Intro & Tutorial ntawm Programmable Power Supply!: 7 Cov Kauj Ruam

2024 Tus sau: John Day | [email protected]. Kawg hloov kho: 2024-01-30 09:29

Yog tias koj tau xav tsis thoob txog cov khoom siv hluav taws xob programmable, tom qab ntawd koj yuav tsum hla cov lus qhia no kom tau txais kev paub tiav & piv txwv piv txwv ntawm lub zog siv tau.

Tsis tas li txhua tus neeg uas xav paub txog hluav taws xob, thov mus hla cov lus qhia no los tshawb txog qee yam tshiab uas ntxim nyiam….

Nyob twj ywm !!

Kauj Ruam 1: Lub Hwj Huam Lub Hwj Huam Muaj Dab Tsi thiab Dab Tsi Ua Rau Nws Sib Txawv?

Nws tau ib pliag txij li kuv tau tshaj tawm cov lus qhia tshiab. Yog li kuv xav kom nrawm xa cov lus qhia tshiab ntawm cov cuab yeej tsim nyog (rau txhua tus nyiam ua haujlwm/nyiam siv hluav taws xob/tshaj lij) uas yog lub zog siv tau.

Yog li, thawj lo lus nug tshwm sim ntawm no tias qhov khoom siv tau yog dab tsi?

Lub zog hluav taws xob tuaj yeem siv tau yog hom kev tawm hluav taws xob uas tso cai rau kev tswj hwm tag nrho ntawm qhov tso tawm qhov hluav taws xob & tam sim no ntawm chav tsev los ntawm digital interface/analog/RS232.

Yog li dab tsi ua rau nws txawv ntawm ib txwm LM317/LM350/lwm yam IC raws cov kab hluav taws xob tso tawm? Cia peb saib qhov tseem ceeb sib txawv.

1) Qhov sib txawv loj loj yog kev tswj hwm:

Feem ntau peb ib txwm LM317/LM350/lwm yam IC raws kev xa khoom ua haujlwm ntawm CV (qhov hluav taws xob tsis tu ncua) hom uas peb tsis muaj kev tswj hwm tam sim no. Qhov rub tawm tam sim no raws li nws xav tau qhov peb tsis tuaj yeem tswj nws. cov khoom siv tau, peb tuaj yeem tswj hwm ob qho Voltage thiab cov haujlwm tam sim no ib tus zuj zus.

2) Tswj kev sib tham:

Hauv peb qhov LM317/LM350 raws cov khoom siv, peb tig lub lauj kaub thiab qhov hluav taws xob tso tawm sib txawv raws li.

Hauv kev sib piv, hauv cov phiaj xwm siv hluav taws xob, peb tuaj yeem teeb tsa qhov ntsuas tsis siv tus lej lej lossis peb tuaj yeem hloov nws siv tus lej nkag teb chaws lossis txawm tias peb tuaj yeem tswj qhov ntsuas ntawm lub PC nyob deb.

3) Kev tiv thaiv tso tawm:

Yog tias peb luv qhov tso tawm ntawm peb cov khoom ib txwm muaj, nws yuav txo qhov hluav taws xob thiab muab tag nrho tam sim no.

Tab sis hauv kev sib piv, Hauv qhov khoom siv tau, peb tuaj yeem kaw qhov tso tawm tag nrho (yog tias peb xav tau) thaum muaj luv luv tshwm sim.

4) Tus neeg siv interface:

Feem ntau hauv cov khoom siv ib txwm muaj, peb yuav tsum tau xa ib lub multimeter los tshuaj xyuas qhov hluav taws xob tso tawm txhua lub sijhawm.

(NB: Thov txheeb xyuas kuv 3A qhov sib txawv ntawm lub rooj zaum lub zog muab qhia rau ntawm no uas suav nrog inbuilt Voltage & Tam sim no nyeem tawm ntawm cov xim xim)

Sib nrug los ntawm qhov ntawd, hauv qhov khoom siv tau, nws muaj cov khoom tsim tawm uas qhia tag nrho cov ntaub ntawv tsim nyog xws li qhov hluav taws xob tam sim no/tam sim no amp/teeb hluav taws xob/teeb amp/hom kev ua haujlwm thiab ntau yam ntxiv.

5) Tsis muaj cov txiaj ntsig:

Piv txwv tias koj xav khiav OP-AMP raws li Circuit/audio Circuit uas koj yuav xav tau txhua Vcc, 0v & GND. Peb cov khoom siv tawm yuav muab tsuas yog Vcc & GND (ib qho channel tso tawm) yog li koj tsis tuaj yeem ua haujlwm ntawm cov Circuit no siv cov khoom xa tawm (Koj yuav xav tau ob ntawm lawv txuas nrog hauv kab ntawv).

Hauv kev sib piv, qhov khoom siv tau yooj yim muaj qhov tsawg kawg ob qhov kev tso tawm (qee qhov muaj peb) uas yog hluav taws xob sib cais (tsis yog qhov tseeb rau txhua qhov khoom siv tau) thiab koj tuaj yeem koom nrog lawv tau yooj yim kom tau txais koj li Vcc, 0, GND.

Kuj tseem muaj ntau qhov sib txawv, tab sis cov no yog qhov sib txawv tseem ceeb uas kuv tau piav qhia.

Tsis tas li, Hauv kev sib piv nrog SMPS, lub zog siv hluav taws xob tuaj yeem muaj lub suab nrov me me (tsis xav tau AC cov khoom siv/hluav taws xob me me/EMF thiab lwm yam) ntawm qhov tso tawm (Raws li nws yog linear).

Tam sim no cia peb txav mus rau qib tom ntej!

NB: Koj tuaj yeem tshawb xyuas kuv cov vis dis aus hais txog kuv li Rigol DP832 programmable power supply here.

Kauj Ruam 2: CV & CC Hom Ntawm Ib Lub Hwj Huam Li Cas?

Nws yog qhov tsis meej pem ntau rau peb txhua tus thaum nws los txog qhov teeb meem ntawm CV & CC. Kuv paub daim ntawv puv tab sis ntau zaus, peb tsis muaj lub tswv yim zoo li cas lawv ua haujlwm li cas. Peb saib ntawm ob hom thiab ua qhov sib piv ntawm qhov lawv txawv ntawm lawv qhov kev xav ua haujlwm li cas.

CV (qhov hluav taws xob tas li) hom:

Hauv CV hom (txawm hais tias muaj ib qho khoom siv hluav taws xob/Roj teeb them nyiaj/yuav luag txhua yam uas muaj nws), cov cuab yeej feem ntau tswj hwm qhov hluav taws xob tas li ntawm qhov tso tawm ywj pheej ntawm qhov tam sim no kos los ntawm nws.

Tam sim no cia ua piv txwv.

Rau qhov hais tias, Kuv muaj 50w dawb LED uas ua haujlwm ntawm 32v & siv 1.75A. Tam sim no yog tias peb txuas lub LED rau lub zog hluav taws xob nyob rau hauv qhov hluav taws xob tsis tu ncua & teeb tsa lub zog rau 32v, lub zog siv hluav taws xob yuav tswj cov zis hluav taws xob thiab yuav tswj hwm nws ntawm 32v lawm. Nws yuav tsis saib xyuas tam sim no siv los ntawm LED.

Tab sis

Cov hom LEDs kos tam sim no ntau dua thaum lawv kub dua (piv txwv li nws yuav kos ntau dua tam sim no tshwj xeeb ntawm cov ntawv teev tseg piv txwv li 1.75A & tuaj yeem nce siab li 3.5A. Yog tias peb tso lub hwj chim ntawm CV hom rau LED no, nws yuav tsis saib qhov kos tam sim no & tsuas yog tswj cov hluav taws xob tso tawm thiab yog li, LED yuav raug puas ntsoog thaum kawg ntawm qhov ntev vim yog siv ntau dhau tam sim no.

Nov yog hom CC los ua si !!

CC (qhov tam sim no/tswj tam sim no) hom:

Hauv CC hom, peb tuaj yeem teeb tsa MAX tam sim no rub los ntawm kev thauj khoom & peb tuaj yeem tswj hwm nws.

Rau qhov hais tias, peb teeb tsa qhov hluav taws xob ntawm 32v & teeb tsa qhov siab tshaj tam sim no rau 1.75A thiab txuas tib lub LED rau cov khoom siv., peb lub zog siv hluav taws xob yuav tswj hwm tib lub amp piv txwv li 1.75 ntawm qhov tso tawm los ntawm LOWERING THE VOLTAGE (yooj yim Ohm txoj cai) thiab yog li, peb cov LED yuav raug cawm nyob ntev.

Tib yam mus rau lub roj teeb them thaum koj them ib qho SLA/Li-ion/LI-po roj teeb.

Wb coj lwm qhov piv txwv uas peb xav kom them lub roj teeb 4.2v/1000mah uas tau ntsuas ntawm 1C (piv txwv li peb tuaj yeem them lub roj teeb nrog qhov siab tshaj tam sim no ntawm 1A). C yog 500mA.

Tam sim no peb yuav teeb lub hwj chim rau 4.2v thiab teeb lub zog tam sim no rau 500mA thiab yuav txuas lub roj teeb rau nws. Ntawm no lub roj teeb yuav sim nqa ntau tam sim no tawm ntawm cov khoom siv rau thawj zaug tab sis peb lub zog siv hluav taws xob yuav tswj hwm tam sim no los ntawm Txo qhov hluav taws xob me ntsis. Yog li lub roj teeb hluav taws xob yuav nce ntxiv thaum kawg, qhov muaj peev xwm sib txawv yuav tsawg dua ntawm Cov Khoom thiab lub roj teeb thiab qhov tam sim no kos los ntawm lub roj teeb yuav raug txo qis. poob qis dua 500mA, cov khoom siv yuav hloov mus rau hom CV & tswj kom ruaj khov 4.2v ntawm qhov tso tawm kom them lub roj teeb rau lub sijhawm tas!

Nthuav, tsis yog nws?

Kauj Ruam 3: Muaj Ntau Yam Tawm Hauv No !!

Ntau qhov khoom siv hluav taws xob tuaj yeem siv tau los ntawm cov neeg muab khoom sib txawv. Yog li yog tias koj tseem nyeem tam sim no thiab txiav txim siab kom tau txais ib qho, thawj zaug koj yuav tsum txiav txim siab qee qhov !!

Txhua & txhua qhov khoom siv hluav taws xob sib txawv los ntawm ib leeg hauv qhov tseeb, tsis muaj cov tso tawm raws, tag nrho cov zog tso tawm, Max voltage-tam sim no/tso tawm thiab lwm yam thiab lwm yam.

Tam sim no yog tias koj xav kom muaj ib tus, tom qab ntawd ua ntej koj txiav txim siab qhov siab tshaj plaws qhov hluav taws xob & tam sim no koj feem ntau ua haujlwm nrog rau koj li niaj hnub siv! Tom qab ntawd los tag nrho lub zog tso tawm xws li ntau npaum li cas lub zog koj xav tau (P = VxI tus qauv). Tom qab ntawd mus rau lub interface zoo li ib yam koj xav tau tus lej tus lej lej/teb encoder style lossis koj xav tau analog hom interface thiab lwm yam.

Tam sim no yog tias koj tau txiav txim siab, thaum kawg los txog qhov tseem ceeb tseem ceeb piv txwv li tus nqi. Xaiv ib qho raws li koj cov peev nyiaj (thiab pom tseeb tias yog tias cov txheej txheem kev hais saum toj no muaj nyob hauv nws).

Thiab kawg tab sis tsis tsawg kawg, pom tseeb ntawm tus neeg muag khoom Kuv xav kom koj yuav los ntawm tus neeg xa khoom muaj npe thiab tsis txhob hnov qab tshuaj xyuas cov lus tawm (muab los ntawm lwm tus neeg siv khoom).

Tam sim no cia ua piv txwv:

Kuv feem ntau ua haujlwm nrog digital logic circuits/Microcontroller cuam tshuam txog cov khoom siv uas xav tau feem ntau 5v/max 2A (yog tias kuv siv qee lub cav & khoom zoo li ntawd).

Kuj qee zaum, kuv ua haujlwm ntawm Cov kab hluav taws xob uas xav tau ntau npaum li 30v/3A & kuj tseem muaj ob qho khoom siv. Yog li kuv yuav xaiv cov khoom siv uas tuaj yeem muab qhov siab tshaj 30v/3A thiab muaj cov tshuab hluav taws xob sib cais ob. 30v/3A thiab lawv yuav tsis muaj ib qho kev tsheb nqaj hlau GND lossis VCC tsheb nqaj hlau). Kuv tsis tas yuav xav tau ib tus lej zoo nkauj zoo li qub! yuav xaiv lub zog xa khoom raws li kuv cov lus tau hais los saum no …

Kauj Ruam 4: Kuv Lub Hwj Huam Muab…. Rigol DP832

Yog li raws li kuv xav tau, Rigol DP832 yog cov cuab yeej siv tau zoo tshaj plaws rau kuv siv (NTAWV, TSEEM NYOB ZOO TSHAJ PLAWS HAUV Kuv Lub Tswv Yim).

Tam sim no cia peb ua tib zoo saib nws muaj Peb txoj kev sib txawv. C. Ch1 & Ch2/3 yog hluav taws xob sib cais. C. Ch1 & Ch2 tuaj yeem muab ob qhov siab tshaj ntawm 30v/3A. Koj tuaj yeem txuas lawv ua ke kom tau ntau npaum li 60v (max tam sim no yuav yog 3A). Koj tseem tuaj yeem sib txuas sib txuas tau lawv kom tau txais qhov siab tshaj ntawm 6A (qhov siab tshaj plaws yuav yog 30v). Ch2 & Ch3 muaj qhov sib thooj. Ch3 tuaj yeem muab qhov siab tshaj ntawm 5v/3A uas tsim nyog rau digital circuits. Cov tag nrho cov zog tso tawm ntawm tag nrho peb txoj kev sib koom ua ke yog 195w nws raug nqi kuv ib ncig 639 $ hauv Is Nrias teb (Ntawm no hauv Is Nrias teb, nws yog tus nqi me ntsis piv rau Rigol qhov chaw uas nws tau hais txog ntawm 473 $ vim tias kev them nqi thiab tax..)

Koj tuaj yeem xaiv cov channel sib txawv los ntawm nias lub 1/2/3 khawm kom xaiv cov channel sib xws. Each tus kheej channel tuaj yeem On/Off siv nws cov hloov pauv sib xws. Kuv tseem tuaj yeem tig lawv On/Off tag nrho ib zaug ntawm lwm qhov kev hloov tshwj xeeb hu ua Txhua on/off. The tswj interface yog digital nws muab tus lej lej rau nkag ncaj qha ntawm ib qho kev muab hluav taws xob/tam sim no. Kuv tseem muaj tus lej nkag teb chaws uas koj tuaj yeem maj mam nce/txo ib qho kev ntsuas.

Volt/Milivolt/Amp/Miliamp - plaub tus yuam sij muaj nyob rau hauv kom nkag mus rau qhov chaw xav tau. Kuv tseem siv cov yuam sij no kom txav tus cursor Sab saum toj/Hauv qab/Txoj Cai/Sab laug.

Muaj tsib tus yuam sij nyob hauv qab cov zaub uas ua raws li cov ntawv uas tau qhia hauv cov duab saum toj no cov hloov pauv. qhib OVP.

Lub zog hluav taws xob muaj OVP (dhau kev tiv thaiv hluav taws xob) & OCP (dhau kev tiv thaiv tam sim no) rau txhua tus channel.

Piv txwv tias, kuv xav khiav lub Circuit (uas tuaj yeem tiv taus qhov siab kawg ntawm 5v) qhov twg kuv yuav maj mam nce qhov hluav taws xob los ntawm 3.3v txog 5v. Tam sim no yog tias kuv yuam kev tso hluav taws xob ntau dua 5v los ntawm tig lub pob qhov rooj & tsis saib ntawm cov zaub, Tam sim no hauv qhov xwm txheej no OVP los rau hauv kev ua haujlwm. Kuv yuav teeb tsa OVP rau 5v. Tam sim no kuv yuav maj mam nce qhov hluav taws xob los ntawm 3.3v thiab thaum twg los txog 5v txwv, cov channel yuav raug kaw los tiv thaiv lub nra.

Ib yam mus rau OCP. Yog tias kuv teeb tsa tus nqi OCP (Rau hais 1A), thaum twg tam sim no kos los ntawm lub nra mus txog qhov txwv, cov zis yuav raug muab tua.

Nov yog qhov muaj txiaj ntsig zoo los tiv thaiv koj tus qauv tsim muaj txiaj ntsig.

Tsis tas li ntawd muaj ntau yam ntxiv uas kuv yuav tsis piav tam sim no. Rau hais, muaj lub sijhawm uas koj tuaj yeem tsim qee qhov kev hloov pauv zoo li lub xwmfab/sawtooth thiab lwm yam.

Kuv muaj tus qauv daws teeb meem qis uas txhawb kev nyeem rov qab ntawm ib qho hluav taws xob/tam sim no mus txog ob qhov chaw zauv. Rau Ex: Yog tias koj teeb nws rau 5v thiab tig cov zis tso tawm, cov duab yuav qhia koj 5.00 thiab zoo ib yam rau tam sim no.

Kauj Ruam 5: Txaus Siab Tham, cia Lub Hwj Chim Qee Yam Ntxiv (tseem, CV/CC Hom Rov Ntsuam Xyuas!)

Tam sim no nws yog lub sijhawm los txuas lub nra thiab txhawb nws.

Saib thawj daim duab uas kuv tau txuas kuv lub tsev dummy load rau hauv channel 2 ntawm lub zog siv.

Dab tsi yog Dummy load:

Dummy load yog qhov pib hluav taws xob uas rub tawm tam sim no los ntawm ib qho khoom siv hluav taws xob. Tab sis hauv lub nra hnyav (zoo li Lub Teeb/lub cev muaj zog), kev siv tam sim no tau tsau rau tshwj xeeb Noob/Tsav. kho qhov teeb meem tam sim no los ntawm lub lauj kaub piv txwv li peb tuaj yeem nce/txo lub zog siv raws li qhov peb xav tau.

Tam sim no koj tuaj yeem pom meej tias lub nra (lub thawv ntoo ntawm sab xis) tab tom kos 0.50A los ntawm cov khoom siv. Tam sim no cia peb saib lub zog tso saib. Lub xwmfab ntsuab nyob ib puag ncig channel2 & txhua qhov kev ntsuas tsis zoo ib yam li qhov hluav taws xob, tam sim no, lub zog tawm los ntawm lub zog tau pom). Nws tab tom qhia qhov hluav taws xob li 5v, tam sim no li 0.53A (uas yog qhov tseeb & kuv dummy load tau nyeem tsawg dua piv txwv li. 0.50A) & tag nrho lub zog faib tawm los ntawm kev thauj khoom piv txwv li 2.650W.

Tam sim no cia saib lub hwj huam hluav taws xob tso tawm ntawm daim duab thib ob ((zoomed pic ntawm cov zaub). Kuv tau teeb hluav taws xob ntawm 5v & qhov siab tshaj tam sim no tau teeb tsa ntawm 1A. Lub ntsiab lus no, lub nra yog nqus 0.53A uas tsawg dua qhov teeb tsa tam sim no 1A yog li lub zog siv tsis txwv qhov tam sim no thiab hom yog CV hom.

Tam sim no, yog tias tam sim no kos los ntawm kev thauj mus txog 1A, cov khoom siv yuav nkag mus rau CC hom thiab txo qhov hluav taws xob kom tswj tau qhov tsis tu ncua 1A tam sim no ntawm qhov tso tawm.

Tam sim no, txheeb xyuas daim duab thib peb ntawm no koj tuaj yeem pom tias lub dummy load tau teeb duab 0.99A. Yog li hauv qhov xwm txheej no, lub zog siv hluav taws xob yuav tsum txo qis qhov hluav taws xob & ua kom muaj zog 1A tam sim no ntawm qhov tso tawm.

Wb saib ntawm daim duab 4 (zoomed pic ntawm cov zaub) uas koj tuaj yeem pom tias hom tau hloov pauv mus rau CC. Qhov fais fab tuag tau txo qhov hluav taws xob mus rau 0.28v kom tswj tau qhov thauj khoom tam sim no ntawm 1A. Again, ohm txoj cai yeej !!!!

Kauj Ruam 6: Cia Kom Muaj Kev Lom Zem…. Lub Sijhawm Los Xeem Qhov Tseeb

Tam sim no, ntawm no yog qhov tseem ceeb tshaj plaws ntawm ib qho khoom siv hluav taws xob piv txwv li Qhov raug. Yog li hauv ntu no, peb yuav tshuaj xyuas, qhov tseeb ntawm hom khoom siv hluav taws xob programmable yog li cas tiag !!

Kev ntsuas qhov ntsuas qhov tseeb:

Hauv thawj daim duab, Kuv tau teeb tsa lub hwj chim rau 5v & koj tuaj yeem pom tias kuv nyuam qhuav ntsuas tau Fluke 87v Multimeter tau nyeem 5.002v.

Tam sim no cia saib cov ntaub ntawv ntawm daim duab thib ob.

Qhov ntsuas qhov tseeb rau Ch1/Ch2 yuav nyob hauv thaj tsam raws li tau piav qhia hauv qab no:

Teeb qhov hluav taws xob +/- (.02% ntawm Teeb qhov hluav taws xob + 2mv). Hauv peb qhov xwm txheej, Kuv tau txuas Multimeter rau Ch1 & teeb hluav taws xob yog 5v.

Yog li qhov txwv qis tshaj ntawm qhov hluav taws xob tso tawm yuav yog:

5v + (.02% ntawm 5v +.002v) piv txwv li 5.003v.

& qhov txwv qis rau qhov tso zis hluav taws xob yuav yog:

5v - (.02% ntawm 5v +.002v) piv txwv li 4.997.

Kuv qhov ntsuas tam sim no Fluke 87v Industrial standard Multimeter tau qhia txog 5.002v uas yog nyob hauv qhov tshwj xeeb tau teev tseg raws li peb tau suav sau saum toj no. Qhov txiaj ntsig zoo heev kuv yuav tsum hais !!

Kev ntsuas qhov tseeb tam sim no:

Ib zaug ntxiv saib cov ntaub ntawv rau qhov tseeb tam sim no. Raws li tau piav qhia, qhov tseeb tam sim no rau tag nrho peb txoj kev yuav yog:

Teem tam sim no +/- (.05% ntawm teeb tsa tam sim no + 2mA).

Tam sim no cia saib ntawm daim duab thib peb uas kuv tau teeb tsa qhov siab tshaj tam sim no rau 20mA (Lub zog siv hluav taws xob yuav nkag mus rau CC hom thiab sim tswj 20mA thaum kuv yuav muab Multimeter) & kuv Multimeter nyeem ntawv 20.48mA.

Tam sim no cia peb xam qhov ntau ua ntej.

Qhov txwv qis tshaj ntawm cov zis tam sim no yuav yog:

20mA + (.05% ntawm 20mA + 2mA) piv txwv li 22.01mA.

Qhov txwv qis tshaj ntawm cov zis tam sim no yuav yog:

20mA - (.05% ntawm 20mA + 2mA) piv txwv li 17.99mA.

Kuv ntseeg Fluke tau nyeem 20.48mA & dua tus nqi yog nyob rau thaj tsam saum toj saud. Ntawm peb tau txais txiaj ntsig zoo rau peb qhov kev ntsuas raug tam sim no. Qhov fais fab tuag tsis ua rau peb ….

Kauj Ruam 7: Qhov Kev Txiav Txim zaum kawg …

Tam sim no peb tau los txog rau ntu kawg…

Vam tias kuv tuaj yeem muab tswv yim me me rau koj txog cov khoom siv hluav taws xob uas tuaj yeem tsim tau thiab lawv ua haujlwm li cas.

Yog tias koj mob siab rau hluav taws xob thiab ua qee qhov tsim qauv loj, Kuv xav tias txhua yam ntawm cov khoom siv hluav taws xob uas tsim nyog tau yuav tsum muaj nyob hauv koj lub tsev txhab nyiaj vim tias peb tsis nyiam ua kib peb cov qauv tsim muaj txiaj ntsig vim qee qhov yuam kev overvoltage/overcurrent/luv Circuit Court.

Tsis tsuas yog qhov ntawd, tab sis kuj nrog cov khoom siv no, peb tuaj yeem them nqi txhua hom Li-po/Li-ion/SLA roj teeb yam tsis ntshai ntshai tua hluav taws/ib qho tshwj xeeb charger (Vim Li-po/Li-ion roj teeb yog nquag mus tua hluav taws yog tias qhov ntsuas tsis raug them tsis tau raws!).

Tam sim no nws yog lub sijhawm los hais lus zoo!

Yog tias koj xav tias Phau Ntawv Qhia no tshem tawm ib qho ntawm peb qhov kev ua xyem xyav thiab yog tias koj tau kawm qee yam tawm ntawm nws, thov muab ntiv tes xoo & tsis txhob hnov qab sau npe!

Zoo siab kawm….

Ua tsaug !!