JOURNAL OF SCIENCE OF HNUE Interdisciplinary Sci , 2014 Vol 59, No 1 pp 37 49 NGHIEN CUU NGUYEN TAC CAU TAO VA HOAT DONG CUA AMPE KE VA VON KE THEO CON D U 6 N G T H I ^ T KE TRONG DAY HOC VAT LI 6 L[.]
JOURNAL OF SCIENCE OF HNUE Interdisciplinary Sci., 2014 Vol 59, No pp 37-49 NGHIEN CUU NGUYEN TAC CAU TAO VA HOAT DONG CUA AMPE KE VA VON KE THEO CON D U N G T H I ^ T KE TRONG DAY HOC VAT LI L P II TRUING TRUNG HOC PHO THONG Nguyen Ngpc Hting Khoa Vdi li, Trudng Dai hoc Suphgm Hd Npi Tom tat Bai bao trinh bay viec to chflc cho hpc sinh ldp 11 nghien cflu nguyen tac cau tao, hoal dong cua ampe kl va vdn kl theo cac giai doan cua dUdng thill kl nham phat buy linh tich cUc, phat trien nang lUc sang tao ciia hoc smh Tit khda: Ampe ke von ke, day hoc Vai li Vat li 11, dudng thill ke, tich cUc, sang tao Mot dau L/ng dung ki thuat ( U D K T ) ciia vat li la mdt nhflng loai kiln thflc cd ban ma hpc sinh (HS) cln linh hpi hoc tap vat li d trudng phd thdng Day hoc UDKT cua vat li dupe tien hanh theo hai dUdng: I/Tim hieu ban than thill bi ki thuat (TBKT), nguyen tac cau tao, boat dpng cua nd va di tdi lam sang td cd sd vat li cfla TBKT (con dudng I) hoac 2/ hUdng din HS dfla tren nhflng kiln thflc, ki nang da cd thilt kl, chi tao TBKT ed mpl chflc nang nao dd (dap flng dupc mpl yeu clu ki thuat xac dinh) giai quylt mot nhiem vu cu the san xuat va ddi sdng (con dudng 2- dudng thilt kl) Viee nghien cflu UDKT cua vat li theo eon dfldng cd lac dung rat Idn doi vdi viec phat trien tfl khoa hpc - ki thuat cua HS Ampe kl va vdn kl la nhflng dung cu (DCD) dupc HS sfl dung Ihudng xuyen irong cac thi nghiem (TN) Viec dl cap nguyen lac cau tao va hoat ddng cfla chung la can thilt Day la L/DKT cua vat li phu hdp de td chflc cho HS nghien cflu iheo dfldng ciia day hpc UDKT cfla vat 11 2.1 Npi dung nghien CIJ:U Tien trinh nghien ciiu chung cua HS ve nguyen tac cau tao, hoat dong cua ampe ke va von ke Dua vao tiln trinh chung nghien cflu mpl L/DKT cua vat li theo dudng liln trinh nghien cflu cfla IIS ve nguyen tac cau lao hoal ddng cua ampe kl va vdn ke diln Ngay nhan bill, 15/07/2013 Ngay nhandang 15/12/2013, Lien he- Nguyen Ngoc Hung, e-mail nnhung67hb@yahoo com Nguyin Ngoc Hung theo cac giai doan sau: 2.1.1 Lam sinh van de can giai quyet - Tren cd sd nghien cflu li thuyet va thflc nghiem ve viec mSc dien kl (G) vao doan mach dien can 1, U, di tdi nhan xet: G cd gidi han (GHD) I, U xac dinh va vi G co dien trd nen viec mac G vao doan mach dien lam giam gia tri I, U can - Tfl dd, sinh vin dl (VD) cSn giai quylt la: Cd each nao de lam giam anh hUdng cua G den phep I, U mac G vao doan mach dien va md rdng dUpc GHD I, II cfla G? 2.1.2 Suy doan va thflc hien giai phap giai quyet van de (GQVD) Bang lap luan (suy doan giai phap - SDGP) va sau dd, tinh toan cu the (thUc hien giai phap - THGP) tfl cac kiln thflc da biet vl mach dien mdt chilu, di tdi cSu tra Idi cho ca cau hdi tren: - can mac sdn (s) song song G biln nd ampe kl va can mac dien trd phu (Rp) ndi tiep vdi G, bien nd vdn ke - Mudn GHD I(U) cua G tang len n(m) Ian ihi s mac song song G phai cd Ry ^ — ^ va Rp mac noi tiep G phai ed Rp = (m - 1) Rj, 2.1.3 Kiem nghiem nhoi TN tinh diing dan cua ket luan da rut ve viec lam tang GHD cua G - Dua vao cac bieu thflc tren, cho bill Rg, tinh gia tri R,(Rp) can mac song song (noi lilp) vdi G de biln G ampe kl (von kl) cd GHD I (U) gip n (m) Ian GHD I(U) cua G va tinh cac gia tri lo(Ug) Ung vdi cac gia tri I.^(U\) khac - Thiet ke mach dien va tiln hanh TN de xac nhan cac gia tri Ir,{Up) da tinh dUOc tfl cac bieu thflc 2.1.4 Lam sinh VD can giai quyet tiep Vl moi s (moi R^) mac song song (noi tilp) vdi G cd gia tri R.s(Rp) nhat dinh nen GHD 1(U) cua G chi dflpc tang len tdi mdt gia trj xac dinh VD cin giai quylt tiep la: Lam thi nao de GHD I(U) cua G dupc md rpng tdi cae gia tri khac nhau, nghia la ampe kl (vdn kl) cd nhilu thang khac nhau'' 2.1.5 Suy doan va thiTc hien giai phap GQVD - Dfla vao cae bieu ihflc tinh H, va Rp, dua giai phap: Mudn ampe kl (vdn ke) cd nhilu thang khac ihi phai mac song song (ndi tiep) vdi G cac s (cac Rp) cd R^Rp) khac - Thilt kl cac mach dien noi G song song vdi cac s (d ampe kl) cho R, thang Idn hdn R, d thang dd thfl hai dl GHD I dung thang thfl nhat nhd hdn GHD I dung thang thfl hai cua ampe kl va ihilt kl cac mach dien ma cac Rp dUdc mic ndi lilp vdi G (d vdn kl) cho Rp d ihang thfl nhat nhd hdn R^ d thang thfl hai de 38 Nghien ciiu nguyen tdc cdu lao vd hoal ddng cua ampe kS vd vnn ke GHD U dung thang thfl nhat nhd hdn GHD U dung thang thfl hai cua vdn kl 2.1.6 Kiem tra tinh dung dan cua cac ket luan da rut tren DCD Md rnat sau cua ampe ke (vdn kl) thflc hanh de xac dinh each mac cac s (cac Rp) vdi G va khang dinh tinh dung dan cua cac kit luan da nit 2.2 Cac giai doan nghien ciiu nguyen tac can tao va hoat dong cua ampe ke theo ditcfng thiet ke 2.2.1 Nghien cu:u li thuyet va thuc nghiem ve G thuc hanh cudng dong dien (I) de lam xuat hien VD can giai quylt (Lam thi nao de lam giam anh hfldng cua G den gia tn I cln mac nd vao mach dien can I chay qua va md rdng dUdc GHD I cua G?) Hinh l.Gdo\ (a) vd mach dien cda G (b) - Tim hieu G I (Ifmh la): DUa vao quan sat mat ngoai va ben irong G, hay xac dinh chflc nang (do I mdt chilu) kieu cd cau (kieu tfl dien bang khung quay), mach dien cua G (Hinh lb), cac thdng sd ciia G: cac thang (khi dung hai chdt ( - ) va (OQ) hay ( - ) va (GO, G cd cung mdt thang -3aO/j.A - ~ 300//A), GHD (Imax = 300//A) gia iri cua moi dp chia tren tflng Ihang (1()//A}, cap chinh xac ciia G (sai so he Ihdng ciia phep I G gay ra), chilu quay cua kim chi flng vdi tflng trfldng hdp Giao vien (GV) bd sung Ddn vi I (khdng dupc ghi tren mat G) la /tA sfl dung G d hai chdt ( - ) va (Go) tiln hanh TN de phat hien gay bdi cac U nhd nhu ddng nhiet dien, ddng cam flng dien tu cdn d hai chdt ( - ) va (G i) tiln hanh TN de phat hien cac I nhd nhung U khdng nhd, nhfl mach cau Uytxidn Iflc chfla can bang - Nghien cflu li thuyet ve anh hfldng cua G den gia tri I can Ap dung dinh luai Om doi vdi loan mach (Hinh 2) dc thay rang: Viec mac G vao mach dien can I lam cho gia tri I dUdc sai lech (nhd hdn) so vdi gia tn thUc cfla I can (1 doc dudc tren -.- < Ith R -h r f R R-f r Nguyin Ngoc HUng Hinh Do I nhd G - Nghien cflu thUc nghiem ve anh hfldng cua G din gia tri I can do: Lap mach dien nhu Hinh Dich chuyen biln trd de thay ddi UAB- Lfng vdi mdi UAB fJoc sd chi cfla Gi chfla mac G2 va mac ca Gi va G2 vao doan mach AB, de thay S6 chi cua Gi mac ddng thdi ca Gi va G^ ludn nhd hdn sd chi cua Gi chi mac Gi IHinh Kiem nghiem dnh hudng cua G den I can Nhfl vay, nghien cflu II thuyet va thflc nghiem deu din tdi nhan xel: Khi mac G vao mach dien can I, G da lam giam gia trj I can do, gay sai so cfla phep I va mdi G chi cd mdt GHD lo xac dinh VD can giai quylt la: Lam thi nao de lam giam anh hudng cua G den phep I (lam giam sai sd cfla phep I) dung G va cd each nao de cd the sfl dung G dfldc I cd cfldng dp Idn hdn IQ (tflc la md rpng dfldc GHD cua G)'' 2.2.2 Suy doan va thuc hien giai phap GQVD nhb suy luan li thuyet (SLLT) tuf cac kien thufc da bict - Suy doan giai phap GQVD + Tfl bieu thflc I = : - ^ , thay: De lam giam anh hudng cua G din gia tn can do, phai lam giam Rg, cho Rg < R Lfng vdi G da cho (R^ nhlt dinh), cd the lam giam R DCD (DCD) bang each mac dien trd phu song song vdi G + Cung cd the sfl dung giai phap mac dien trd phu song song G de chi mdt phln ddng dien chay qua G, !„ khdng vUdt qua lo, phan ddng dien cdn lai {I - IQ) di qua dien trd phu (chia dong) Nhd ma DCD cd the dUdc I > I,, - Thuc hien giai phap da suy doan Ap dung dmh luat Om cho doan mach mac song song cac dien trd mac dien trd phu (cdn gpi la sdn) song song vdi G, biln nd ampe kl (Hinh 4), cd R^R -RA - , thay RA < Rg, RA < R.: s lam giam R cfla DCD va dd, lam R^ + R,' sai sd cfla phep nhd di Nghien cdu nguyen tac cdu tao vd hoat dong cua ampe ke vd vnn ke Hinh Cdu tao cua ampe ki cua G, lam cho ampe kl dfldc I^ax gap >i lln in td' da ma G dUdc I + Muon GHD I cua G tang len n Ian (n ) thi s mac song song vdi G phai cd R, + NIU R^ cang nhd so vdi Rg thi RA cang nhd, anh hudng cua DCD den gia iri cln cang nhd va GHD (n) cua ampe kl cang Idn 2.2.3 Kiem nghiem nhd TN tinh dung dan cua ket luan da rut ve vice lam tang GHD cua G bang each mac s song song v6i G - Dua vao bieu Ihflc linh R^, tim dd Idn K, phai mac song song vdi G da lim hieu dung hai chdi ( - ) va (G|) debien G ampe kl cd GHD \„^,,^ ^- 3()mA cho biel Rj = lOOfi, Ro = 2400n? (Vi R^ = - , biel diing hai chot (—) va (Gi) thi Rj = RG -I- Rii = 2600n 1A„„;, = 30mA lg„„„ = 300;/A nen R^ = 6f!) - Difa vao bieu thiJc 0, 2A, la,, = 0,3A va IAJ U —, tinh cac gia tri iJng vdi l,\i O-IA 1A2 ^ - 0, lA Hinh Kiem nghiem cdc gid tri l^ dd tinh dttoc ' Thiel ke mach dien va tien hanh TN de kiem nghiem cac gia tn Ig da linh duoc 111 li thuyet: Lap mach dien nhlt Hinh 5, G duoc diing vdi hai chfil ( ) va ( d ) , R dllcJc tao nhd dien trd cd cac vach mau de tien hanh TN kiem nghiem cac gia tri 1,, da tinh diJOc Cac day noi phai cd dien trd nhd Kgt qua TN cho IhSy Cac Ij, doc dUdc tren G 41 Nguyen Ngpc Hung trung vdi cac Ig da tinh dUdc - Nlu vSn dung mat chia dp cua G I lam mat chia dp cua ampe kl mdi dUdc tao bdi G va s da mac, xac dmh thang mdi va gia tri cua mdi chia tren thang nay? (Vi I = nig nen sau mac them s cho G, neu vSn dung mat chia dp cua G de dpc I dUdc thi phai chia lai thang chia dp, mdi dp chia tren mat chia dp cua G cd gia tn Idn gap n Iln (100 Ian) gia tri cua mdi dp chia khdng mac them s vao G (Gia tn cua mdi dp chia tren thang mdi la mA) 2.2.4 De xuat VD can giai quyet tiep - Cng vdi I s ( R^ nhlt dinh) mac song song vdi G, GHD I cua G chi dflpc md rpng tdi mot gia tri I xac dinh (n xac dinh) Vay lam thi nao de GHD I cua G dfldc md rdng tdi cac gia tri I khac nhau, nghia la ampe ke cd nhieu thang do? - Vl du nhfl: Lam thi nao de GHD cua G I da tim hieu dfldc md rpng tdi hai gia tri I khac (ampe kl se cd hai thang khac nhau)? 2.2.5 Suy doan va thuc hien giai phap GQVD - Muon G dupc md rdng GHD tdi cac gia tri I khac thi phai mac song song vdi G cac s cd R^ khac - Neu muon G I da lim hieu cd the dudc hai Imax khac thi mac cac sdn si va s2 khac song song vdi G theo Hinh 6: Hinh Ampe ke co thang + Khi dung hai chdt ( - ) va (I): (G ndi tilp RO) // (Rsl ndi tilp Rs2) + Khi dflng hai chdt ( - ) va (2): (G noi tilp RQ ndi tilp Rs2)//Rsl Vi RA dung hai chot ( - ) va (1) Idn hdn RA dung hai chdt ( - ) va (2) nen GHD 11 dung hai chdt ( - ) va (1) nhd hdn GHD 12 cua ampe kl dung hai chdt ( - ) va (2) 2.2.6 Kiem tra tinh dung dan cua ket luan da rut b ampe ke thUc hanh va tim hieu cac thong so cua nd - Md mat sau cua ampe kl thflc hanh de xac dinh each mic cac s vdi G va khang dinh tinh dflng dan cua giai phap da dl x u l t GV bd sung thdng tin ve cac gia tri Rg =^ -'lS^R(i = 3i2.R^i - 0,030 vaR^2 - 0,12ii - Dfla vao quan sat mat ngoai cua ampe kl (Hinh 7), xac dinh chflc nang (do I mot chieu) kieu cd clu (kieu tfl dien), cac thdng sd cua ampe kl: Cac thang do, GHD Nghien cdu nguyen tdc cdu tao vd hoat ddng ciia ampe ke vd vdn ke Hinh Ampe ke thUc hanh sfl dung cac chdt tren ampe kl, gia ui I cfla mdi dp chia tren tflng thang va tra Idi eac cau hdi: Khi nao thi I can cd gia tri dUdng cd gia tri am'^ Bill d p chinh xac cua ampe kl la 2.5, tinh sai sd he thong cfla phep do ampe ke gay flng vdi mdi thang (Ampe kl cd hai thang do' dung hai chot ( - ) va (0.6A), ampe kl ed thang - , A - - 0, 6A, GHD la GA, gia tri cfla mdi dp chia la 0, 02A; cdn dung hai chot ( - ) va (3A) ampe kl co thang do: -\A -0 - 3.1 GHD la 3A gia tri cfla mdi dp chia la U, lA Vach cua ampe ke khdng d gifla cac thang Cudng dp cln se mang gia iri dUdngkhi di vao cac chdi (l),(iA) va (:iA) 2.3 Cac giai doan nghien cu'u nguyen tac cau tao va hoat dong cua von ke theo dirbng thiet kc 2.3.1 Nghien cu'u li thuyet va Ihuc nghiem ve dien ke thuc hanh hieu dien the dc lam xuat hien VD can giai quyet (Lam the nao de lam giam anh hudng cua dien kl den gia in hieu dien thi cln mac nd vao hai dau doan mach va md rpng dUde GHD hieu dien the cfla G ?) - Vi nen ngoai viec dung G 1, cd the dung G de U bang each ghi U lfldng Ung vao cac vach tren thang chia dp cua G Neu dflng G da lim hieu (Ifinh 1) de U thi G se cd may ihang U ? Ve cac ihang dd cd ghi cac gia tri U lUdng flng thay cho cac gia tri Id cac vach chia tren G doi (Vi Uc;„ - 1R(;-Uc;i ~- IR, -• l(Rc; i Ro) da bilt R(! va Ri) nen neu dung G I da tim hicu de U thi G cd hai ihang do: + Khi dung hai chdt ( —) va (GQ) ' -3niii\' - - 3()ni\' Gia in cua mdi dp chia la liiiW + Khi dung hai chdi (—) va (GI) • -750iiiV - - 750niV Gia tri cua mdi ddchia la 2r.niV - Ddi chilu cac thang da ve vdi cac thang d mat ngoai cua G V dc kiem tra du doan vl cac ihang (Thang d mat ngoai cfla G dung nhu thang da dfl doan) va cdn thay Tren mat ngoai cua G U (Hinh 8) chi ghi gia tri cua cac vach chia flng vdi Nguy€n Ngpc Hung Hinh Dien ki thifc hanh U thang sil dung hai chdt ( - ) va (Go), khong ghi ddn vi (mV) - DUa vao quan sat mat ngoai cua G U hay xac dinh them cac thong tin: ChiJc nang (Do U mot chieu), kieu CO cau (Kieu til dien) cSp chinh xac (sai so he thong ciia phep U G gay ilng vdi tilng thang do), chiju quay ciia kim chi ling vdi tilng trudng hop - Nghien ciiu h' thuyet ve anh hudng ciia G den gia tri U can (Hinh 9): Ap dung dinh luat m ddi vdi loan mach chua mac G va mac G de thay rang: Viec mac G II giOa hai dau doan mach AB lam cho gia tri U' dUdc sai lech (lam giam) so vdi gia tri thuc cua U can (Hieu diun the doc duoc tren G mac G vao doan raach AB Hinh Do II nhil G fRR, + (R + R.) R t R the chua mac G U = £RR, RR + \(Y ¥ R,, < hieu dien R1 R) R -t- r - Nghien ciiu thifc nghiem ve anh hudng ciia G den gia In (J can do: Liip mach dien nhil Hinh 10 Dich chuyen bi€n trd de thay ddi UAB t'ng vdi mdi UAB, Ian lUdt doc s6 chi ciia Gi chi mac Gi va mac dong thdi Gi va G^ vao doan mach AB de thay: So chi ciia G1 miic ca G1 va Gy ludn nhd hdnsdchiciiaGi chi mac Gj Nhu viiy, vice nghien ciiu li thuyet va thuc nghiem deu din tdi nhan xef Khi mac G vao hai dau doan mach can II G dii lam giam gia tn U c&n do, gay sai sd ciia phep U vii mdi G chi cd mdt GHD Uo xiic dinh 44 Nghien ciht nguyen tdc cdu tao vd hogi ddng cua ampe ke vd vdn ke ^Sy U^ U^i^- Hinh 10 Kiem nghiem dnh hudng cua G den U cdn VD can giai quyet la: Lam the nao de lam giam anh hudng cua G din phep U (lam giam sai sd cua phep L') mac G vao hai dau doan mach cln U va cd each nao de cd the sfl dung G dfldc U cd gia tri Idn hdn UQ, tflc la md rdng dUde GHD cua G? 2.3.2 Suy doan va thuc hien giai phap GQVD nhd SLLT tfl cac kien thflc da biet - Suy doan giai phap GQVD: + Tfl bieu thflc U -R rR R+ r+ - ta Ihay; De lam giam anh hfldng cua G din gia tri U cln phai lam iang R„ cho Rg > R iJng vdi G da cho (R,; nhlt dmh), cd the mac dien trd phu ndi lilp vdi G DCD Nhd dd R DCD se tang len + Cung cd the sfl dung giai phap mac dien trd phu noi tilp vdi G irong DCD de chia mdt phln hieu dien thi dat vao hai dau AB cua doan mach, lam cho L\ khdng vudi qua gia tri Ud phln hieu dien thi cdn lai (U - Uo) dfldc dat vad dien ird phu (chia ihl) Nhd dd DCD cd the dfldc U > (IQ - Thflc hien giai phap da suy doan: Ap dung dinh lual Om cho doan mach mac ndi tilp cac dien ird mlc dien trd phu ndi tilp vdi G biln nd vdn ke (Hinh 11) cd: Hinh 11 Cdu tao eiia Von he + Rv - RA + Rp' ^hay: R\- > R R\' > R,,; dien trd phu lam iang dien trd cua DCD va dd, lam sai sd cua phep U nhd hdn Uv = I + p'; ) U, = luU, Nguyin Ngpc Hung (m : he sd md rdng thang do, >1), thSy: Rp lam tang GHD cua G liun cho vdn ke duoc Umax gap m I™ Uii toi da ma G diroc + Mudn GHD U cua C tang len m Ian (m = -~) tU dien trd phu mac noi tiSp vdi G phiii cd R.p ^ [m - l)Rg + Neu Rp cang Idn thi Rv cang Idn, anh hudng ciia DCD ddn gia tri U can cang nhd va GHD (m) cua vdn ke cang Idn 2.3.3 Kiem nghiem abb TN tinh diing dan cua kit luan da rilt ve viec lam tang GHD cua G bang each mac Rp noi tiep vdi G - Dua vao bieu thiic tinh U\- tim Idn Rp phai mSc noi tiep vdi G U dung hai chdt ( - ) va (G„) de biSn G vdn ki cd GHD U„,,^ la 3V, da biSt diing hai - I R biet Uvmax = 3V, Ujm^ diing Us hai chot ( - ) va (Go) lii 30niV R, = lOOf! nen Rp = 9900!!) chdt Rj = 100! i? (Vi Rp = - Dua vao bieu thiic U, = — , tinh cac gia tri U iing vdi Uvj = IV, Uv2 = ^ m 3V,Uv.i = 2VvaUv4 = -IV Ilinh 12 Kiem nghiem cdc gid tri \]^ dd tinh dUdc - Thilt kl mach dien va tiln hanh TN de kiem nghiem cac gia trj U^ da tinh dudc Ifl li thuyet Lap mach dien nhfl Ifinh 12^ dd G dudc dung vdi hai chot ( - ) va (Go) va Rp dfldc tao nhd dien trd cd cac vach mau de tiln hanh TN kiem nghiem cac gia tri L'^ da tinh dfldc Cac day ndi phai cd dien trd nhd Kit qua TN cho thay: Cac U^ dpc dfldc tren G trung vdi eac l'^ da tinh dflpc - NIU van dung mat chia dd cua G U lam mat chia dd cua von kl mdi dUdc tao bdi G dung hai chdt ( - ) va (Go) va dien trd phu R.,, da mac, xac djnh thang mdi va gia iri cfla mdi dd chia tren thang (Vi U\' ^ mUp nen sau mac Rp ndi tilp vdi G, nlu van dung mat chia dp cua G dc doc U dUdc thi phai chia lai thang chia dd, mdi dd chia iren mat chia dd cfla G cd gia tri Idn gIp m Ian gia tn cfla nd khdng mlc R,, vao G Gia tri mdi dp chia tren thang mdi la 0,1V) Nghien cdu nguyen tdc cdu tao vd hoal ddng ciia ampe ki v 2.3.4 De xual VD can giai quyet tiep - Cng vdi mdt dien trd phu (Rp nhat dinh) mac ndi tiep vdi G GHD U cua G chl dfldc md rdng tdi mdt gia tri U xac dinh (m xac dinh) Vay lam thi nao de GHD U cua G dflpc md rpng tdi cac gia tri U khac (vdn ke cd nhilu thang khac nhau)'' - Vi du nhfl: Lam thi nao de GHD U cua G U da tim hieu diing hai chot ( - ) va (Go) dUdc md rpng tdi gia tri U khac (vdn ke se cd hai thang khae nhau) ? 2.3.5 Suy doan va thUc hien giai phap GQVD - Mudn G dfldc md rdng GHD tdi cac gia tri U khac thi phai mac ndi tilp vdi G cac dien trd phu cd Rp khac - Nlu mudn G U dung hai chot (—) va (G(]) da tim hieu cd the dupc U,„ax l^ac thi cd the mac cac dien trd phu noi tiep vdi G theo cac each sau + Cach (Hinh I3a)' Khi dung hai chdt (—} va (1): Go noi tiep R^j, dung hai chdt (—) va (2): Go ndi tiep Rp2 Chpn R„i < Rp2 thi GHD U dung hai chot (- ) va (1) se nhd hdn GHD U dung hai chdt (—) va (2) + Cach (Hinh 13b): Khi dung hai chdt (- ) va (I): Go ndi tiep Rpi, dung hai chdt ( - ) va(2): Go ndi lilp Rp] noi tilp Rp2 GHD U dung hai chot ( ) va (2) se Idn hdn GHD U dung hai chot ( - ) va (1) 2 bl Hinh 13 Von ki ed thang 2.3.6 Kiem tra tinh diing dan cua ket luan da riit d von ke thUc hanh va tim hicu cac thdng sd cua nd - Md mat sau cua vdn ke thuc hanh de xac dinh each mac cac dien ird phu vdi Go, kie'm tra tinh dflng din cfla giai phap da dl xuat + Trong vdn kl thuc hanh cac Rp dfldc mlc ndi lilp vdi Go theo each cfla giai phap da neu + GV bd sung Ihdng dn vl cac gia tri Ra„ - 220^ Rp, = 'iyOOtl Rp Vimm vl each mlc cac dien trd phu theo each cfla giai phap da neu d mdi sd loai vdn kl thuc hanh khac - Dua vao quan sat mat ngoai cfla vdn kl (hinh 14) xac dinh chflc nang (do U mdt chieu), kieu cd cau (kieu tfl dien), cac thdng sd cfla vdn kl cac thang do, GHD sfl dung cac chdt tren vdn kc gia tri U cua mdi dp chia tren tflng thang Khi nao thi U Nguyin Ngpc HUng Hinh 14 Von ki thuc hanh can cd gia trj dUdng, cd gia tri am? Bill d p chinh xac cua vdn kl la 2,5, tinh sai so he thong cfla phep U vdn kl gay flng vdi mdi thang (vdn kl cd hai thang do: Khi dung hai chdt ( - ) va(3V): Go ndi tilpRpl, vdn kl cd thangdo la-1V-0-3V, GHD la 3V gia tri U cfla mdi ddchialaO.IV Khi dung hai chdt ( - ) va(15V) Go ndi tilp Rpl ndi tilp Rp2, vdn kl cd thang la -5V-0-15V GHD la 15V, gia tri U cua mdi dp chia la 0.5 V vdn kl nay, vach khdng d gifla cac thang do, I' can cd gia tri dUdng I di vao cac chot 3V I5V 2.4 Tom tat chii'c nang, nguyen tac cau tao va hoat dong cua DCDD GV hudng din HS tdm ta chflc nang nguyen tac hoat ddng cua dien kl ampe kl, vdn ke va bd sung mdt sd kiln thflc vl DCD cu the la: - Nguyen tac boat ddng cfla G: G la DCD boat ddng lac dung cfla ddng dien Vi U -^ I nen ngoai viec dung G doi, cdn cd the dung G de W ~ Sfl can thilt phai mac dien trd phu ampe ke vdn ke: Vi G cd dien trd va mdi G chi cd GHD U nhat dinh nen cln mac dien ird phu DCDD de giam sai sd cua phep I, U G gay va md rdng GHD I U cua G - Cach mac cac dien trd phu ampe kl vdn ke Trong ampe ke, cac sdn dUdc mac song song vdi G, cdn vdn ke thi cac dien trd phu dUdc mac ndi tilp vdi G - Cac bieu thflc tinh R,, (Rp) cln mac song song (ndi tiep) vdi G muon md rpng GIIDI U cuaG len n (m) Ian - Dp nhay cua DCD: Khi mlc them dien trd phu vao DCD, GHD cfla DCD dfldc tang len bao nhicu lln thi dd, cung mpl I (U), gdc lech cua kim chi DCD giam di biy nhieu lln, mdi dd chia tren mat chia dd cd gia tn Idn gap bay nhieu lln, nghia la dd nhay ciia DCD giam di bay nhieu lln Vi vay sfl dung DCD, phai chon thang phu hdp 4S Nghien cihi nguyen tdc cdu tao vd hoat ddng ciia ampe ke vd vdn ke cho gia tri I, U can khdng vUpt qua GHD va gdc lech cua kim chi DCD phai dfl Idn - Cap chinh xac cfla DCD: Khi sfl dung DCD, cac phep mac phai sai sd he thdng DCD gay Sai sd cd the U'nh dUde thdng qua cap chinh xac cua DCD, thudng dfldc ghi tren mat DCD Vi du nhu: Cap chinh xac cfla DCD (ampe ke vdn kl) la 2,5 thi cd nghia la cac phep vdi DCD mac phai sai sd bang 2,5% gia tri I, U Idn nhat cfla thang dang sfl dung - GV ed the td chflc cho cac nhdm HS ldp 11 nghien cflu nguyen tic cau tao, hoat ddng cua ampe kl, vdn ke gid hpc ngoai khda sau HS da hpc dien kl khung quay chUdng "Tfl trudng", dfldc coi la sU phat trien cac kiln thflc ma HS da thu dUdc vl dien ke GV chia ddi ldp, nfla ldp nghien cflu vl nguyen tac cau tao, hoat dpng cua ampe kl; nfla Idp cdn lai nghien cflu nguyen tac cau tao, boat ddng cua vdn ke va sau do, doi lai TAI LIEU THAM KHAO • [ ] Nguyin Ngpc Hung, 2011 Hai dudng day hpc cdc iing dung ki thudi ciia vai li day hpc vat li d trudng phd ihdng Tap chi Giao due Ha Ndi, So dac biet cudi nam [2] Nguyin Dflc Tham (chu bien), Nguyin Ngoc Hflng Pham Xuan Qui, 2002 PhuOng phdp day hoc vdt lid irudng phd thdng Nxb Dai hpc Su pham Ha Npi Jtesearch principles and operational structure of ammeter and voltmeter path design in teaching physics in 11*^ grade high school This paper presents the organization of study for students in 11*'' grades principles of composition, operation of ammeter and voltmeter in the stages of the path designed to promote the positive development of creative capacity students ... am''^ Bill d p chinh xac cua ampe kl la 2.5, tinh sai sd he thong cfla phep do ampe ke gay flng vdi mdi thang (Ampe kl cd hai thang do'' dung hai chot ( - ) va (0.6A), ampe kl ed thang - , A - -... ngoai cua ampe kl (Hinh 7), xac dinh chflc nang (do I mot chieu) kieu cd clu (kieu tfl dien), cac thdng sd cua ampe kl: Cac thang do, GHD Nghien cdu nguyen tdc cdu tao vd hoat ddng ciia ampe ke... hai chdt ( - ) va (2) nen GHD 11 dung hai chdt ( - ) va (1) nhd hdn GHD 12 cua ampe kl dung hai chdt ( - ) va (2) 2.2.6 Kiem tra tinh dung dan cua ket luan da rut b ampe ke thUc hanh va tim hieu