In routine process, hard to avoid can encounter circuit board, appear various breakdown, but how do you know to maintain? A board is taken on at hand, is the feeling at a loss what to do? Next, small make up take you to learn how to detect on circuit board all sorts of commonly used yuan of parts of an apparatus, church you are fast of begin electron product debug with maintenance.

 

 

 

1, of common diode detect: (include diode of demodulation diode, rectification diode, damp diode, switch diode, follow on current) it is the semiconductor device that becomes by structure of a PN, have one-way and electric character. Detect through using avometer its, retrorse resistance, can the electrode that differentiate gives diode, still but appraise measures a diode to whether damage.

 

 

 

2, of stabilized voltage diode detect: million Europe the watch is carrying the negative pole with stabilized voltage diode to connect, after the anode of the negative end that million Europe expresses and stabilized voltage diode is conterminous, by formulary divide evenly fast jolty million Europe expresses handle, monitor stabilized voltage diode with avometer at the same time two upright voltage are worth (the size that the voltage archives of avometer should inspect stable voltage to be worth and calm) , when the demonstrative voltage that needs avometer indicates stability, this voltage is worth the stable voltage value that is stabilized voltage diode. If measure the stable voltage of stabilized voltage diode to be worth ignore tall ignore low, the sex that shows this diode is not stable.

 

 

 

3, two-way spark of diode detect: , the measurement of retrorse resistance uses avometer R×1k or R×10k file, measure two-way spark diode, retrorse resistance. Normal when its, retrorse resistance all should be infinity. If be measured, retrorse resistance all very small or for 0, show this diode already puncture attaint.

 

 

 

4, of glow diode detect: Measure glow diode with avometer R×1k archives, retrorse resistance, can discover its, retrorse resistance all is close to ∞ (infinity) , because give off light,this is of diode to pressure fall be more than 1.6V (the voltage of the batteries inside archives of R×1k of prep above avometer is worth 1.5V) cause. The R×10k file that uses avometer electroanalysises to a 220μF/25V capacitor charges (black list pen receives capacitor anode, red watch pen receives capacitor negative pole) , receive the capacitor anode after charging negative pole of glow diode anode, capacitor to receive glow diode negative pole again, if glow diode has very bright glitter, explain this glow diode is in good condition.

 

 

Measure general dynatron with avometer of type of pressing with a finger, can regard dynatron as first ” is linked together or “ end waits for two “ in light of the diode that end ” is linked together, be like “ head ” is negative pole for ” of end of positive electrode “ , former for PNP model, latter is NPN model. Can measure diode to be able to judge the stand or fall that 3 machine run, how is diode measured? With two watches the pen receives diode respectively two end, measure so that two block are worth respectively, one comes for a few K a few K, another should be infinity. This is basic it is good.

 

 

 

The positive and negative that 1000 Europe archives measures R*1 to market report writtens guarantee and launch a knot to resistor, general silicon is in charge of hundreds of 1000 Europe, germanium is in charge of thousands of Europe, if be 0 or very small, criterion already puncture, puncture breakdown basically is C pole is mixed between E pole, if be infinity, criterion open circuit, triode possible.

 

 

Method one, avometer detects the simple method of MOS canal stand or fall

 

1. is received with black list pen it is on D pole, red watch pen is received it is on S pole, have the block value of a 500-600 commonly

 

2. falls in premise of the black immobile that express a pen, with red watch the pen nods G pole, next pen of reoccupy red watch measures S pole, can appear guide

 

Pen of 3. red watch receives D pole, after the pen nods G pole, black list receives S pole again, measures block is worth and 1 those who measure is same it is normal to explain MOS provides the job

 

 

 

 

1, what red pen receives MOS on source pole S, the leakage that black pen receives MOS to be in charge of extremely go up, the good directive that express a needle should be infinity. If have block,the value was not measured MOS canal has appearance of leakage of electricity.

 

2, with a 100KΩ – the resistor of 200KΩ is mixed in grid repeatedly on source pole, next what red pen receives MOS on source pole S, the leakage that black pen receives MOS to be in charge of extremely go up, the value that expresses needle directive at this moment is commonly 0, it is to issue charge to pass the grid that this resistor is in charge of to MOS to charge at this moment, produce grid electric field, because electric field generation brings about electric raceway groove to cause,leakage pole is mixed source pole guides, deflexion of reason avometer finger, the point of view of deflexion is old, discharge sex is better.

 

3, mix join grid the resistor of source pole removeds, avometer is red black pen is changeless, if removed,needle of the watch after resistor is retreated stage by stage slowly return tall block or infinity, criterion MOS provides leakage of electricity, changeless in good condition.

 

4, next the grid that a lead is in charge of MOS is mixed source pole join rises, if pressing with a finger returns infinity instantly, criterion MOS is in good condition.

 

How to detect the stand or fall of resistor:

 

Avometer stirs proper resistor file, resistor puts park insulant alone, contact resistor in order to measure a club firm two end, read take resistance, if be inside indicative group cost and error limits, it is normal to be.

 

 

 

Two upright conductor and part of the metal that measure a club do not get the resistance when measuring with any circuit or conductor (include hand or human body) contact, lest disturb,check and give birth to wrong numerical value. If use test clip, resistor also but impending.

 

 

1, put through capacitor and power source, if put through the index of instantaneous avometer does not swing, show capacitor lose effectiveness or open circuit. If express a needle to indicate power source voltage all the time, but do not make however swing, make clear capacitor already short circuit. It is normal that the needle that be like a watch swings, but do not return null, explain capacitor has appearance of leakage of electricity. Because the voltage of place directive is numeric taller, show leakage n is bigger.

 

 

 

2, the compression that measures the auxiliary volts d.c. that look hidebound capacitor uses to cannot exceed the capacitor that be measured, lest damage because of measure and causing capacitor breakdown. Want accurate the size that measures capacitor, need uses capacitance bridge or Q list. Afore-mentioned simple and easy detect method, can judge pressure roughly to express the stand or fall of capacitor only.

 

 

3, the resistor file that holds generous to secure capacitor to be able to use avometer (R×1000) measures capacitor two electrode, see those who express a needle place become enamoured condition, amplitude is bigger, the capacitance that makes clear capacitor is bigger. If check a club to touch down-lead of container getting an electric shock all the time, watch needle should point to around ∞ , otherwise, show this capacitor has appearance of leakage of electricity, its resistance is less, explain leakage n is bigger, criterion capacitor quality is poorer.

 

 

 

4, when the stand or fall that checking capacitor, to compression electroanalysises inferiorly capacitor, resistor archives should be put in R×100 or R×1K archives, the negative end that red watch pen receives capacitor, black list pen is received carrying, at this moment avometer index will swing, restore null next or near null, such specifications electroanalysis the quality of capacitor is qualification. Electroanalysis the size of capacitor is larger, charge time is longer, index swings slower also.

 

How to detect the stand or fall of potentiometer:

 

Very simple, with the resistor archives of avometer, the demarcate that measures the resistance that outboard cites a base twice to should be potentiometer is the biggest resistor. Measure a among to bring foot and outboard random to cite the block cost between the foot only next, and potentiometer of total travel adjustment, observe resistance changes at the same time, its change should show linear, without jump change. And the smallest reach value of the largest block to answer with conform to of its nameplate demarcate!

 

 

 

Potentiometer cites a base: 1, 2, 3. The potentiometer that buys has a total block value, take avometer to receive 1, 3 total block are potentiometer block value, general total block is losing error 5% , 10% the left and right sides. Different potentiometer deviation is different. Receive next 1, 2 or 2, 3 feet rotate subsequently potentiometer axis potentiometer can arise to arrive from initiative resistor the change of the greatest resistance.