Taw qhia txog Kev Kho Cov Txheej Txheem rau Digital Multimeters
Rau cov cuab yeej faulty, thawj kauj ruam yog los xyuas thiab paub qhov txawv ntawm qhov kev ua txhaum yog qhov tshwm sim (tag nrho cov haujlwm tsis tuaj yeem ntsuas) lossis tus kheej (tus kheej lub luag haujlwm lossis tus kheej ntau yam), thiab tom qab ntawd sib txawv qhov xwm txheej thiab daws nws raws li.
Yog tias txhua lub zog tsis tuaj yeem ua haujlwm, lub hwj chim muab hluav taws xob thiab A / D converter circuit yuav tsum tau xyuas kom zoo. Thaum kuaj xyuas cov khoom siv hluav taws xob, tshem tawm cov roj teeb uas tau teem tseg, nias lub hwj huam hloov, txuas qhov kev sojntsuam zoo rau qhov tsis zoo ntawm lub ntsuas hluav taws xob, thiab txuas cov kev sojntsuam tsis zoo rau lub zog zoo (rau digital multimeter). Tig qhov hloov mus rau qhov ntsuas diode. Yog hais tias cov zaub qhia qhov zoo voltage ntawm lub diode, nws qhia tau hais tias lub hwj chim mov yog zoo. Yog tias qhov sib txawv loj, nws qhia tau hais tias muaj teeb meem nrog cov khoom siv hluav taws xob. Yog tias muaj qhov qhib Circuit Court, tsom rau kev kuaj xyuas lub hwj chim hloov thiab cov roj teeb coj. Yog tias muaj kev cuam tshuam luv luv, nws yuav tsum siv txoj hauv kev sib tsoo kom maj mam txiav cov khoom siv hluav taws xob, nrog rau kev tsom mus rau kev tshuaj xyuas lub tshuab ua haujlwm, lub sijhawm, thiab A / D converter. Yog hais tias ib tug luv luv Circuit Court tshwm sim, nws feem ntau puas ntau tshaj ib tug integrated tivthaiv. Tshawb xyuas cov
A / D converter tuaj yeem ua tiav ib txhij nrog lub ntsuas qhov yooj yim, sib npaug rau DC meter taub hau ntawm analog multimeter. Kev tshuaj xyuas tshwj xeeb:
(1) Hloov qhov ntau ntawm cov ntsuas ntsuas mus rau qhov tsawg DC voltage ntau;
(2) Ntsuas seb qhov kev khiav hauj lwm voltage ntawm A / D converter yog qhov qub. Raws li tus qauv ntawm A / D converter siv nyob rau hauv lub rooj, sib xws rau V + tus pin thiab COM tus pin, sib piv cov nqi ntsuas nrog lawv cov txiaj ntsig zoo saib seb lawv phim.
(3) Ntsuas qhov siv voltage ntawm A / D converter. Feem ntau siv digital multimeter siv voltage feem ntau yog 100mV lossis 1V, uas ntsuas DC voltage ntawm VREF + thiab COM. Yog tias nws deviates ntawm 100mV lossis 1V, nws tuaj yeem hloov kho los ntawm lwm lub potentiometer.
(4) Txheeb xyuas tus lej xov tooj nrog xoom input, luv Circuit Court qhov zoo davhlau ya nyob twg IN + thiab tsis zoo davhlau ya nyob twg IN - ntawm lub A/D converter kom lub input voltage Vin=0, thiab lub ntsuas yuav tso saib "00.0" los yog "00.00".
(5) Tshawb xyuas cov teeb ci ntsa iab ntawm lub monitor. Luv luv Circuit Court xeem davhlau ya nyob twg TEST tus pin mus rau qhov zoo zog davhlau ya nyob twg V +, ua rau lub logic hauv av ua siab thiab tag nrho cov digital circuits yuav tsum tsis txhob ua hauj lwm. Vim tias qhov hluav taws xob ncaj qha tam sim no siv rau txhua qhov mob stroke, tag nrho cov hlab ntsha tawg tau teeb thiab cov lus sib dhos qhia "1888" thiab "18888". Yog tias muaj mob stroke uas ploj lawm, xyuas seb puas muaj kev sib cuag tsis zoo lossis xaim tawg ntawm cov khoom sib txuas ntawm tus pin A / D converter thiab cov nplaum nplaum (lossis thaiv), thiab nruab nrab ntawm A / D converter thiab cov zaub.
Yog tias muaj teeb meem nrog ib tus neeg cov ntaub ntawv, nws qhia tau hais tias ob qho tib si A / D converter thiab lub hwj chim mov ua haujlwm zoo. Vim hais tias DC voltage thiab kuj ntau yam sib koom ua ke ntawm voltage divider resistors; AC / DC tam sim no sib koom shunt; AC voltage thiab AC tam sim no sib koom ua ke ntawm AC / DC converters; Lwm yam xws li Cx, HFE, F, thiab lwm yam yog tsim los ntawm cov converters ywj siab. Los ntawm kev nkag siab txog lawv txoj kev sib raug zoo thiab xa mus rau daim duab hluav taws xob, nws yooj yim los nrhiav qhov tsis raug. Yog tias qhov ntsuas ntawm cov cim me me tsis raug lossis cov lej pom tau hloov pauv ntau, nws yog ib qho tseem ceeb uas yuav tau xyuas seb qhov kev sib cuag ntawm qhov hloov pauv yog qhov zoo.
Yog tias qhov ntsuas cov ntaub ntawv tsis ruaj khov thiab cov txiaj ntsig ib txwm suav nrog, thiab lub davhlau ya nyob twg nkag ntawm A / D converter luv luv, thiab cov ntaub ntawv tso tawm tsis yog xoom, feem ntau yog tshwm sim los ntawm kev ua haujlwm tsis zoo ntawm 0.1 μ F reference capacitor.
Raws li cov kev soj ntsuam saum toj no, qhov kev txiav txim yooj yim rau kev kho lub tshuab hluav taws xob digital yuav tsum yog: lub taub hau digital meter → DC voltage → DC tam sim no → AC voltage → AC tam sim no → kuj ntau yam (xws li buzzer thiab xyuas qhov zoo voltage poob ntawm diode) → Cx → HFE, F, H, T, thiab lwm yam. Tab sis nws yuav tsum tsis txhob overly mechanical. Qee qhov teeb meem pom tseeb tuaj yeem daws tau ua ntej. Tab sis thaum ua calibration, nws yuav tsum tau ua raws li cov txheej txheem saum toj no.
Nyob rau hauv luv luv, rau ib tug faulty multimeter, tom qab kev ntsuam xyuas tsim nyog, thawj kauj ruam yog los soj ntsuam qhov ua tau qhov chaw ntawm qhov txhaum, thiab ces nrhiav qhov txhaum qhov chaw raws li daim duab Circuit Court rau hloov thiab kho. Vim yog qhov tseeb ntawm cov multimeters digital, nws yog ib qho tsim nyog yuav tsum siv cov khoom siv nrog tib qhov tsis zoo thaum hloov lawv, tshwj xeeb tshaj yog thaum hloov A / D converters. Nws yog ib qho tseem ceeb uas yuav tsum tau siv cov kev sib xyaw ua ke nruj me ntsis xaiv los ntawm cov chaw tsim khoom, txwv tsis pub muaj kev ua yuam kev thiab qhov yuav tsum tau muaj qhov tseeb yuav tsis ua tiav. Cov hloov tshiab A / D hloov tshiab kuj yuav tsum tau kuaj xyuas raws li txoj kev tau piav qhia ua ntej, thiab yuav tsum tsis txhob poob siab vim nws yog tshiab.
