Commonly used electronic component basic knowledge

A resistor（R）
Referred to as a resistor, means having a certain technical performance of the circuit of the secondary from the resistance effect element, can be used to adjust the current in the circuit and the voltage, or as a circuit in the load.
1, The resistance of the parameters:
a And resistance: refers to the resistance value of size.0Ω—Hundreds ofMΩ
b, Dissipation power: refers to the resistance of the long-term work can withstand（consume the most power.
2, The resistance of the material:
Resistance to commonly used materials are carbon film, metal film, metal oxide film, wire-wound, cement ceramic line around the semiconductor and other materials.
3Resistor type:
① Fixed resistance:Refers to the resistance value of the fixed resistor
② Trim resistance:Refers to the resistance value can be fine-tuned resistance
③ Adjustable resistance:Commonly known as potentiometer, refers to the resistance value of a continuously adjustable resistor
④ Thermal resistance:Refer to the resistor value as the temperature changes the resistance of the
a, A positive temperature coefficient thermistor: refers to the resistance value with temperature increases the resistance（PTC）
b, A negative temperature coefficient thermistor: refers to the resistance value with increasing temperature decreases the resistance of the
⑤ The pressure-sensitive resistance:Refers to the resistance value as the voltage varies the resistance.
⑥ Humidity resistance:Refer to the resistor value as the temperature changes the resistance of the
⑦ Photosensitive resistance:Refer to the resistor value as the temperature changes the resistance of the
⑧ The resistance of the power notation:General power rate3WMore than a resistor are the resistance of the housing marked its power value, such as:3W, the5W, the7W, the10W, the20W, the30W, Etc., and small power3WThe following is part of the indicated power, such as:3W, the2W, the1W, Etc., and does not indicate the power is more for the power1WThe following low-power resistor, for actual use, the available power maximum resistance instead of the small power resistor, otherwise it can not instead of, if not know the resistance power of the size, in practice the available resistance of the volume of the same or slightly larger instead.
5, A resistor represents method:
① Directly indicate the resistance value and a unit, such as:1.5 Ω , the160Ω , the1Ω Etc.
② Directly indicate the resistance value and the units“Ω ”Omitted, such as:100I.e.100Ω , the1 I.e.1Ω , the22MI.e.22MΩit.
③ With a fewXA few make a few fewΩ Such as:4Ω7, the9Ω1Is9.1 Ω , the8M2I.e.8.2 MΩ Etc.
Some with a fewRA few representative points a fewΩ ,As:1R5I.e.1.5 Ω , the3R9I.e.3.9 Ω Etc.
④ Resistance value behind the other letters of the alphabet such asJ, theK, theMOr Roman numerals （ ⅰ ,ⅱ,ⅲ, or plus or minus a few percent, such as:±5%, the±10%, the±20%Of the resistance the error level.
⑤ Digital representation method, the sheet resistance and the portion of the trim resistor and a potentiometer using this method
With three digits, the first and Second Bit represents a valid number, and the third indicates the number of times the multiplier1For101 , the2For 102 , the3For 103 , the4For104 and......8For 108 , But9For 100 The effective number is multiplied by the multiplier times that the resistance value. （Unit：Ω）

6, Color ring resistance
Use colored ring represents the resistance and the error of the resistance called color ring resistance
① Four-color ring resistanceFor ordinary resistance, the application of the maximum
First, two-color ring represents a valid number, the first three-color ring represents multiplier times, the first four-color ring represents the error, and note: the color rings and more for gold, silver or other color ring far more the effective multiplied by the number of times the multiplier, that is, the resistance of the resistor values in units ofΩ ）
▲Since the resistance value of a manufacturing error, Multimeter with measurement error, the human eye also has an error, so use a multimeter to measure the resistance value when there is a certain error is allowed, error in or less are considered normal.
▲With high blocking（RX10KOr1KGear test large resistance（dozensKΩAbove the resistor, and the resulting readings are significantly smaller measurement error increases.
▲For four-color ring resistance: the front then paint the ring represents a valid number, that is, the resistance value of the first two, and the multiplier times is the resistance factor, so the first two bits of the color Ring of the effective number of photos reading and writing it down, and then multiplied by the multiplier times that its resistance value.
▲The exercises can be put-color ring resistor according to the color ring reading out, and then use a multimeter to resistance profile of the test, if the test value and the read out value is substantially the same error, then you see the color of the ring is substantially accurate, if the measurement value and the read value of the phase difference is too large, it may be some color ring color wrong, it should be re-tested to be seen again, until accurate so far.
▲The resistance is small with low resistance shift（X10OrX1Test and resistance elements with high resistance shift（X10KOrX1KTest, the resistance is not greater than not less medium, can be used in the Resistance gear such as:X1K, theX100, theX10Other test, but the needle refers to the close to the scale to the left position, in this case, is not only easy to see the readings and readings are the most accurate.
▲Fast readout of the four-color ring resistance

② Five-color ring resistanceFor precision resistors, used in Instrumentation or demanding circuit in use
The first, second, and third color the ring is a valid number, the first four-color ring denotes times the multiplier, the fifth color of the ring represents the error（note：the color ring and more for gold, silver or away from the other color ring far some of the effective number multiplied by the multiplier times is the resistance（unit:Ω ）
7, A resistor of good or bad judgment
① For ordinary fixed resistor with a multimeter resistance profile test its resistance value should the resistor's nominal value, i.e. the resistance marked on the Resistance base is the same as error < ±20%Is normal. If the resistance difference is too large, i.e. the error is > ±20%Is the resistor has the value of the variable that is larger or smaller, to the resistance becomes large majority, and the resistance becomes small, the rare and cannot be used, if the resistance becomes infinite（∞）then the resistor has an open circuit is damaged, if the resistance becomes zero rare, then the resistor has short-circuit damage.
② For fine-tuning the resistance, also called fine-tuning potentiometer and adjustable resistor called a potentiometer with a multimeter resistance profile test which both ends of the resistance value shall be its nominal value is substantially the same error < ±20%As normal, otherwise the potentiometer is bad or damaged. While testing the potentiometer center of the head in the middle pin with either end of the resistance between the value should be in the zero to nominal value continuously between can be adjusted to normal, otherwise the potentiometer is bad or damaged.
③ For the positive temperature coefficient thermistor（PTCThat at room temperature the resistance value should be a few decades or so is normal, if the resistance value is too large, the internal connection is bad, if the resistance is infinite, it has open-circuit damage, if the resistance value is substantially zero, the short-circuit damage, while the resistance of the ohmic heating when its resistance will become as big a few hundredKΩ The above is normal.
④ For the negative temperature coefficient of the thermistor at room temperature and tested for its resistance value shall be its nominal value substantially the same as the error is normal. If the resistance value of the difference is too large, then the resistor is bad or damaged, if the resistance value becomes infinite, then the resistor has an open circuit damage. Meanwhile, the resistance the higher the temperature the greater the resistance is small, and the temperature the lower the resistance becomes more significant to normal. Otherwise, the negative temperature coefficient thermistor is bad or damaged.
⑤ For the pressure-sensitive resistor, due to its operating voltage is high tensVAbove it with a multimeter resistance profile of the test when the resistance value should be infinite maximum normal because of the table within the battery voltage is low or the pressure-sensitive resistor is bad or damaged, the pressure-sensitive resistor at a rated voltage or less, the resistance are great for Infinity, only large or exceed its rated voltage when the resistance is only the steady play is reduced.
⑥ The humidity sensitive resistor, in air-dry condition test its resistance value should be reduced dozens ofKΩAbout; and when there is no strong light irradiation when the resistance becomes smaller dozensΩThe following is normal. Otherwise, the photosensitive resistor is bad or damaged.
8, The resistance of the fault and repair
① For filmSuch as carbon film, metal film and other material fixed resistor, if the damage cannot be repaired, only to be replaced to solve it.
② For wire-wound resistorOccurred the open-circuit fault, this time for the resistance of the wire in a position to burn off cause, may be off at the welding after a good can also continue to use, if it is cement wire wound）resistance, then open the Shell to find burnt off at and repaired, and then with cement package dry can be used, Of course, the best trade-in solutions as well.
③ For trim resistorEasily because of the use of the middle of the sliding contact and the carbon film due to oxidation and poor contact failure, this time with the potentiometer of the cleaning agent cleaning solution, the cleaning of the void can only be replaced to solve it.
④ For potentiometer, Prone to carbon film wear and the intermediate slide sheet（Center-tap）poor contact failure, then adjust the center of the slide sheet and the carbon film between the location or with a potentiometer cleaning agent solution.
⑤ For positive temperature coefficient thermistor（PTC, The most prone to resistance with the pressure of the sheet between the poor contact of the fault, then the adjustable pressure plate and cleaning to repair, if the resistance of the body has been broken, it can not be repaired, only replaced.
⑥ For the negative temperature coefficient thermistor, If the damage cannot be repaired only replaced.
⑦ For the pressure-sensitive resistor and photoresistor, If the damage cannot be repaired only replaced.
⑧ For moisture sensitive resistanceIf the damage is generally only the replacement of the solution, and it is difficult to fix, but for a video recorder, a camera（DVSuch as moisture sensitive resistance damage and no device replacement, in case of emergency you can use a2KOhm about fixed resistor substitution to solve, this time will lose moisture detection function.
Second, the capacitor
Referred to as capacitor, made of two pieces or two sets of balanced metal plate in the middle layer of the dielectric（insulating layer constituted, is a charge storage device, with the charge and discharge characteristics.
1, Capacitance, dielectric material
Common air, ceramic, Mica, polyester, polypropylene, aluminum, silver, etc., the electrolyte dielectric material.
2, the The capacitance of the main electrical parameters
① Capacity:Refers to the charge storage capacity of the size of the amount.
The capacity of the basic unit is the Farad, abbreviated as actF, The commonly used units of mV ActmF, The micro-methoduFAnd Ng law na lawnF, The Pico Act that skin ActpFEtc.
② Pressure:Refers to the capacitance of the long-term work can withstand voltage withstand voltage: a fewV--A fewKV
3, Capacitance type
① Fixed non-polar capacitors
Refers to the capacitance of the fixed polarity of the capacitor, such as: ceramic ceramic dielectric）capacitors, Mica capacitors, film capacitors such as polyester, polypropylene, capacitor）
② Fine-tune（polar）capacitance
Refers to the amount of capacitance can be adjusted to the non-polar capacitor. Note: the trimmer capacitor is no capacitance on. Such as: air ceramic, film and other fine-tuning capacitor.
③ Adjustable capacitance
Refers to the capacitance of continuously adjustable variable of a non-polar capacitor note: the tunable capacitors are non-polar capacitor）。 Such as: Air, Film, etc. adjustable capacitor. Common are single-link, dual-link, four-link with adjustable（variable）capacitance.
④ Electrolytic capacitor
Refers to the use of aluminum, tantalum, niobium and other electrolyte as the dielectric of a capacitor is known as electrolytic capacitors, electrolytic capacitors, most of them are polar capacitors.
Note: electrolytic capacitors no fine-tuning with adjustable structure, all of the fixed capacity of the capacitor.
4, Capacitance withstand voltage notation
① Directly, the indicated pressure values and unitsit. Such as:6V, the25V, the50V, the100VEtc.
Note: electrolytic capacitors are generally using this method, the other capacitor is generally less available

② Directly, the indicated pressure value and the unit（V）Omitted. Such as:25I.e.25V, the63I.e.63V, the100I.e.100VEtc.
③ Use the numbers and Alphabet diagram pressure valueBy a digit and a letter, the digital representation of the pressure-resistant10The times multiplier, Alphabet shows the pressure resistance of the effective number, the active number multiplied by the multiplier times is the capacitance of the pressure value.
Note: polyester capacitor using this method is more common, the other capacitor application of this method is less）
Example: 1A=10V 2A=100V 2B=125V
2C=160V 3D=2KV 3G=4KV
1E=25V 2F=315V 4W=45KV
④ Use color to represent the pressure-resistant
Part of the ceramic dielectric capacitors have a color to indicate its resistance to the pressure value, i.e. the outer of different colors to represent different pressure
⑤ Some of the imported ceramic dielectric（ceramic）capacitanceIn the capacity below draw a horizontal line for the pressure-resistant50VNot draw horizontal line for the pressure-resistant500Vit.

⑥ Some of the capacitance of the pressure unitsWVShowsVSuch as:50WVI.e.50V, the350WVI.e.350VEtc.
⑦ Those who did not use the above method to indicate the pressure value of the, The capacitor can be considered to be pressure-resistant25VOr below the low-voltage capacitor.
5 And the capacity of the capacitor represents the method
① Directly indicate the capacity of the numerical value and the unitSuch as:5PF, the33PF, the100PF, the22nf, the0.01 uF, the47uF, the22FEtc.
Note: an electrolytic capacitor is most used in this law
② Directly indicate the capacity of the numerical, And the unit ofu, then, thepShowsuF, thenF, thepFSuch as:47uI.e.47Ufit.
③ With a fewXA few representative points a fewXSuch as:8P2I.e.8.2 Pf, the6n8I.e.6.8 Nf, the4u7I.e.4.7 uFEtc.
④ All capacitance valuesWith a few tenths or a few well-behaved to represent and are not marked units. Its capacity value in units of tenths of auFSuch as:0.01I.e.0.01 uFEtc.
⑤ Capacitance value as an integer and does not indicate the units ofit. Its unit isPFNote: the three-digit last digit is not zero, except for the. Such as:3About3PF, the15I.e.15PF, the120I.e.120PFEtc.
⑥ Digital representation: With three-bit digital representation of note: the last bit is zero, with the exception of the first, second digit represents a valid number, the third digit represents the times the multiplier1For 101 , the2For102 , the3For 103 ...... 8For 108 , But9But for 100 The effective multiplied by the number of times the multiplier, is the capacitance, in units ofPFit.
⑦ Color ring color bar represents the law
With the color ring resistance notation is the same, but the unit isPF
⑧ Manufacturers capacitor capacity units with the uppercase EnglishMDFOrMFRepresentativeuFit. Such as:25MDFI.e.25uF, the100MFI.e.100uFit.
⑨ Some capacitance in the capacitance value of the back marked with the letter or plus or minus a few percent for the representation of the capacitance of the error level.
Note: most manufacturers, the capacitance of the error level using the above letters to represent, but there are also individual manufacturers use other letters or characters to represent the error level in this one move out.
6, The polarity of the electrolytic capacitor polarity distinction
① Not cut foot aluminum electrolytic capacitor, the long leg is positive and the short of the foot end is negative.
② A polarity of the capacitor in the factory are required to indicate the positive and negative can be positive and negative pole marked, it can only indicate the positive or negative terminal can be from the capacitance of the housing directly seen.
③ Use a multimeter to resistance profile test is positive and negative（for reference only） with a multimeter resistance profile of the highest range of the shift（RX1KOr10KGear test the polarity of the electrolytic capacitor forward and reverse leakage resistance, i.e. the insulation resistance is big, and the reverse leakage is large, i.e. the insulation resistance of the features. When the test when the needle is first to the right, swing the greater the capacity of the needle swing is also bigger, and then slowly to the left to return to. If the needle can return to Infinity large scale on the left of the starting position, then the capacitance substantially no leakage, if the hands cannot be returned to the Infinity position in a scale to stop, at this time the resistance value of the leakage resistance, i.e. the insulation resistance of the repeatedly tested many times, which should be transposed table pen test out its forward and reverse leakage（insulation resistance）。 Any leakage is small, i.e. the insulation resistance of a the black pen is connected to the electrode of the electrolytic capacitor is the positive electrode and the red pen is connected to the negative electrode, otherwise the pen polar opposite.
Note: the black pen then the electrolytic capacitor of the positive electrode and the red pen then negative test forward leakage resistance.
The red pen is connected to the electrolytic capacitor anode and the black pen then the positive test negative to the leakage resistance.
7, Capacitance withstand voltage test
Capacitor pressure resistance can be from the capacitance of the outer seen directly without testing, but if there is a pressure table can also be used to pressure the table directly test it out.
8, Capacitance, capacity test
① For eligible capacitor, the capacity of the capacitor housing flag value, generally can be directly seen to without testing.
② If the capacitor table, part of the digital multimeter can also test the capacitor capacity, but can only test a small capacitance not measured large capacitance capacities. You can use the capacitance meter directly test the capacitor capacity.
③ Part of the pointer multimeter in series to a certain voltage value of the alternating current case also can measure the capacitor capacity, but the error is large, does not promote the use of it.
④ With ordinary mechanical pointer multimeter can also be a rough testing out the capacity of the capacitor size, the method is to use a multimeter to the resistance profile（small capacity to use a high-impedance gear, while the capacity of the pillars with low blocking it. Exchange table pen test multiple times, the capacitance, the greater the hands of the swing amplitude is larger, and the capacity of the smaller hands of the swing amplitude is smaller, according to the needle swings to the size of its standard capacity capacitor comparison, you can estimate the capacitance of the capacity size of the note: in General the use of the capacity of the capacitor without requiring particularly precise, the capacitance only in a certain range can be used normally. Under normal circumstances use only the ordinary multimeter when the capacitance is roughly the test centre.
Note: when the capacity of the largest high blocking test, the needle will hit the Super tick is difficult to compare the size, then we reduced-scale test to the needle does not hit the ultra-scale is limited, in order to compare the capacity size.
▲Capacity is too small-less than0.01 uFIt has the highest blocking tests are quasi to see the needle swing is normal,For these capacitors it is difficult to use a resistance profile compared its capacity size,Using only a capacitor table test.
▲If the test when the needle points to zero ohms at the stop and can not return to,At this time the capacitor has short-circuit damage,And not to test its capacity.
9, Capacitance, capacitive reactance
Refers to the capacitance on the AC equivalent resistance is called the capacitive reactance.
10, Capacitance characteristics
Having the General high-frequency resistance of the low-frequency through the AC resistance DC characteristics.
a)The capacitance of use
Can be used for filtering, coupling, decoupling, bypass, tuning, resonance, and other purposes.
b)The capacitor is good or bad judgment
Use a multimeter to determine the resistance profile（capacity is small be sure to use a high impedance profile and the capacity of the largest available low-impedance Gear test capacitor should be transposed table Pen Test repeatedly or turn the capacitor short-circuit discharge after testing the capacity of the large hands of the swing amplitude is greater, and the hands of the swing should be slowly returned to normal that is the only way the capacitor is the better one. If with the same capacity, good capacitance comparison in the test table swing amplitude is too small to work simply do not swing the capacitance has changed little or failure damage, while the hands of the swing should slowly return to the small capacity of the return speed and large capacity the return speed of the slower one. To return to a position of the hands stop at this time the resistance of the capacitor leakage resistance. This leakage resistance the bigger the better preferably to infinity, this leakage resistance is too small, the capacitor leakage is too large and poor performance, this leakage resistance is substantially zero, i.e. the needle on the scale of zero to Europe to stop, then the capacitor has short circuit breakdown damage it. For smaller-capacity capacitor with a resistor gear of the highest profile are difficult to see the needle swing is normal. But if the capacitor has electric leakage or breakdown of the short-circuit phenomenon you might test out note: for this type of capacitor has electric leakage or breakdown of MU can be considered that the capacitor has poor performance or damage and not use
① For content greater than1uFThe non-polar capacitor with a multimeter resistance profile of theRX1KOr10KGear test should be able to clearly see the needle to the right swing after a rewind back to the Infinity position is normal. If you can not return to the Infinity position of the capacitors have leakage phenomenon and it is best not to use it, if the leakage resistance is substantially zero, the capacitor has the breakdown of the short-circuit damage.
② For a capacity of more than0.01 uF(10uF)And less than1uFThe non-polar capacitors,With the resistance profile of the highest range(Best useRX10KProfile,WithX1KShift some capacitance difficult to observe)Profile,The test should be able to see the hands a micro-swing(That the needle swing is very small)After a rewind back to the Infinity position for normal,And can not have leakage or short circuit phenomenon,Otherwise, the capacitor is bad or damaged.
③ For the capacity of less than0.01 uF(10nFI.e.10000pF)The non-polar capacitors,Use a multimeter to resistance profile of the highest range(As:The test is difficult to see the needle swing(Because the capacity is too small,Table pen just contact capacitance when the capacitor is fully charged and the hands had a chance to swing)Is normal. If you suspect that these capacitance becomes small or failure of the damage, you can only capacitance meters test or in the practical application of the substitution method substitution method is used in a good place of the suspected corrupt the judgment, of these capacitive absolute in the test there can be leakage power short circuit, otherwise it can be considered that the capacitor has been damaged and can not continue to use.
④ For the polarity of the electrolytic capacitor, because the capacity is large, so the test can be based on capacity size to select the appropriate gear range to be tested, namely, small capacity with high-grade and capacity of the large low-grade, such as:10uFThe following can be usedX10KOrX1KGear,100uFLeft and right availableX1KOrX100 Gear,1000uFThe following can be usedX100Or1000uFMore availableRX10Or, more gear selection for the reference test should be greater the capacity of the needle swing greater. With the shift position-scale comparison and hands after the swing should slowly return to normal. Hands return to a scale position stop and cannot be returned to Infinity, i.e. the hands of the scale starting position, it indicates that the capacitor has a leakage, the leakage is smaller, i.e. the leakage resistance is large, the better, if the leakage is too large, i.e. the leakage resistance, the smaller is the capacitance of the poor performance, if the leakage resistance is substantially zero, then the capacitor has breakdown. At the same time due to the electrolytic capacitor has a positive leakage is small, i.e. the leakage resistance, and reverse leakage, i.e. the leakage resistance of the features. It is a test of the General forward leakage is small, and the reverse leakage size may not be considered, as well as for polar electrolytic capacitor, if the storage time is too long which leakage also become large, as long as the use of a period of time to even test many times its leakage is also reduced.
III. Inductor
Referred to as the inductor, commonly known as the coil is determined by the coil winding with the inductive effect of the elements.
1． Inductor type
① Air-core inductance: refers to coils wound on a hollow bracket or directly around the system inductance.
② The magnetic core inductance: refers to the coil wound on the magnetic core, i.e. the coil inside the magnetic cores formed.
③ Copper core inductor: refers to coils wound around the copper core of the inductor.
④ Iron core inductor: refers to coils wound on the core of the inductor.
⑤ With a tap of the inductor: refers to the coil on the extracted one or more taps of the inductor.
2． Inductance
Refer to the inductor capacity the size of the amount, called the inductance. Inductance is the basic unit for Henry, referred to as Heng（H, The commonly used units are millihenry（mHThat microhenries（µHEtc.
1H=103 mH=106μH
3． Inductance（XL）
Refers to the inductance of the AC barrier effect that is the equivalent resistance is.XL=2лfL
4． Inductance characteristics
Having through the DC resistance of the exchange, the General low-frequency resistance of the high-frequency characteristics.
5． Inductor of self-inductance effect
When through the inductor coil current is changed, the coil will generate a self-induced electromotive force to hinder the change in current, and this effect is called an inductor of self-inductance effect.
6． Inductance mutual inductance effect
The two close to each other in the coil, when one changes the current through another will also induces an induced electromotive force,This effect is called the inductance the mutual inductance effect. The transformer is based on mutual inductance principle made.
7.The inductance of use
Can be used for filtering, impedance wave, current limiting, transformation, tuning, damping effect.
8． The inductance of the representation
① Directly indicate the inductance value and the units.Such as:10mH , the150μHit.
② With a fewXA few representative points a fewXit.Such as:1H2I.e.1.2 H, the3m3I.e.3.3 mH, the8μ2I.e.8.2 µHit.
③ With a color circle or color the dot notation: With a four-color ring color dots to represent, the first two-color ring color of the points represents a valid number, the first three-color ring color points indicate times the multiplier, and the fourth color ring represents error. With four-color ring resistor represents a method of the same
Gray red brown gold that is82X101±5%
④ With the number of turns（the number of turns of said
Some of the inductance of the coil does not indicate its inductance and directly indicate the inductance of the coil should be wound laps（the number of turns, such as: the3TI.e.3Circle turns, and19TI.e.19Turns, etc.
⑤ There are a lot of inductance of the coil is composed of manufacturers to develop, thereon neither inductance also does not indicate the winding number of turns, in practice, only with the same coil replacement or according to the original specifications weight around.
9． Inductance（coil）the quality of the judgment
Use a multimeter to resistance profile can be rough tests the inductance of the coil is good or bad, is to test the coil at both ends of the DC resistance and the normal value comparison or the same as the coil if the resistance value is substantially the same error≤±10%It can be considered that the coil is good, if resistance value of the difference is too large then the coil is bad, if the resistance value becomes infinite then the coil has an open circuit is damaged, if the resistance value becomes zero, the coil has short-circuit damage.
10． The inductance of the coil fault and maintenance
① The inductance of the coil in the event of a short circuit or partial short circuit fault when the coil is open according to the original specifications of the rewind can be repaired.
② The inductance of the coil if an internal poor contact or open circuit fault can carefully disassemble the coil check poor contact at the multi-coil joints or off the road at the re-welding to repair, can also be according to the original specifications with a new line of rewinding to fix.
③ In most cases, if the inductance of the coil when there is a fault if there is a new spare parts in the case of the recommended replacement solution, if no new spare parts only to repair it.
IV. Transformer
Transformer is a way to transform AC voltage, current and impedance of the multi-coil device.
1.The transformer is converting AC voltage and current and the impedance of the relationship:
N1, theN2Respectively for the primary and secondary number of turns; andU1, theU2Respectively, for primary and secondary voltage;I1, theI2Respectively, for the initial current;Z1, theZ2Respectively, for the initial stage of the impedance. The primary coil（N1Also called the primary coil; a secondary coil（N2Also called secondary coil.
Transformer primary and secondary turns ratio is with the primary and secondary voltage is proportional to the initial-stage Current is inversely proportional to the initial level of the impedance of the square root is proportional. Expressed by the formula:
2.Transformer type
① High frequency transformer:Means for converting high-frequency electrical signal of the transformer. As the antenna coil, and the oscillation transformer.
② Intermediate frequency transformer:As in weeks: refers to a superheterodyne radio receiver used to change quite electrical transformer.
③ Low frequency transformer:Means for converting low-frequency electrical signals to the transformer, such as the audio transformer.
④ Power supply transformer:Means for converting the AC mains transformer.
⑤ The self-coupled transformer:Refer to the primary and secondary coils may be shared transformer.
3． The transformer of good or bad judgment
Use a multimeter to resistance profile can be roughly determined the transformer of good or bad, the method is to measure the transformer each coil's DC resistance and the normal value or good of the transformer, if all the coil resistance is normal, it can be considered that the transformer is good; if there are one or more of the coil is bad or damaged. While testing different coil, or between the coil and the iron core between the insulation resistance should be infinite greatly properly, otherwise the transformer is bad or corrupt.
4． Transformer failure and repair
① The transformer primary winding connected in series with a temperature fuse of the transformer, if the primary is open, the more this temperature the fuse blows, the cause, you can replace a temperature fuse solve, if not the fuse, replace the case also can short-circuit this insurance to solve.
② For General transformer, if the coil is damaged, you can press the primary coil of the parameters of the rewind can be repaired.
③ In most cases the transformer damage difficult to repair or restoration project is too large then it is recommended to change the resolution.
5． The transformer parameters and the calculated
① Core cross-sectional areaSto:S=Tongue width×Stacked thick
② Core cross-sectional areaSWith the transformer powerPThe relationship:S=1.25
③ Per volt laps（Nto:Refers to the each volts should be wound coil number of turns（turn number
fAC frequencySFor the core cross-sectional area,BmaxIs the magnetic flux density
④ Primary laps（N1With the secondary number of turns（N2）
N1=U1N（U1For the primary voltage; andN2=U2N（U2Is the secondary voltage
⑤ Wire diameter（d: It refers to the winding of the coil wire diametermmit.
IFor the wire currentI=P/U）
Primary wire diameterd1=; Secondary wire diameter
V. Semiconductor crystals diode（D）
Referred to as a diode is a two-layer structure of a semiconductor device, by aPNThe junction of the composition, having a one-way conductive properties.
1． PNJunction
① PType semiconductor:Refers to the hole most of the carriers in the impurity semiconductor.
② NType semiconductor:Refers to electrons as majority carriers in the impurity semiconductor.
③ PNResults:ThePType semiconductor andNType semiconductor Composite, in which the interface is formed at the space charge region, i.e. the barrier layer is calledPNJunction.
④ PNThe junction characteristics:Having a unidirectional conductive properties.
2． The diode of the main electrical parameters
① Forward current:Correction wizard to pass the time allowed by the electrical maximum current.
② Reverse breakdown voltage:Refer toPNJunction reverse breakdown of electricity high voltage, that is, the diode voltage.
③ Forward voltage:Correction wizard on the desired voltage. Germanium materialsPNKnot: the0.2 V(0.2—0.3 V);Silicon materialsPNKnot: the0.6 V(0.5—0.7 V);Compound material2VAbout(1—3V)it.
④ Junction capacitance:Refer toPNJunction capacitance formed is called the junction capacitance.
3． Diode applications
Can be used for the rectifier, regulator, switch, damping, tuning and other purposes.
4． Diode polarity determination
① For General diodes, logo, such as color ring to one end of the negative electrode and the other end to the positive electrode.
② For light emitting diode, if not cut foot cases the long leg is positive, the short leg is the negative electrode.
③ For the diode, the most it can from its internal structure directly seen its positive and negative pole.
④ Use a multimeter to resistance profile determined: with a multimeter resistance profile of the test diode in the forward and reverse resistance, according to diodePNThe knot has a forward resistance reverse resistance characteristics to judge. Test a small resistance a black pen is connected to the positive electrode, and the red pen then the IS the negative electrode.
5． Diode（PNKnot of good or bad judgment
Use a multimeter to resistance profile of the test diode in the forward and reverse resistance of the diode（PNThe knot is to the resistance as small as possible, the reverse resistance the bigger the better. If the diode in the forward and reverse resistance is very small or very large then this tube is the breakdown of the short-circuit or open-circuit damage.
VI. Semiconductor crystals transistor
The transistor is a kind of signal with amplification and switching the role of the three-layer structure of a semiconductor device, consisting of twoPNJunction components.
1． Transistor configuration
The transistor is divided intoPNPType andNPNType the two types of structure.
EOreThe representative of the emitter,BOrbRepresents the base,COrcThe representative of the Collector,BCKnot（bcKnot: the Collector junction
BEKnot（be Knot: the emitter junction
2． The transistor is the main electrical parameters
①PCMto:Refers to the collector of the maximum power dissipation, that is, the transistor's maximum power.PCMof < 1WFor small power tube;PCM＞1WFor high-power tube;PCM= a1WThe left and right of the power tube.
②ICMto:Refers to the collector of the maximum current, that is, the transistor's maximum current.
③Bvceoto:Refers to the base open collector and the emitter of the maximum reverse breakdown voltage, that is, the transistor resistance to pressure.
④Iceo to:Refers to the base open collector and emitter maximum reverse leakage current, that is, the transistor of the penetration current.
⑤fTto:Refers to the characteristic frequency, i.e., refers to its emitter amplifier circuit in the magnification down to1When the frequency.
fT≤3MHzFor low-frequency tube;fT＞3MHzFor high-frequency tube;fT> A few hundredMHzKnown as ultra high frequency tube
⑥hFEto:Refer to the transistor of the DC amplification factor of the DC magnification）
hFE=（IcIs the collector current,IBIs the base current
⑦βValue:Refer to the transistor AC magnification
（ΔICIs the collector current change amountΔIBIs the base current change amount

3．PNPType withNPNDistinction
Use a multimeter to resistance profile of the test transistor of the foot between the forward and reverse resistance, where once the red pen then fixed one of the electrodes is, black pen are connected to the rest of the two electrode resistance are relatively small, then this tube is forPNPTube asPTube, and the red pen then the electrode to the base; if anything that once black pen then fixed one of the electrodes, the red pen are connected to the rest of the two electrode resistance are relatively small, then this tube is forNPNTube asNTube, and the black pen is connected to the base.
4． The transistor of the three electrodes to distinguish
According to the above method to determine thePNPWithNPNTube and find out the base, the rest of the two electrodes can be used the following method to determine the method is to: a multimeter set resistance profile of theRX1KThe shift, the red-black table pen are connected to the remaining two electrodes, if it isPNP- Tube is in the red pen is connected to the electrode and between the base and connected to a100KAbout the resistance of the resistor with your finger instead of the table if there are significant changes, then the red pen then the electrode is a collector, and the black pen is connected to the electrode of the emitter; if the tube isNPN- Tube test pen polarity is just the opposite, the test method andPNP- Tube exactly the same.
5． Transistor amplifying action principle
The base current has a tiny change, the collector current will have a larger change, i.e., with a small current to control a large current in order to achieve current amplification, which is the transistor amplifying action principle.
6． The transistor is good or bad judgment
With a multimeter, resistance profile of the test transistor twoPNKnot（emitter junction and collector junction, i.e.,beJunction andbcThe junction of the forward resistance of the smaller withRx1KGear test amount of a fewKEurope around the better, and the reverse resistance is greater withRx1KGear test for dozens ofKEuro or more, and most of the tube is infinitely large, the better, if one or bothPNJunction forward resistance is too large, such asRx1KGear test dozens of Europe more or reverse the resistance is too small, such asRx1KShift test is less than dozensKEurope is the tube poor performance, if one or bothPNThe junction of the forward and reverse resistance is very small, such as a substantially zero, or very large, such as fundamental to Infinity is the tube due to two or onePNJunction breakdown or open-circuit damage. While the collector and the emitter analysis between the positive and negative resistance becomes large, the best is infinite, but some of the tube in the tens ofKEurope above the notch, the better. If this resistance is too small then the tube to penetrate the current is too large and poor performance, if this resistance is substantially zero then the tube set is made between the breakdown, as well as withHFEGear measurement or resistance profile to estimate the transistor of the amplifying abilityHFEValue, the tube type to the different uses which enlarge the capacity is different, but shall have the zoom capabilityHFEThe value should be more than a few times, but did not enlarge the capacity of the tube is not available.）
7． Transistor failure and repair
① ． Transistor performance is bad or damaged, it is not for the transistor to be trimmed and the only trade-in or a good transistor to solve it.
② ． The transistor is damaged, it should be possible to select with the same type of tube replacement. If not the same type of tube, it should be used in the performance parameters of the same or similar tube.
③ Chosen generation with a pipe, its parametersIcm, thePcm, theBvceoAnd other parameters should be equal to or greater than the prototype of the number of tubes can be replaced.
④ The low-frequency tube only in the low-frequency circuit applications, and the high frequency tube can not only in the high-frequency circuit applications and can be used in low-frequency circuit applications. So in the practical application of high-frequency tube instead of the low-frequency tube, otherwise it can not.
VII． Semiconductor device nomenclature
1． China
By the numbers---Letters---Letters---Digital---（Letter）composition
① The first item is a digital representation of the number of electrodes, such as:2--Diode,3--Transistor
② The second letter indicates the material and the polarity, such as:A -Germanium materialPNPType B--Germanium materialNPNType
C--Silicon materialPNPType D--Silicon materialNPNType E--Compound material
③ The third letter indicates the device type, such as:
G--High-frequency small power tube A -High-frequency high-power tube
X--The low-frequency small power tube D--Low-frequency high-power tube
K--Switch tube W--Regulator P--The ordinary tube E--Rectifier tube N--Damper tube B--Varactor
④ The fourth number that indicates the registration number
⑤ The fifth letter, lettersA, theB, theC, theDAnd represents the prototype of an improved Type
Example:2AP9--Germanium ordinary diode 2CW56--Silicon Zener Diode 3DG6B--SiliconNPNHigh-frequency small power tube3DG6Improved 3AX31--GermaniumPNP- Type low-frequency small power transistor 3BX31--GermaniumNPN- Type low-frequency small power transistor 3CD511--SiliconPNPType low frequency high power transistor 3DD15--SiliconNPNType low frequency high power transistor
2． Japan
By the numbers-letters---Letters--digital--and the letters form
① First digit is expressed as:0--Optoelectronic transistor;1--Diode and rectifier; 2--The transistor and can be controlled rectifier.
② The second letter“S”Expressed as a semiconductor device.
③ The third letter indicates the device type, the first entry is0, the1Without this the third.
A-pnpType high-frequency B-PNP- Type low-frequency C-NPNType high-frequency D-NPN- Type low-frequency
J-PChannel field effect tube K-NChannel field effect tube
④ The first four numbers indicate the registration number.
⑤ The fifth letter in the distinction between the prototype and the variations used with the lettersA, theB, theC, theDAnd represents the prototype of an improved Type.
Example:2SC1815, the2SA1015, the2SC1942, the2SD3298A, the2SD1555, the2SK134Etc. Note: Japanese model transistor in order to mark the convenient and often eliminating the need for models in front of“2S”Such as:A1015, theC1815, theC3298A, theD1555Etc.
3． Europe
By the letter--letters--digital--and letter composition.
① The first item of the alphabet shown in the device of the type.
A -Germanium material B--Silicon material
② The second letter indicates the device type.
A -Detection, switching, mixed-frequency transistor;B--Varactor diode;C--The low-frequency small power tube;F--High-frequency low-power tube;D--The low-frequency small power tube;L--High-frequency high-power tube;S--Small power switching tube;U--High power switching tube:E--Voltage regulator tube;Y--The rectifier tube.
③ The first three numbers indicate the registration number.
A dedicated device with a letter two digits indicate the registration number; universal device three digits of the registration number.
④ The first four letters of the alphabetA, theB, theC, theDAnd represents the prototype of an improved type or by a certain number of sub-file marker.
Example:BF198--For General-purpose devices, SiliconNPNType high frequency low power transistor;BUY71--As a dedicated device, SiliconNPNType high power switching transistor.
4． United States
By the numbers-letters-numbers--and letter composition.
① The first it