Commonly used electron yuan parts of an apparatus detects method and experience

A lot of youths like electronic technology, feeling from capable already maintenance in the home small electric equipment and peculiar existence feeling, and the base that the electron maintains is an electron yuan of parts of an apparatus detect, yuan of parts of an apparatus a basic skill that detecting is electronic maintenance, how to detect effectively the relevant parameter of yuan of parts of an apparatus, those who judge yuan of parts of an apparatus is normal, not be a machine-made thing, must use different method according to yuan of different parts of an apparatus, what judge yuan of parts of an apparatus thereby is normal. Particularly right for abecedarian, adroitness control is commonly used of yuan of parts of an apparatus detect method and experience very be necessary, be opposite below commonly used electron yuan of parts of an apparatus detect experience and method undertake introductory offerring is opposite taking an examination of.

One, of resistor detect method and experience:
Of 1 fixed resistor detect.
A general two watches pen (do not divide losing) bring a foot to connect with the two end of resistor respectively can measure an effective resistance. Measure precision to rise, should the basis is measured resistor is nominal the bulk of the value will choose span. What block scale as a result of ohm is nonlinear relation, a paragraph of its intermediate graduation is relatively careful, because this should make index indicated value falls to the middle position of scale as far as possible, namely the 80% radian of 20% ～ with complete initiative scale inside limits, measure in order to make more accurate. Differ according to resistor error grade. Reading and nominal ± of be patient of parts between block value 5% , ± 10% or ± the error of 20% . Be like not conform to, exceed error range, explain this resistance changes was worth.
B attention: When the test, when the resistance that measuring value of block of above of Ω of a few K especially, the resistor that the hand does not touch the electric part; that expresses pen and resistance is detected comes down from the solder in circuit, want solder to open one build at least, lest the other component in circuit produces an effect to the test, cause the block that measures resistance of error; lubricious annulus to although can decide with lubricious annulus mark,be worth, but still had better use avometer to check its when use actual block value.
Of resistor of 2 cement detect. Detect the method of cement resistor and note and detect common and fixed resistor is identical.
Of resistor of 3 fusing detect. In circuit, after open a way of fusing resistor fusing, can make judgement according to experience: If discover fusing resistor surface nigrescent or scorch, can concluding is his bear is overweight, the electricity that carries it exceeds rating; of a lot of times be caused by if its surface does not have any traces and open circuit, make clear flow to the electricity that pass just is equal to or be more than its a bit rated fusing value. Do not have the judgement with the fusing good resistor of any traces to the surface, but × of R of avometer of have the aid of 1 block will measure, measure to assure accurate, answer to break frit resistor one aspect of the matter to fall from the solder on circuit. If measure gotten block value to be infinity, show this fusing resistor already invalidation open a way, the block value that if measure,gets and nominal the value differs very far, show resistor changes value, unfavorable also reuse. Maintaining the discovery in practice, also resistor of a few fusing is in in circuit by the phenomenon of puncture short circuit, when detecting, also should give attention.
Of 4 potentiometer detect. When checking potentiometer, want roll power coming back above all, see power coming back roll is flowing, switch is quick, switch is connected, when breaking ” Da of noise made in coughing or vomiting ” sound is ringing, listen to potentiometer interior to contact dot and the sound that resistor body chafes, if have ” rustle ” sound, explain quality is bad. When checking with avometer, first the size that according to be being measured potentiometer block is worth, the appropriate resistor that chooses good avometer is blocked, can undertake detecting by undermentioned method next.
A is blocked with the ohm of avometer measure ” 1 ” , ” 2 ” two end, what its reading should be potentiometer is nominal block value, the finger that is like avometer is not moved or block value differs a lot of, show this potentiometer already damaged.
B detects the vivid luffing jib of potentiometer and resistor piece the contact is good. The ohmic file that uses avometer is measured ” 1 ” , ” 2 ” (or ” 2 ” , ” 3 ” ) two end, come back the runner shaft of potentiometer by anticlockwise direction to adjacent ” close ” the position, at this moment resistance Yue Xiaoyue is good. Again suitable hour hand rotates slowly axial handle, resistance should increase gradually, the finger in expressing a head should move smoothly. Come back when axial handle to extreme position ” 3 ” when, block is worth should of close potentiometer nominal value. If the finger of avometer is in,the axial handle of potentiometer has jumpy appearance in rotational process, explain mobile contact has the trouble with undesirable contact.
5 temperature coefficient thermal resistor (of PTC) detect. When detecting, with avometer R × 1 block, specific can separate pace operation: A normal temperature detects (indoor temperature is close to 25 ℃ ) ; contacts two watches pen PTC thermal resistor two bring a foot to measure give its actual block value, and with nominal block cost is comparative, both differs in ± it is normal to be namely inside 2 Ω . Actual block value if with nominal block value has differred big, explain its performance is bad or already damaged. B is added detect; checks normal foundation to go up in normal temperature, can undertake the 2nd pacing tries, add lukewarm detect, one heat source (for example electric iron) stand by PTC thermal resistor to heat to its, monitor its to lift and increase what whether resistance follows temperature with avometer at the same time, so, explain thermal resistor is normal, the value that be like block is invariant, explain its function changes bad, cannot continue to use. The attention does not make heat source and PTC thermal resistor rely on too close or directly to contact thermal resistor, iron its in order to prevent bad.
6 loses temperature coefficient thermal resistor (of NTC) detect.
(1) , measure nominal resistance Rt
The method that measures NTC thermal resistor with avometer and the method that measure common and fixed resistance are same, namely according to NTC thermal resistor nominal the resistor with block value right choice blocks the real value that can measure a Rt directly. But because NTC thermal resistor is right temperature is very sensitive, the following should notice when reason checks: When producing manufacturer to be 25 ℃ in environmental temperature, Rt of A 　 is measured, when measuring Rt with avometer so, also answer to undertake when environmental temperature is close to 25 ℃ , in order to assure the reliability of the test. B measures power to must not provide a value more than, lest voltaic fuel factor is caused,measure an error. C notices to be operated correctly. When the test, do not hold thermal resistor put oneself in another’s position with the hand, produce an effect in order to prevent human body temperature to the test.
(2) , appraise measures room temperature of preexistence of T of temperature coefficient α measure below T1 resistance Rt1, reoccupy electric iron makes heat source, stand by thermal resistor Rt, measure a resistance RT2, measure with the thermometer at the same time piece right now the average temperature T2 of surface of thermal resistor RT has consideration again.
7 is pressed quick of resistor detect. The R × 1k that uses avometer is blocked measure pressure quick resistor two cite a base between, retrorse insulation resistance, all be infinity, otherwise, explain leakage current is big. If what measure resistance very small, the specification is pressed quick resistor already damaged, cannot use.
Of resistor of 8 photosensitive detect. A uses one black scrip photosensitive resistor pervious to light the window obscures, right now the finger of avometer maintains basically do not move, block value approachs infinity. This value explains photosensitive resistor performance has been jumped over greatly more. If very small or this value is adjacent,be 0, demonstrative photosensitive resistor already was burned wear attaint, cannot continue to use again.
What B aims one illuminant photosensitive resistor is pervious to light the window, the finger of avometer is right now due relatively substantially swing, block value is reduced apparently. This value jumps over function of resistor of small specification photosensitive to had been jumped over. If this value is very great even infinity, show open a way of photosensitive resistor interior damages, also cannot continue to use again.
Resistor of photosensitive of C general is pervious to light the window aims incident light, be in with small black scrip the rock of shading window upside of photosensitive resistor, make meantime is broken get light, right now avometer finger should be controlled along with the rock of black scrip swing. If avometer finger stops in some position not to follow a scrip from beginning to end rock and swing, explain the photosensitive material of photosensitive resistor has damaged.
2, of capacitor detect method and experience
Of 1 fixed capacitor detect
A detects the small electric capacity under 10pF because the fixed capacitor size under 10pF is too small, undertake metrical with avometer, can qualitative examination whether do its have leakage of electricity, in-house short circuit or puncture phenomenon. When measuring, can choose 10k of avometer R × to block, two when receive capacitance arbitrarily respectively with two watches pen cite a base, block value should be infinity. If measure value giving block (index swings right) for 0, show attaint of capacitance leakage of electricity or in-house puncture. B detects whether does fixed capacitor of 01 μ F have 　 of 10PF ～ 0 charge phenomenon, judge its stand or fall then. Avometer chooses R × 1k to block. The β value of two dynatron all is 100 above, and penetrable electric current wants small. Can choose the model silicon dynatron such as 3DG6 to comprise multiple tube. Of avometer red with black list the pen parts with multiple tube blast off extremely E and collector C are conterminous. As a result of the enlarge action of compound dynatron, the capacitance that be measured fill discharge process to give enlarge, make avometer finger places extent to increase, facilitate thereby observation. What should notice is: When the test is operated, when the capacitance that measuring lesser size especially, should exchange repeatedly the capacitance that be measured brings a foot to contact A, B at 2 o’clock, just can see avometer hand apparently swing. C to 0 　 the fixed capacitance of above of 01 μ F, the R × 10k of usable avometer blocks direct test capacitor to have without charge process and have without in-house short circuit or leakage of electricity, the scope magnitude that can swing right according to pressing with a finger estimates the size that gives capacitor.
2 electroanalysises of capacitor detect
Because A electroanalysises more general and fixed capacitance gets the capacity of capacitance greatly much, so, when measuring, answer to choose appropriate span in the light of distinct size. According to experience, usually, 47 μ of 1 ～ the capacitance between F, 1k of usable R × is blocked measure, the capacitance that is more than 47 μ F can use R × 100 block measure.
B receives pen of avometer red watch negative pole, black list pen receives positive electrode, in the instant of firm contact, avometer finger namely right deflexion is bigger degree of bias (block to same resistor, the size is larger, amplitude jumps over big) , then gradually circumgyrate of towards the left, until stop in some position. Right now block value is to electroanalysis of capacitance to block of leakage of electricity, this value is more than block of retrorse leakage of electricity slightly. Use experience actually to make clear, electroanalysis the leakage resistor of capacitance should be in commonly above of Ω of hundreds of K, otherwise, will cannot work normally. In the test, if to, all do not have charging phenomenon reversely, express a needle to be not moved namely, explain the capacity disappears or if what; of in-house open circuit measures block to be worth very small or for 0, explain capacitance leakage of electricity is big or already puncture attaint, cannot reuse. C to, negative pole mark electroanalysises unidentifiedly capacitor, can use afore-mentioned methods that measure block of leakage of electricity to try differentiate. Measure block of leakage of electricity arbitrarily first namely, remember its size, exchange watch pen to measure a value of a block again next. Value of the block in be being measured twice is great it is that time to receive a standard, namely what black list pen receives is positive electrode, what red watch pen receives is negative pole. D uses avometer resistor to block, use electroanalysis capacitance undertakes, the method that charges reversely, swing right according to pressing with a finger the size of extent, but appraise is measured piece electroanalysis the capacity of capacitance.
Of 3 alterable capacitor detect
A comes back gently with handle gently move runner shaft, should feel very flowing, when the feeling loosens sometimes, should not tighten have appearance blocking sluggish even. Will carry an axis forward, hind, on, below, left, right when waiting for each direction to drive, runner shaft is not due the phenomenon that become loose. B comes back with a hand move runner shaft, another handle gently touchs rotor series outside predestined relationship, should not feel any pines take off a phenomenon. Undesirable alterable capacitor is contacted between runner shaft and rotor, cannot continue to use again. C blocks 10k of × of avometer park R, the rotor that a hand expresses two the pen to receive alterable capacitor respectively and calm piece terminals, runner shaft of another hand general slowly come back move a few to make a round trip, avometer finger should be not moved in infinity position. Coming back in the process that uses runner shaft, if pressing with a finger is pointed to sometimes 0, demonstrative rotor and calm piece between if; of dot of existence short circuit comes up against some angle, avometer reading does not appear however for infinity certain block value, the specification is alterable capacitor rotor and calm piece between phenomenon of existence leakage of electricity.
3, inductor, transformer detects method and experience
1 color piles up inductor detect
× of avometer park R 1 block, pen of red, black list receives color to pile up the either terminals of inductor each, right now index should swing right. The basis measures the resistance volume that go out, but particular branch is undermentioned 3 kinds of circumstances undertake differentiating:
A is measured resistance of lubricious code inductor is 0, its interior has trouble of short circuit sex. B is measured kind of size that piles up inductor dc resistance and wind the enamel-insulated wire way that makes inductor coil place use, circle the number that make a group to have immediate concern, want to be able to measure a resistance only, can thinking the color that be measured piles up inductor is normal.
Of transformer of the week in 2 detect
A dials avometer to R × 1 block, according to in each winding of week transformer brings a foot to arrange the rule, one by one checks each winding open a case, it is normal to judge its then. B detects insulation property blocks 10k of × of avometer park R, do tests of following a few kinds of state:
(The resistance; between 1) primary winding and sub winding
(The resistance; between 2) primary winding and crust
(The resistance between 3) sub winding and crust.
Afore-mentioned test result cent appear 3 kinds of circumstances:
(1) block value is infinity: Normal;
(2) block value is 0: Have; of breakdown of short circuit sex
(3) block value is less than infinity, but be more than 0: Have trouble of sex of leakage of electricity.
Of transformer of 3 power source detect
Whether does A have apparently unusual appearance through observing the appearance of transformer will check its. If whether coil down-lead ruptures, sealing off, whether does insulating material have scorch trace, whether does screw of core close solid have become loose, silicon steel piece have without rustily, whether does winding coil have appear etc.
B insulating properties checks. Block with 10k of avometer R × measure respectively core and primary, primary layer of as sub as each sub, core and each, electrostatic screen and vent in the sides of a garment are sub, sub the resistance between each winding, avometer finger all should show in infinity the position is not moved. Otherwise, explain transformer insulation property is undesirable.
C coil connects detect. × of avometer park R 1 block, in the test, if the resistance of a certain winding is infinity, explain this winding has trouble of open circuit sex.
At the beginning of D differentiate, secondary coil. Power source transformer is primary bring foot and sub citing a base is to part commonly from two side derivative, and primary winding much mark has 220V model of written characters, sub winding criterion rated voltage is worth line out, wait like 15V, 24V, 35V. Undertake discriminating according to these mark again.
E sky carries electricity detect.
(A) measures a way directly. Will sub all winding is all open circuit, block avometer park alternating current (500mA, string together primary winding. When the outlet of primary winding inserts report of 220V communication town, what avometer place indicates is to carry electric current to be worth for nothing. The 10% ～ that this value should not be more than transformer to be fully loaded with electric current 20% . The normal sky of transformer of power source of facility of general and common electron carries electric current to should be controlled in 100mA. If exceed too much, explain transformer has trouble of short circuit sex. (B) indirect method of measurement. Establish ties in the primary winding of transformer 　 of a 10 / the resistor of 5W, sub still carry for nothing entirely. Dial avometer to alternating voltage to block. After appending report, with two watches the pen measures the voltage drop U that gives two end of resistor R, hold voltaic I air with sky of Ohm’s law cipher out next, namely I empty =U/R.
F sky carries voltage detect. power source transformer primary receive 220V town report, receive with avometer alternating voltage ordinal the sky that measures each winding carries voltage to be worth (U21, U22, U23, U24) should accord with a requirement to be worth, allow error limits to be commonly: ± of high-pressured winding ≤ 10% , ± of low-pressure winding ≤ 5% , the voltage of two groups of symmetrical winding that take central take a percentage of a deal is poor should ≤ ± 2% .
Transformer of power source of G general small-power allows temperature rise to be 40 ℃ ～ 50 ℃ , if place is better with insulating material quality, allow temperature rise to still can rise.
H detects differentiate the homonymic end of each winding. When transformer of use power source, the sub voltage that needs to get place sometimes, but will two or series connection of many sub winding rises use. When using series connection law to use power source transformer, the homonymic end of each winding that attends series connection must join correctly, cannot make a mistake. Otherwise, transformer cannot work normally. I. Of breakdown of sex of short circuit of power source transformer detect integratedly differentiate. Power source transformer short-circuits the main symptom after sexual breakdown is calorific and serious output voltage with sub winding wrong. Normally, coil interior circles the dot jumps over a short circuit much, short-circuit current is bigger, and transformer is calorific more serious. Detect the simple method that judges power source transformer to whether have trouble of short circuit sex is to measure carry electricity for nothing () has introduced before test method. Put in the transformer of short circuit breakdown, its carry electricity for nothing the value will be ambitious 10% at be fully loaded with electric current. When short circuit is serious, transformer is in carry for nothing add electric hind a few seconds in can give out heat quickly, core of the feeling that use a hand can have the feeling of very hot hand. Need not measure right now carry electric current to be able to conclude transformer has short circuit to nod existence for nothing.