Cia peb kawm saib yuav ua li cas peb xam resistors rau LED

Muab xam los ntawm resistors rau LEDs - Qhov no yog ib qho tseem ceeb heev lag luam uas yuav tsum tau nqa tawm ua ntej uas koj txuas lub LED mus rau ib tug hwj chim qhov twg los. Qhov no yuav txiav txim seb qhov kev kawm ntawm ob lub diode thiab tag nrho cov Circuit Court. Lub resistor yuav tsum tau muaj nyob rau hauv lub Circuit Court nyob rau hauv series nrog ib tug LED. Qhov no lub caij no yog tsim los txo tam sim no ntws los ntawm lub diode. Yog hais tias lub resistor muaj ib tug me me kuj tsawg dua yuav tsum tau, ces tus LED yuav tsis (hlawv) thiab yog hais tias tus nqi ntawm no parameter yuav tsum muaj ntau tshaj li tsim nyog, lub teeb ntawm lub semiconductor caij no yuav tsum yog ib yam nkaus thiab dim.

Muab xam los resistors rau lub LEDs yuav tsum tau ua los ntawm cov nram qab no mis R = (US - UL) / kuv, qhov twg:

• US - mov voltage;
• UL - voltage diode hwj chim (feem ntau 2 volts thiab 4);
• I - tam sim no ntawm lub diode.

Nco ntsoov xyuas kom meej tias cov xaiv tus nqi ntawm cov hluav taws xob tam sim no yog me dua cov nyiaj pab ntau tshaj tam sim no tus nqi ntawm lub semiconductor caij. Ua ntej cov tswv yim rau lub xam, koj yuav tsum muab cov nqi no nyob rau hauv amps. Feem ntau nws yog hauv lub passport cov ntaub ntawv teev nyob rau hauv milliamps. Yog li, raws li ib tug tshwm sim ntawm cov lus teb yog tau txais tus nqi ntawm lub nominal kuj ntawm lub resistor nyob rau hauv ohms. Yog hais tias lub resulting nqi yuav tsis tib yam nrog ib tug standard resistor, koj yuav tsum xaiv lub ze tshaj loj denomination. Los yog nws yog tau mus cuag nyob rau hauv series ob peb me me thiab me me kuj hais li ntawd tag nrho cov sib npaug rau hauv lub hom phiaj kuj.

Piv txwv li, qhov no yog yuav ua li cas peb xam resistors rau LEDs. Cia peb xav hais tias peb muaj ib lub hwj chim mov nrog ib tug tso zis voltage ntawm 12 volts, thiab ib tug LED (UL = 4 V). Qhov yuav tsum tau tam sim no yog 20 ma. Peb txhais nws rau tau 0,02 amps thiab A. Peb yuav tam sim no npaj mus rau lub xam ntawm R = (12 - 4) / 0,02 = 400 ohms.

Tam sim no xav li cas lub xam yuav tsum tau nqa tawm ntawm ib tug series kev twb kev txuas ntawm ib tug plurality ntawm semiconductor ntsiab. Qhov no yog tshwj xeeb tshaj yog muaj tseeb thaum ua hauj lwm nrog LED ib daim hlab. Lub series kev twb kev txuas thiaj lub hwj chim noj thiab enables rau ib txhij cuag ib tug loj tus naj npawb ntawm cov ntsiab. Nco ntsoov, txawm li cas los, hais tias tag nrho cov series-kev cob cog rua LEDs yuav tsum yuav ntawm tib hom, thiab lub hwj chim mov - sufficiently haib. Qhov ntawd yog txoj kev yuav tsum xam resistors rau LEDs nyob rau hauv series kev twb kev txuas. Xav hais tias hais tias peb muaj ib cov saw ntawm 3 ntsiab (txhua voltage yog 4 volts) thiab ib tug 15-volt fais fab mov. Peb txiav txim seb lub voltage UL. Yuav kom qhov no yuav tsum tau ntxiv rau txhua lub diodes nuj nqis 4 + 4 + 4 = 12 volts. Passport LED tam sim no tus nqi ntawm 0,02 A, peb xam R = (15-12) / 0,02 = 150 ohms.

Nws yog ib qho tseem ceeb yuav tau nco ntsoov hais tias thaum uas tig mus ntawm twb kev txuas LEDs, muab tso rau nws mob me, ib tug lub tswv yim phem. Qhov no yog hais tias cov ntsiab muaj ib tug variation ntawm tsis, txhua tus uas yuav tsum tau txawv voltages. Qhov no ua rau lub fact tias lub xam ntawm LEDs - yog ib tug futile ce. Nrog rau qhov no kev twb kev txuas, txhua lub caij yuav ci nrog nws brightness. Qhov teeb meem no yuav raug cawm dim los ntawm ib limiting resistor rau txhua diode nyias.

Nyob rau hauv xaus, peb ntxiv hais tias raws li txoj ntsiab cai no yog xam tag nrho cov LED los ua ke nrog rau lub teeb nrog LEDs. Yog hais tias koj xav rau nws tus kheej-sib sau ua ke xws li ib tug qauv, cov ntaub ntawv teb rau koj yuav yuav yam.