Thiết kế bài giảng vật lí 12 nâng cao tập 2

TRAN THUY HANG - HA DUYEN TUNG THIET KE BAI GIANG NANG CAO TAP HA! NHAXUATBANHANOI TRAN THUY H A N G - H A DUY£N TUNG THIET KE BAI GIANG lAVt NANG CAO - TAP ^ V- ? NHA XUAT BAN HA NOI CHWONG V DONG DIEN XOAY CHIEU • BAI26 DONG DifiN XOAY CHlfiu MACH DifiN XOAY CHlfiu CHI CO DifiN TRO T H U A N I-MUCTlfiU Ve kie'n thiic - Nam ducfc khai niem dong di6n xoay chi^u va di6n ap xoay chi^u Biet each xac dinh ,d6 l6ch pha gii5a dien ap va circfng dong didn xoay chieu theo bi^u thiic hoac theo thi bi^u di6n chiing - Nam duoc cac dac didm cua doan mach xoay chieu chi co di£n trd thu^n ~ Nam duoc cac gia tri hi6u dung va each tinh cong suat toa nhi6t trung binh cua dong di6n xoay chi^u Ve ki n i n g - Ren luyen ki nang quan sat GV tid'n hanh thi nghiem co sit dung dao d6ng ki dien tif, tit riit cac k6't luan cua bai hoc II-CHUXNBI Gido vien - Chu^n bi mo hinh may phat dien xoay chi6u va dien k6' - Dao d6ng ki dien tir, ngudn dien xoay chi^u hoc sinh, may phat am tan Hpc sinh - On lai cac kiah thiic ve dinh luat Om va hien tucmg cam ling di6n ttr da hoc ldp 11 THPT Ill - THI^T K f H O A T D N G DAY H O C Hoat d6ng cua hoc sinh Hoat ddng Kiem tra, chu^n b| dieu kien xuat phat HS suy nghl ca nhan tim cau tra Icri - Khi tiir thong qua mat gicfi han boi mach dien km bien doi theo thcfi gian Trd giup cua giao vi#n GV neu cau hoi kidm tra kien thiic cu - Hi6n tuong cam utig di6n tix xay nao ? - Khi do, goc a bi6'n thi6n theo th6i gian, suy ttr th6ng qua mat gi6i han bcri khung day kin bia'n thien theo thcfi gian Vi vay day xua't hi6n m6t suat difen dong cam ling - Khi cho khung day quay deu tit trucmg vdi t6'c goc co nhu hmh ve sau day, khung co sua't hi6n sua't di6n dong cam ling khong ? Tai ? - Quan sat tha'y kim cua dien ke dao dong sang phai roi sang trai m6t each tu^n hoan Chiing to su^t dien d6ng khung day bi^n thi6n tudn hoan - Yeu c^u HS quan sat GV tien hanh thi nghi6m v6i mo hinh may phat dien xoay chieu co noi v6i dien ke G, sau dua nhan xet ve gia trj cua suat dien d6ng cua may phat dien xoay chieu ? GV thong bao - Sua't diSn dong xua't hien khung day bie'n doi theo thcfi gian theo dinh luat dang sin, thucmg goi tat la sua't di6n d6ng xoay chieu : e = EQ cos(cot + (po) HS tiep thu, ghi nhd - Chu ki va tSn s6' cua bien doi cua suat di6n dong lien he vdfi tan so goc co bdi , „ 271 „ CO cac cong thuc: = — , i = CO 2n - Sua't dien d6ng tao bdi may phat dien xoay chieu cung co bidu thiic dang nhu tren Hoat dong Tim hieu dien ap xoay chieu va dong dien xoay chieu - Khi do, mach co dao d6ng dien cudng biic vdi t^n sd ciia suat dien d6ng may phat di6n xoay chieu tao Giua hai dSu d o ^ mach cd m6t dien ap bi6'n thi6n theo thdi gian theo dinh luat dang sin HS quan sat GV tia'n hanh thi nghiem vdi dao dong ki dien tu - Do thi cua didn ap tren hai d^u mach dien cd dang hinh sin GV neu cau hoi dd HS tim hidu dien ap xoay chieu - Neu ndi hai cue cua may phdt dien xoay chidu vdi mot doan mach ti6u thu di6n thi dien ap giiia hai ddu doan mach cd bidu thiic nhu tha' nao ? GV neu cac cau hoi goi y - Nhan xet gi vd dao dOng dian mach tiau thu ? - Lam thi nghifm nghiem nhu th6' nao dd kidm tra ? GV tien hanh thi nghiem va yfeu eiu HS quan sat dd nit nhan xet GV thdng bao - Trong trudng hop t6ng quat, bidu thiic cLia dien ap gifia hai dau doan mach xoay chidu AB va cudng dd dong dian qua nd cd dang : u = UoCos(cot + (p]) i = lQCos(cot + (p2) - Dai luong cp = cpj -cpj goi la lach pha cua u so vdi i Na'u cp > thi u sdni pha so vdi i Neu (p < thi u trd pha so vdi i Na'u [...]... nhiet lupng toa ra tran dian trd thudn d hai trudng hpp la nhu nhau ? 9 A I = Io B I = V2lo C I = i D 1 = ^ 2 V2 Cau 6 Cho cudng dp ddng lian xoay chidu chay qua mdt doan mach la i = 2sinl00t (A) Cudig do ddng dian hiau dung nhan gia tri nao trong cac gia tri sau day ? A I = 2A B I = IA C I = 4A 10 D 1= V2A BAI27 MACH DifiN XOAY CHI^U CHI CO TU DifiN, CUdN CAM I-MUCTlfiU 1 Vi ki^'n thiic - Hidu dupe... 0 vi tu dipn khdng cho ddng didn chay qua CAu 2 Dat vao hai ban cua tu dipn mdt dien ap xoay chidu u^Upsincot, cudng dp ddng dien chay qua tu dien la A i = CUQCOs(cot) ' , n B i = coCUoCos cot+— V 2 C i = coCUosin(cot) D i^coCUpsin cot + — CAu 3 Tang tdn sd gde eua dien ap dat vao tu dien ga'p 2 ldn thi dung khang cua tu dien se A tang ga'p 2 ldn B giam 2 Idn C tang gap 4 ldn D khdng thay ddi CAu 4... B N Tdng trd cua doan mach la: A Z = J R ^ + coL- 1 1 OOC] Ci)C2 B Z = j R ^ + C Z = R^ + D Z = R'^ + c o L — ^ coC\) Cau 5 Cho doan mach nhu hinh ve L •^000000^ B Tdng trd eua doan mach la A Z = coLi +C0L2 B Z = coL] -a>L2 C Z = L , + L o D Z = + coL] o)L2 CAu 6 Cudng dp ddng dien ludn luOn trd pha hon dien ap d hai ddu doan mach khi 29 A doan mach chi ed cupn cam C B doan mach cd R va C mdc ndi... dien ap xoay chidu cd gia trj hieu dung la lOOV thi dien ap hipu dung gifla hai ddu phdn tfl 1 la 100N/2V, giua hai dau phdn tfl 2 la 20 0V Hai phdn tfl 1 va 2 tucmg flng la A tu dien va cupn day khdng thudn cam B tu dien va cupn day thudn cam C dien trd thudn va tu dien D dien trd thudn va cupn day 30 BAI29 C 6 N G SUXT CUA DONG DifiN XOAY CHlfiu Hfi sd C6NG SUXT I-MUCTl£U LVe'ki^n thflc - Nam dupe dac... cdng CH2 ciia dao ddng ki dd nghian ciiu cudng dp ddng dien trong mach GV tia'n hanh lap rap va gidi thieu thi nghiem ma HS viia thiet ka' - Thi nghiam cdn cd: R = 5,lkQ, cupn day L : 3000 vdng (ed loi sdl) HS quan sat GV tie'n hanh thi nghiam va nit ra ka't luan - Quan sat tran man hinh dao dpng ki dien tii ta thdy ka't luan tim dupe bang con dudng li thuyet d tran la hoan toan diing TKBGVL # 12/ 2( NC)... cos (cot) Cau 4 Cho dong dian xoay chidu i = locoscot chay qua dien trd thudn R Biau thiic nao biau didn cdng sua't toa nhiat tiic thdi tran dien trd R sau day sai ? A p = Ri -2 Ri; C p = —^cos2cot 2 5 p = Rlocos^cot RIn RI§ „ , -cos2a)t cau 5 Cho cudng dp ddng dian xoay c;pieu i = Iosino)t chay qua difn trd thudn trong thdi gian t Na'u chb cudng dp ddng dien khdng doi I chay qua dian trd thudn dd trong... R, L, C mac ndi tiep Hoat ddng 2 Nghien ciiu doan mach R, L, C mac ndi tiep HS chu y Idng nghe GV gidi thieu doan mach R, L, C mdc ndi tia'p - Doan mach gdm mpt dian trd thudn R, mpt cupn cam thudn cd dp tu cam L va •mpt dien dung C mac ndi tia'p Ta gpi doan mach dd la mach RLC ndi tia'p R ^A L L 1—•—' M 75?R5OTr^—•-A N 1 c B# GV nau eau hdi ve vdn dd cdn nghian cflu 22 - Dat vao hai ddu A, B cua doan... hai ban tu ? - Dian tich tran ban M d thdi didm tia: C 1 1 M N q = Cu = CUQ sin cot - Cudng dp ddng dien: i = —i = CcoUn cos cot " dt => i = IQ cos (Ot, vdi IQ = CCOUQ 12 A B 'V Mat khae, ta ed u = UQ sin cot => u = Un '0 cos tot — 2 vay dien ap gifla hai ban tu dian trd pha hem so vdi cudng dp ddng dien trong mach m5t gde — HS thao luan ehung toan ldp - Cdn mpt mach dian chi ed tu dian Dian ap dat... trong 3 linh kian didn trd thudn R, tu dien C, cupn cam L thudn cam hoac gdm 2 trong 3 linh kian tren mdc ndi tiep Bang thuc nghiem tha'y rang cudng dp ddng dien trong mach ciing pha vdi diari ap dat vao hai ddu mach dian Mach dian dMqc cdu tao bdi 20 A R mdc ndi tia'p vdi C B L mac ndi tia'p vdi C C chi cd L D chi cd R BAI28 MACH CO R, L, C M A C N 6 I TifiP CdNG HUONG DifiN I-MUCTl£u 1 \ i kid'n... tra ldi cAu hdi dd Hoat ddng 2 Tim hieu cdng suat tiic thdi va cong suA't trung binh GV nau eau hdi dd HS tim hidu edng sudt tfle thdi - Cdng sudt tfle thdi la cdng sudt tiau HS thao luan ehung toan ldp thu dian eua mach dipn d mdi thdi didm Ta ed p = ui va dupe xac dinh bang p = ui Nd^u mpt = Uoloeoscot.eos(cot + cp) => p = UI2.eoscot.cos(cot + cp) - UI cos cp + UI cos (2cot + cp) doan mach cd ddng