Kho cov txheej txheem rau Digital Multimeters
1. Yog tias txhua lub zog tsis tuaj yeem ua haujlwm, lub hom phiaj yuav tsum tau kuaj xyuas lub zog hluav taws xob thiab A / D converter circuit. 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 zoo coj mus rau qhov tsis zoo ntawm lub ntsuas hluav taws xob ntsuas, thiab txuas cov hlau lead tsis zoo rau lub zog zoo (rau digital multimeter). Tig lub hloov mus rau qhov ntsuas txoj hauj lwm ntawm lub transistor thib ob. Yog hais tias cov zaub qhia tau hais tias qhov zoo voltage ntawm lub thib ob transistor, 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 qhov qhib Circuit Court tshwm sim, tsom rau kev kuaj xyuas lub hwj chim hloov thiab cov roj teeb coj. Yog hais tias muaj ib tug luv luv Circuit Court tshwm sim, nws yog tsim nyog los siv lub Circuit Court breaker txoj kev maj mam disconnect lub Cheebtsam uas siv lub hwj chim mov, nrog rau kev tsom mus rau kev soj ntsuam kev ua hauj lwm amplifiers, timers, thiab A / D converters. Yog hais tias ib tug luv luv Circuit Court tshwm sim, nws feem ntau puas ntau tshaj ib tug integrated tivthaiv.
Lub A / D converter tuaj yeem tshawb xyuas ib txhij nrog lub ntsuas qhov yooj yim, uas yog sib npaug rau DC meter taub hau ntawm analog multimeter. Txoj kev tshuaj xyuas tshwj xeeb yog:
1) Tig qhov ntau ntawm cov ntsuas ntsuas mus rau qib qis tshaj ntawm DC voltage;
2) Ntsuas seb qhov ua haujlwm voltage ntawm A / D converter yog qhov qub. Raws li A / D converter qauv siv nyob rau hauv lub rooj, sib xws rau V ntxiv tus pin thiab COM tus pin, ua qhov ntsuas qhov ntsuas raws li lawv cov nqi raug.
3) Ntsuas qhov siv voltage ntawm A / D converter. Tam sim no, cov ntaub ntawv siv hluav taws xob uas feem ntau siv digital multimeter feem ntau yog 100mV lossis 1V, uas yog, ntsuas qhov DC voltage ntawm VREF ntxiv 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 ntxiv rau thiab tsis zoo davhlau ya nyob twg IN - ntawm A / D converter, kom cov input voltage Vin=0, thiab cov twj paj nruag qhia "{{3} }.0" or "00.00".
5) Txheeb xyuas qhov ci ntsa iab tag nrho ntawm lub monitor. Luv luv Circuit Court tus pin xeem ntawm qhov kev xeem kawg rau qhov zoo fais fab mov davhlau ya nyob twg V ntxiv, kom lub logic hauv av yuav muaj peev xwm thiab tag nrho cov digital circuits nres ua haujlwm. Vim tias qhov hluav taws xob DC siv rau txhua qhov mob stroke, lub ntsuas ntsuas ntsuas "1888" thiab cov ntsuas ntsuas ntsuas "18888" thaum txhua qhov strokes tau teeb. Yog tias tsis muaj mob stroke, xyuas qhov sib txuas cov zis tus pin ntawm A / D converter thiab cov nplaum nplaum (lossis thaiv), nrog rau seb puas muaj kev sib cuag tsis zoo lossis cuam tshuam ntawm A / D converter thiab cov zaub.
2. Yog hais tias muaj teeb meem nrog ib tus neeg lub zog, nws qhia tau hais tias ob qho tib si A / D converter thiab fais fab mov ua haujlwm zoo. Vim hais tias DC voltage thiab kuj ntau yam sib koom ua ke ntawm voltage divider resistors; AC thiab DC tam sim no sib koom shunt; AC voltage thiab AC tam sim no sib koom ua ke ntawm AC / DC converters; Lwm yam khoom xws li Cx, HFE, F, thiab lwm yam yog tsim los ntawm kev ywj pheej sib txawv converters. Nkag siab txog kev sib raug zoo ntawm lawv thiab raws li daim duab hluav taws xob, nws yog ib qho yooj yim los nrhiav qhov tsis raug. Yog tias qhov ntsuas me me tsis yog qhov tseeb lossis tus lej pom tau dhia ntau dhau, qhov tseem ceeb yuav tsum tau kuaj xyuas seb qhov kev sib cuag ntawm qhov hloov pauv yog qhov zoo.
3. Yog tias cov ntaub ntawv ntsuas tsis ruaj tsis khov thiab tus nqi ib txwm khaws cia, thiab lub davhlau ya nyob twg input ntawm A / D converter yog luv luv, thiab cov ntaub ntawv tso tawm tsis yog xoom, ces nws feem ntau yog 0.1 μ Ua los ntawm kev ua haujlwm tsis zoo ntawm F's reference capacitor.
Raws li cov kev soj ntsuam saum toj no, cov txheej txheem kho yooj yim rau digital multimeter yuav tsum yog: digital meter taub hau → DC voltage → DC tam sim no → AC voltage → AC tam sim no → tsis kam ntau (xws li buzzer thiab kuaj xyuas qhov zoo voltage poob ntawm lub raj thib ob) → Cx → HFE, F, H, T, thiab lwm yam. Tab sis nws yuav tsum tsis txhob yuav heev mechanical. Qee qhov teeb meem pom tseeb tuaj yeem daws ua ntej. Tab sis thaum ua calibration, nws yuav tsum tau ua raws li cov txheej txheem saum toj no.
