should be connected together, and then insert them into the same group of 5 small holes.How to Use a Breadboard?Example: LED Lighting1) MaterialsOne breadboard, several connecting wires (the connecting wires should use needle-shaped wires at both ends), one led light, and one 3V button battery.2) First, put the battery into the battery holder (this can be bought online), and plug it into the breadboard. Then, insert the battery holder into the left and right parts of the breadboard. Parts are separated by grooves to avoid short circuit between the positive and negative poles of the power supply).3) Lead two wires from the positive and negative poles of the battery, and then plug the LED into any two grids that are not conductive on the breadboard (the long pin of the led is positive and the short pin is negative), and finally connect the wires from the positive and negative poles of the battery to the two LED segments.Types of Breadboards1) Solderless BreadboardA solderless breadboard is a motherboard that does not serve as a base, and does not have a soldering power socket to draw out but can expand a single breadboard. Connect the two poles of the power supply to the sockets on both sides of the breadboard, and then you can plug in the components for experiment (the power supply should be disconnected during the process of inserting the components). When more than 5 components or a set of jacks cannot be inserted, you need to connect multiple sets of jacks with a breadboard cable.The advantages of solderless breadboards are small size and easy to carry, but the disadvantages are relatively simple, inconvenient power connection, and small area. It is not suitable for large-scale circuit experiments. If you want to use it for large-scale circuit experiments, you need to fix multiple breadboards on a large wooden board with screws, and then connect them with wires.2) Single BreadboardA single breadboard is a part with a motherboard as a base and a dedicated terminal for power access, and even some breadboards that can perform high-voltage experiments include ground terminals. This kind of board is more convenient to use, that is, directly connect the power supply to the terminal, and then insert the components for experiment (the power supply should be disconnected during the process of inserting the components) when more than 5 components or a set of jacks cannot be inserted, you need to use breadboard cables to connect multiple sets of jacks.The advantage of a single breadboard is that it is small in size, easy to carry, and can easily switch on and off the power supply, but it has a small area and is not suitable for large-scale circuit experiments.3) Composite breadboardComposite breadboard is a board composed of many solderless breadboards. Generally, 2-4 solderless breadboards are fixed on the motherboard, and then the power cords of each board are connected together with the copper foil in the motherboard. The kind of breadboards is also specially designed for different circuit units to control the power supply, so that each board can carry different voltages according to the needs. The use of the composite breadboard is the same as the single breadboard.The advantage of the composite breadboard is that it can conveniently switch on and off the power supply, has a large area to carry out large-scale experiments, and is highly mobile, and has a wide range of uses. However, it is large and heavy for carrying, so it is suitable for laboratories and electronic hobbyists use. Basic Principles of Breadboard WiringComplete the circuit overlap on the breadboard, different people have different styles. However, no matter what style or habit, the following basic principles must be paid attention to when completing the circuit overlap:1. The fewer connection points, the better.Each additional connection point actually increases the probability of failure artificially. There are common faults such as impassability in the breadboard hole, loose wire, and broken wire inside.2. Try to avoid overpasses.The so-called "overpass" means that components or wires ride on other components or wires. Beginner is easy to make such mistakes. It will bring trouble to the replacement of components in the later stage. On the other hand, in the event of a failure, the messy wires can easily make people lose confidence.3. Try to be as reliable as possible.There are two phenomena that need attention:① Breadboard integrated circuits are easy to loosen. Therefore, for integrated circuits such as operational amplifiers, it is necessary to press down forcefully. Once it is not reliable, the position needs to be changed.② The pins of some components on the breadboard are too thin, so please be careful to move them slightly. If you find that they are not secure, you need to change the position.Electronic BreadboardBreadboard Using Tips for Beginners1. When installing discrete components, it should be easy to see their polarity and signs. After placing the component pins, bend them where needed. In order to prevent the exposed leads from short-circuiting, a wire with a sleeve must be used, and the component pins are generally not cut to facilitate repeated use. Generally, do not insert components with a pin diameter> 0.8mm, so as not to damage the elasticity of the contact piece inside the socket.2. The pins of integrated circuits that have been used many times must be repaired neatly, the pins cannot be bent, and all the pins should be slightly skewed outward, so that the lead angles and the jacks can be reliably contacted. The arrangement of the components on the breadboard should be determined according to the circuit diagram in order to facilitate the wiring. In order to be able to correctly route and facilitate wire checking, the insertion direction of all ICs must be kept the same, and which cannot be inserted upside down for the convenience of temporary wiring or to shorten the length of the wire.3. According to the sequence of the signal flow, the method of installation and debugging is adopted. After the components are installed, first connect the power cord and the ground wire. In order to check the line conveniently, try to use different colors for the line. For example, the positive power supply generally uses a red wire, the negative power supply uses the blue, the ground wire uses the black, and the signal wire uses the yellow. Other colors can also be selected according to the real conditions.4. The breadboard should use a single-strand wire with a diameter of about 0.6mm. Cut the wire according to the distance of the wire and the length of the jack. The wire end is required to be cut into a 45º, and the stripped length of the wire end is about 6mm. All the wires are required to be inserted into the bottom plate to ensure good contact. In addition, bare wires should not be exposed to prevent disconnection with other wires.5. The connection is required to be tightly attached to the breadboard to avoid collision and ejection of the breadboard, resulting in poor contact. The wiring must pass around the integrated circuit, and it is not allowed to cross the integrated circuit, and the wires must not be overlapped with each other, try to be horizontal and vertical. This is conducive to line wiring and checking, and components replacement.6. It is best to connect a capacitor with a capacity of tens of microfarads in parallel between the input terminal of each power supply and the ground, so as to reduce the impact of current during transients. In order to suppress the high-frequency components in the power supply, a high-frequency decoupling capacitor should be connected in parallel at both ends of the capacitor, generally 0.01~0.047Uf.7. During the wiring process, it is required to place the various components on the corresponding position on the breadboard and mark the pin numbers used on the circuit diagram to ensure the smooth progress of debugging and troubleshooting.8. All ground wires must be connected together to form a common reference point. Maintenance of the BreadboardsUsing a breadboard is more convenient than using a soldering method, easy to replace wires and components, and can be used multiple times. However, the breadboard should be maintained during daily use. In the multiple use of the breadboard, the spring sheet will become loose and the elasticity will become poor, which is easy to cause poor contact and virtual welding. They are difficult to find out.The breadboard that has been used many times should be uncovered from the back, and the spring sheet with poor elasticity should be taken out, repaired and then inserted into the original position. This can enhance the elasticity and increase the reliability and service life of the breadboard. In addition, pay attention to where the breadboard is used. Large-volume, high-quality or high-power components cannot be plugged into the breadboard because the breadboard jacks are small and the leads of such large components are relatively thick. At this time, the components can only be placed outside the board. Use a single strand of hard wire to solder to the lead, and then insert it into the breadboard.Breadboards are not suitable for high-frequency circuits, because the lead inductance and distributed capacitance of the breadboard are relatively large, which has a great impact on the performance of high-frequency circuits. Breadboard is suitable for integrated circuits, especially for digital integrated circuits, because digital integrated circuits usually have low operating frequency and low power, and they use fewer RC components. It is more difficult for discrete component circuits to use breadboards, especially for circuits with high frequency and high power. Which Breadboard is Best?Best Breadboard Kit ReviewsELEGOO Upgraded Electronics Fun KitREXQualis Electronics Component Fun KitElegoo EL-CP-003 3 MB-102 830-pin solderless PCB board kitFreenove Solderless Breadboard Ultimate Starter KitKeywishbot Electronic Component BreadboardREXQualis Solderless BreadboardKuman GPIO expansion kit for Raspberry PieBoot 3 400-point solderless circuit breadboardPaxcoo 4 breadboard kits with 120 jumper wires for ArduinoSmraza Basic Starter KitSunFounder breadboard kit RAB holderTEKTRUM Solderless plug-in breadboard kitMicrotivity IB401 400-point experiment breadboardElenco 9440 breadboard with 350 jumper wire set kitMakeronics Breadboard + Electronics Fun Kit What are the Holes in the Breadboard Called?Breadboards are designed to work with through-hole electronic components. They have many tiny sockets (called 'holes') arranged on a 0.1" grid. The leads of most components can be pushed straight into the holes. ICs are inserted across the central gap with their notch or dot to the left.The holes in the top-most rail are highlighted in orange and the holes in the bottom-most one are highlighted in green. In the central area of the board are vertical lines of five holes that are electrically connected. These lines of five holes are known as nodes. Is a Breadboard Necessary?Although a breadboard is essential to prototype circuits without having to solder them together and when you have verified that the circuits works you can solder it onto a perfboard. But note that breadboards are never necessary. A properly-milled and constructed panel should generally stay flat under normal conditions, so the only time I add a breadboard end is if I think the design benefits from it visually.In addition, high frequency (above 10MHz) Where the additional breadboard capacitance would present problems (oscillators, etc) Where glitches due to poor wire connections would result in poor operation. Where most of the parts are not through hole 0.1" (2.54mm) centers. How much Voltage can a Breadboard Handle?Breadboards are mostly used for low voltage and current applications, however, breadboards can handle 12 volts. Breadboards are made by different manufacturers, so the voltages they can handle depends on how they are constructed. How Does Current Flow in a Breadboard?The vertical columns of the breadboard are called terminals, while the horizontal long rows are called power rails because they are mostly used to connect the power supply to the breadboard. The positive rails are indicated by red lines, while the negative rails are indicated by black ones. That means our electric current, which is made up of moving charges, flows out of the positive side of the battery, through the wire and into the breadboard power bus. It then flows out of the black wire and into the second power bus, through the power bus and back to the negative side of the battery. How Many Amps Can a Breadboard Take?Due to the temporary nature of the contacts, most breadboard has a current limit of one amp or less. Breadboard generally cannot handle frequencies greater than ten megahertz because of the nature of the contacts, which create a stray capacitance of around two to twenty picofarads (pFs) for every connection.

CatalogⅠ What is a Ballast Resistor ?Ⅱ Types of Ballast Resistors2.1 Fixed Resistors2.2 Self-Variable ResistorsⅢ The Working Principle of  Ballast ResistorsⅣ Ballast Resistor – Uses and Applications4.1 Ballast Resistor in Fluorescent Lamps4.2 Ballast Resistor for Automotive Applications4.3 Ballast Resistor in a LED CircuitⅤ Symptons of Failture Ballast-ResistorⅥ Frequently Asked Questions about Ballast resistors Introduction  “Ballast” is generally considered as “something that provides stability in English dictionary.  ” Thus, when we refer to an electrical ballast, we are referring to an electrical device that is important in maintaining the stability of the electrical circuit. However, you might be wondering how it provides stability. Depending on the circuit in which they are used, some electric ballasts limit current while others limit voltage. By doing so, they reduce the risk of overvoltage or overcurrent in the circuit, thereby improving system stability. The complexity of electric ballast varies greatly. It can be as simple as a resistor, capacitor, inductor, or a combination of these, or as complex as the electronic ballast found in fluorescent lamps.  Ⅰ What is a Ballast Resistor ? A ballast resistor is an electronic component that is usually used to regulate the current in a circuit. Some devices, such as fluorescent lamps, can exhibit negative resistance characteristics, and an increase in current will result in a decrease in voltage. Negative resistance can cause damage to the power supply or equipment. Ballast resistors are usually connected in series with the negative load, taking advantage of the fact that all components in the series circuit receive the same current. Some ballasts are just series resistors, while others use capacitors and more complex components. Figure1: complex components Ⅱ Types of Ballast ResistorsA resistor is a current-limiting electronic component that can reduce circuit voltage and current. Ballast resistors are classified into three types: fixed, variable, and reactive.2.1 Fixed ResistorsThis genre of ballast resistors have a fixed resistance. A high resistance value is primarily taken considered for most applications. This genre of ballast resistor is commonly used in simple circuits with low-powered loads such as neon or LED lamps. This fixed resistor is also applied to control the ventilation fan speed. It employs a fixed ballast resistor with two center taps. The fan speed selector switch detours portions of the ballast. Therefore, the entire ballast resistor is suitable for full speed, while no section of the ballast resistor is suitable for the low speed.2.2 Self-Variable ResistorsThese ballast resistors have the property of resistance in response to changes in current, such as an increase in current increasing resistance and a decrease in current decreasing resistance. Incandescent lamps frequently use these ballast resistors. As the current through the lamp increases, the ballast resistor heats up, and the resistance rises with the temperature, as does the voltage drop across the resistor. When the current is down, the temperature of the ballast resistor decreases as well, as does its resistance and thus the voltage drop. The benefits of using this type of ballast resistor are that it provides more precise current control than a suitable fixed resistor. Another benefit is that the power lost in the resistive ballast is decreased because a smaller section of the overall power is lost in the ballast when compared to a fixed resistor. Ⅲ The Working Principle of  Ballast Resistors When 220V 50HZ AC power is applied to the switch closed circuit, the current flows through the ballast, and the lamp filament starter heats the filament（The starter was turned off in the beginning. The gas arc discharge in the jumping bubble in the starter caused the bimetallic sheet to heat and deform due to the application of an AC voltage greater than 190V, and the two electrodes were close together to form the filament heated by the passage.) Because there is no arc discharge when the two electrodes of the starter are close together, the bimetal cools and the two poles separate. As the ballast is inductive, when the circuit is suddenly interrupted, 600V is generated at both ends of the lamp for about 1ms. The pulse voltage is -1500V; the exact voltage value depends on the type of lamp. When the lamp discharges, the voltage at both ends drops immediately. At this point, the ballast limits the lamp current on the one hand while also supplying power on the other. There is a phase difference of 55° to 65° between the voltage and the working current of the lamp in order to keep the secondary starting voltage of the lamp stable.Figure2:  the working principle of  a ballast resistor Due to its simple structure, inductive ballast, as the first type of ballast to work with fluorescent lamps, has a relatively large market share. However, on account of its low power factor, poor low-voltage startup performance, heavy energy consumption, stroboscopic and many other shortcomings , its market is gradually being replaced by electronic ballasts. The energy consumption of inductive ballasts: 40W (lamp tube power) + 10W (inductive ballast self-heating consumption) is equal to the total power 50W consumption of the whole set of lamps and lanterns. An electronic ballast is a converter that converts low frequency alternating current power to high frequency alternating current power. Its basic operation is as follows: after passing through a radio frequency interference (RFI) filter, full-wave rectification, and a passive (or active) power factor corrector (PPFC or APFC), the industrial frequency power supply becomes a DC power supply. The output of high-frequency AC power of 20K-100KHZ is added to the LC series resonant circuit connected to the lamp via the DC/AC converter to heat the filament, but the lamp is "discharged" into the "on" state and then enters the light-emitting state. At this point, the high-frequency inductor limits the current increase, ensuring that the lamp tube receives the voltage and current required for normal operation. Various protection circuits, such as abnormal protection, surge voltage, and current protection, temperature protection, and so on, are frequently constructed to improve reliability. Ⅳ Ballast Resistor – Uses and Applications Ballast resistors are most commonly used to adjust the current to a negative resistance load. They can also be applied in other contexts. Fixed ballast resistors are common in low-power devices like light-emitting diodes (LEDs) and neon lights. LEDs are a positive resistive load that can benefit from ballast resistors. 4.1 Ballast Resistor in Fluorescent Lamps Fluorescent lighting, as we all know, is a popular and efficient lighting system. However, there is a disadvantage to using this type of lighting system. When directly connected to a voltage source, it heats up very quickly. This situation is due to the lamp's uncontrollable current draw as soon as its operation. A ballast resistor, connected in series with the lamp, is applied to the circuit to prevent overheating caused by excessive current draw. Therefore, the function of ballast resistor is to regulates the current and reduces the voltage. However,  for the lamp to light up, an arc has to be formed between its two electrodes. This necessitates a high starting voltage that is nearly equal to the supply voltage. The ballast resistor provides the required voltage during startup, and then immediately after an arc is established, it reduces the voltage while also regulating the current flow. Figure3: application in fluorescent lamp 4.2 Ballast Resistor for Automotive Applications Ballast resistors are generally included in the ignition kits of automotive machines such as automobile engines. Such devices are often called Ignition Ballast Resistors because of their application. The application of this device reduces the possibility of coil failure. It is connected between the ignition coil's primary voltage source and the coil stud. This connection helps to reduce the coil voltage and coil current, so the coil does not get as hot as it would without it, extending the coil's life. However, a high voltage equal to the primary voltage source is required to start the ignition engine. As a result, a jumper wire is frequently connected to the ballast resistor. This jumper wire provides the voltage required to start the engine.  Figure4: application in automotives 4.3 Ballast Resistor in a LED Circuit If the source voltage in an LED circuit is greater than the rated voltage of an LED lamp, the LED may be damaged. It is strongly advised to connect a ballast resistor in series with the lamp to avoid this case. By connecting the ballast resistor in this manner, the voltage across the LED is down to a tolerable level. The circuit diagram for the same is shown in the figure below.  Figure5: application in leds  The following formula is the value of resistance of the ballast :R = (E – Vf)/IFWhere: R= resistance of the ballast resistorE = voltage sourceVf = forward voltage of the LEDIF =Forward current of the LED. So, let's say you have an LED with a voltage rating of 4 volts, a forward current of 10 mA, and a voltage source of 6 volts. This means that the voltage across the LED should be 4 or less than 4 volts. As a result, the resistance of the ballast resistor should be R= (6-4)/0.010 = 200 or greater. Now that we've covered the applications briefly, let's look at the different types of ballast resistors on the market. Ⅴ Symptons of Failture Ballast-Resistor A ballast resistor is a device in your car that limits the amount of current flowing through an electric circuit. Because they did not have the benefit of circuit boards like most modern vehicles, ballast resistors are commonly found in older vehicles. Normal wear and tear can damage the ballast resistor over time, so there are a few things to look for if you suspect a bad or failing ballast resistor needs servicing. 1. Vehicle starts, then immediately goes out The most obvious symptom is that the vehicle starts but then dies as soon as you remove the key. If this occurs, Your Mechanic's experts will be able to measure the voltage coming from the ballast resistor and determine if it needs to be replaced. They will inform you of the condition of your ballast resistor once they have read the voltage. 2. Not starting at all The vehicle will not start if the ballast resistor is not functioning properly. Because it is an electrical system, it is best left to the professionals. The only way to get the vehicle running again is to replace the ballast resistor. 3.  Don’t jump the resistor Some people attempt to jump the resistor, which means that the ballast resistor is ignored and the extra current is routed to the points. The points are not designed to withstand the additional voltage, causing them to wear out and fail prematurely. This will result in a much more extensive repair than if the ballast resistor was replaced at the start. Furthermore, because you are tampering with electricity, it can be dangerous, especially if you don't know what you're doing. 4.  Let the vehicle beIf your ballast resistor is out of work, your vehicle will not start and you will need to have it towed to a mechanic's shop. Because the professionals at Your Mechanic make house calls, you will be able to save money on towing. Furthermore, because the vehicle will not start, it is not a dangerous situation as long as you leave it alone. Do not attempt to bypass the ballast resistor and do not continue to try to start the engine. Allow the professionals to repair it so you can get back on your way. Ⅵ Frequently Asked Questions about Ballast resistors 1. Is a ballast resistor necessary?　If the coil required a ballast resistor when it was used with points, then you must still use the resistor. If it didn't, then no resistor is necessary. The ballast resistor keeps the engine running by preventing the engine from receiving full amperage from the ignition once started.　 2. Why do ignition coils need ballast resistor?　In simple terms, the ballast resistor in a Mopar limits the amperage, or current flow, through the coil while the engine is running, thereby extending the life of the coil and breaker points of the distributor. 3. How do you know if a ballast resistor is bad?To test your ballast resistor you need an ohm meter or multimeter set to ohms. Remove the connectors from both sides of the resistor. The ohms should read between 1.8 and 5 ohms. You should be getting 9 volts to the positive side of the coil. 4. What causes a ballast resistor to fail?The resistance through the ballast resistor varies with current flow which varies with engine rpm. This naturally causes the resistor to expand and contract from heat. That's why they eventually fail. 5. Can a resistor wire go bad?　　The only way the wire will "go bad" is if it gets a break in it so it has infinite resistance (an open circuit). 6. Which circuit the ballast resistor is used?　　Ballasts can also be used simply to limit the current in an ordinary, positive-resistance circuit. Prior to the advent of solid-state ignition, automobile ignition systems commonly included a ballast resistor to regulate the voltage applied to the ignition system. 7. What is inside of a ballast?　A magnetic ballast (also called a choke) contains a coil of copper wire. The magnetic field produced by the wire traps most of the current so only the right amount gets through to the fluorescent light. That amount can fluctuate depending on the thickness and length of the copper wire. 8. What's the difference between a ballast and non ballast coil? Basically, a non-ballast coil is designed to produce full spark output with 12 volts on the input (+ terminal). A ballast coil is designed to produce the same spark output, but with only 6 to 9 volts on the input.