Ob txoj hauv kev ntsuas qhov tsis kam nrog Digital Multimeter
Kev ntsuas plaub-xaim ntxiv rau qhov ntsuas qhov tam sim no
Txoj kev ntsuas plaub-xaim tau hais los saum toj no tuaj yeem pab cov engineers kom ua tiav qhov kev ntsuas siab ntawm multimeter tiv thaiv kev ua haujlwm, tab sis nyob rau hauv txoj kev ntsuas plaub-xaim, qhov tseeb ntawm qhov tam sim no qhov tam sim no tseem ceeb heev. Nws raug nquahu kom siv qhov chaw sab nraud thiab ruaj khov dua qhov chaw tam sim no.
Nws yuav tsum tau muab sau tseg hais tias qhov loj ntawm lub sab nraud qhov tam sim no qhov tam sim no yuav tsum sib npaug zos rau qhov loj ntawm qhov tam sim no qhov tam sim no ntawm cov multimeter. Sab nraud qhov tam sim no qhov chaw tam sim no peb siv yog tsim los ntawm high-precision siv voltage qhov chaw MAX6250, ib qho kev ua hauj lwm amplifier thiab ib tug tam sim no-expanding composite raj, raws li qhia nyob rau hauv daim duab 2. Qhov kub drift ntawm qhov voltage MAX6250 yog tsawg dua los yog sib npaug. mus rau 2ppm/degree, thiab lub sij hawm drift ΔVout/t=20ppm/1000h. Hauv cov txheej txheem ntsuas no, qhov tam sim no kuv yuav tsum yog 800μA ~ 1mA, thiab R yog qhov kub tsis tshua muaj zog drift wirewound resistor (yog tias kuv=1}mA, R=5kΩ), ces qhov kub thiab txias thiab lub sij hawm drift ntawm kuv yog sib npaug rau qib MAX6250.
Feeder Resistance Compensation Measurement Method
Txoj kev pub nyiaj tiv thaiv kev tiv thaiv yog lwm txoj kev ntsuas siab tshaj plaws rau kev ntsuas kev tiv thaiv nrog multimeter. Hauv kev lag luam kev lag luam, yog tias yuav tsum muaj kev ntsuas kev ua haujlwm siab, qhov kev sib txuas ntawm peb-xaim feem ntau yog xaiv kom qhov ntsuas tsis kam txuas nrog cov kab hauv av. txuas. Lub hauv paus ntsiab lus ntawm txoj kev sim no yog qhia hauv daim duab 3. Thaum siv cov txheej txheem no rau kev ntsuas, tam sim no kuv yog 800μA ~ 1mA, thiab R yog qhov kub thiab txias heev drift wirewound resistor (yog tias kuv=1}mA, R{ {8}}kΩ), tom qab ntawd qhov kub thiab txias ntawm lub sijhawm tam sim no kuv sib npaug rau qib MAX6250.
