BAT BA TANGAS STATE STATE UNIVERSITY UNIVERS ITY COLLEGE OF ENGINEERING, ARCHITECTURE ARCHITECTURE AND FINE ARTS ELECTRONICS ENGINEERING DEPARTMENT
Experiment 2 Sii!"n#C"ntr"e$ Re!ti%er
S&'mitte$ '() Bri"ne*, Anne M+r+ret RC+ti", ."/n C+r" AM+&n$+(+", I+n De0in SECE 132
S&'mitte$ t") Dr- Gi B- B+rte In*tr&!t"r
Septem'er , 234
I.
OBJECTIVE: - Dem"n*tr+te + pr+!ti!+ $"5n" " met/"$* "6 te*tin +n SCR 7it/ "/mmeter2- S/"7 t/e t&rn#"n 8%re9 +n$ t&rn#": 8re*et9 met/"$* 6"r +n SCR;- Determine t/e ee!tri!+ !/+r+!teri*ti!* "6 + p+rti!&+r SCR1- De%ne t/e 0+ri"&* SCR p+r+meter*INTRODUCTION: T/e PN <&n!ti"n 6r"m +te t" !+t/"$e "6 +n SCR !+n 'e te*te$ 7it/ +n "/mmeter *imi+r t" + re&+r $i"$e- H"7e0er, te*tin 6r"m +n"$e t" +te 7i n"t in$i!+te i6 +n SCR i* 7"r=in pr"per(, 'e!+&*e "ne "6 t/e PN <&n!ti"n i* +7+(* re0er*e 'i+*e$- T/e SCR !+n 'e te*te$ +n "/mmeter '( p+!in t/e p"*iti0e e+$ "n t/e +n"$e +n$ t/e ne+ti0e e+$ "n t/e !+t/"$e 7it/ t/e +te e6t "pen T/e meter */"&$ re+$ /i/ "r in%nite re*i*t+n!e- P+!in + !ip e+$ 6r"m t/e +n"$e "r p"*iti0e e+$ "6 t/e "/mmeter t" t/e +te trier* t/e SCR +n$ t/e meter */"&$ in$i!+te "7 re*i*t+n!e>/en t/e !ip e+$ i* rem"0e$, t/e meter !"ntin&e* t" in$i!+te "7 re*i*t+n!e i6 t/e p"7er *"&r!e i* *&?!ient t" pr"$&!e t/e re@&ire$ /"$in !&rrent T" !"n$&!t, t/e SCR m&*t /+0e it* +n"$e m"re p"*iti0e t/+n it* !+t/"$e- >/en t/e +te 0"t+e i* m+$e m"re p"*iti0e t/+n it* !+t/"$e, t/e SCR t&rn* "n %re* +n$ !&rrent "7* 6r"m !+t/"$e t" +n"$e- >/en t/e +te 0"t+e i* ++in m+$e e@&+ t" "r m"re ne+ti0e t/+n t/e !+t/"$e, !&rrent !"ntin&e* t" "7 t/r"&/ t/e SCR- T/e SCR i* t&rne$ ": "r re*et '( re$&!in t/e !&rrent t/r"&/ it 'e"7 it* /"$in !&rrent-
II.
MATERIALS NEEDED: Fixe$ 2#V p"7er *&pp( St+n$+r$ "r $iit+ 0"tmeter 433 SCR = re*i*t"r +t 3-4 > 8R 9 3 = re*i*t"r +t 3-4 > 8R G9 22 = re*i*t"r +t 3-4 > 8R A9 2 SPDT *7it!/e* 8S +n$ S29 Bre+$'"+r$ 6"r !"n*tr&!tin !ir!&it PART I: TESTING AN SC AN OHMMETER - Set t/e "/mmeter t" t/e mi$r+ne *!+e2- C"nne!t t/e "/mmeter t" t/e SCR +* */"7n in %&re 1- +n$ re!"r$ t/e meter re+$in in t+'e 1-
PART II: OPERATION OF AN SCR - C"n*tr&!t t/e !ir!&it */"7n in %&re 1-22- Set *7it!/e* S +n$ S2 +* in$i!+te$ +n$ t/en +pp( p"7er t" t/e !ir!- In t/e %r*t r"7 "6 t/e $+t+ t+'e -; 8Sim&+ti"n9 +n$ -1 8A!t&+9, re!"r$ t/e 0+&e* "6 VG +n$ VA1- M"0e S t" p"*iti"n B +n$ re!"r$ t/e 0+&e* "6 VG +n$ VA in t/e *e!"n$ r"7 "6 t/e $+t+ t+'e4- M"0e S t" p"*iti"n A +n$ re!"r$ t/e 0+&e* "6 VG +n$ VA in t/e 6"&rt/ r"7 "6 t/e $+t+ t+'e- M"0e S2 t" p"*iti"n B +n$ re!"r$ t/e 0+&e* "6 VG +n$ VA in t/e 6"&rt/ r"7 "6 t/e $+t+ t+'e- M"0e S t" p"*iti"n A +n$ re!"r$ t/e 0+&e* "6 VG +n$ VA in t/e 6"&rt/ r"7 "6 t/e $+t+ t+'e-
III.
RESULTS
PART I: TESTING AN SCR WITH AN OHMMETER Table 1.1: Ohmmee! Rea"#$% &S#m'la#($) G+te 8G9
An"$e 8A9
C+t/"$e 89
N"ne P"*iti0e N"ne
P"*iti0e P"*iti0e Ne+ti0e
Ne+ti0e Ne+ti0e P"*iti0e
Re+$in 8 H "r L9 L H
Table 1.*: Ohmmee! Rea"#$% &A+'al) G+te 8G9
An"$e 8A9
C+t/"$e 89
N"ne P"*iti0e N"ne
P"*iti0e P"*iti0e Ne+ti0e
Ne+ti0e Ne+ti0e P"*iti0e
Re+$in 8 H "r L9 L H L
- An SCR 7i /+0e /i/ re*i*t+n!e 'e6"re 'ein triere$2- An SCR 7i /+0e "7 re*i*t+n!e 'e6"re +6ter triere$;- T/e +n"$e#t"#!+t/"$e re*i*t+n!e "6 +n SCR !+n 'e !/e!=e$ i=e + n"rm+ $i"$e1- An SCR i* 'ein te*te$ 7it/ +n "/mmeter- >/en t/e !ip e+$ "n t/e +te i* rem"0e$, t/e meter in$i!+te* /i/ re*i*t+n!e- T/i* $"e* n"t pr"0e t/+t t/e SCR i* $e6e!ti0e, '&t t/+t t/e p"7er *"&r!e "6 t/e meter i* n"t *&?!ient t" pr"$&!e t/e ne!e**+r( trierin !&rrent t/r"&/ t/e $e0i!e-
PART II. OPERATION OF AN SCR Table 1.,: &S#m'la#($ #$ M'l#-#m) S S2 VG C"n$iti"n C"n$iti"n A B A A A
VA
A A A B A
-2 mV 2;-1 mV -2 mV -2 mV -2 mV
- V 3-;1 mV - V 2 V 3-;4 mV
S2
VG
VA
C"n$iti"n "6 SCR 8"n "r ":9 On O: On On On
Table 1.: &A+'al) S
C"n$iti"n "6
C"n$iti"n
C"n$iti"n
A B A A A
A A A B A
2mV -;V 3-mV ;mV 2mV
-V -V -V -V -4V
SCR 8"n "r ":9 On O: On On On
- Be6"re %rin, t/e 0"t+e 6r"m +n"$e t" r"&n$ "6 t/e SCR i* e@&+ t" 3V2- >/en t/e +te i* m+$e m"re p"*iti0e t/e SCR %re* +n$ IA;- On!e t/e SCR %re*, t/e +te "*e* !"ntr" +n$ t/e !&rrent i* +"7e$ t" "7 t/r"&/ t/e SCR1- >/en t/e SCR i* !"n$&!tin, t/e 0"t+e 6r"m t/e +n"$e t" r"&n$ i* e@&+ t" V!!4- T/e SCR !+n 'e t&rne$ ": '( re$&!in t/e !&rrent t/r"&/ it 'e"7 it* /"$in !&rrent-
IV.
ANAL/SIS OF RESULTS: Sim&+ti"n in M&ti*im)
F#%. 1.1: S0#+h C($"##($ &S 1: A S*: A)
F#%. 1.*: S0#+h C($"##($ &S 1: B S*: A)
F#%. 1.,: S0#+h C($"##($ &S 1: A S*: A)
F#%. 1.: S0#+h C($"##($ &S 1: A S*: B)
F#%. 1.2: S0#+h C($"##($ &S 1: A S*: A)
T/e %&re +'"0e */"7* e0er( *7it!/in !"n$iti"n*- T/e "'t+ine$ 0+&e* 6r"m t/e experiment+ +n$ +!t&+ +re *"me7/+t !"*e- T/e( !+nn"t 'e ex+!t( t/e *+me 'e!+&*e t/ere +re itte intern+ re*i*t+n!e in t/e +!t&+ !"mp"nent* $&rin t/e impement+ti"n 7/i!/ i* !+&*e$ '( t/e m+n&6+!t&rer*-
V.3UESTIONS AND PROBLEMS: - T/e etter* SCR *t+n$ 6"r *ii!"n#!"ntr"e$ t/in* m&*t /+ppen t" !+&*e +n SCR re!ti%er- Exp+in t/e &*e "6 t/e 7"r$ re!ti%er in t/e n+meRe!ti%er* +re &*e$ in SCR in "r$er t" !"n0ert* +tern+tin !&rrent 8AC9, 7/i!/ peri"$i!+( re0er*e* $ire!ti"n, t" $ire!t !&rrent 8DC9, 7/i!/ "7* in "n( "ne $ire!ti"n2- >/+t t7" t/in* m&*t /+ppen t" !+&*e +n SCR t" %re V"t+e "n t/e +te m&*t ex!ee$ t/e t&rn#"n t/re*/"$ "6 t/e SCR- Se!"n$ i* t" m+int+in + minim&m /"$in !&rrent 6r"m +n"$e t" !+t/"$e- On!e t&rne$ "n, t/e SCR 7i rem+in *e6#+t!/e$ in t/e "n *t+te &nti t/e !&rrent t/r"&/ t/e +n"$e +n$ !+t/"$e 6+* 'e"7 t/e minim&m *e6#/"$in !&rrent;- >/+t i* t/e $i:eren!e 'et7een trierin +te !&rrent +n$ /"$in !&rrent Trierin +te !&rrent i* t/e 0+&e "6 +te !&rrent ne!e**+r( t" *7it!/ t/e SCR 6r"m t/e 6"r7+r$#'"!=in rei"n t" t/e 6"r7+r$# !"n$&!ti"n rei"n &n$er *pe!i%e$ !"n$iti"n 7/ie /"$in !&rrent i*
t/e 0+&e "6 t/e +n"$e !&rrent 'e"7 7/i!/ t/e SCR *7it!/e* 6r"m t/e 6"r7+r$#!"n$&!ti"n rei"n t" t/e 6"r7+r$#'"!=in rei"n1- H"7 m&!/ 0"t+e +!r"** t/e +n"$e#!+t/"$e termin+* "6 + me$i&m# p"7er SCR +6ter it /+* %re$ A6ter %rin t/e SCR, t/e V"t+e 6r"m +n"$e t" !+t/"$e 7i 'e e@&+ t" V!!4- H"7 !+n +n SCR 'e m+$e t" !"n$&!t T/e +te m&*t 'e triere$ +n$ it !+n 'e +*" 'e t&rne$ "n '( *ini%!+nt( r+i*in t/e temper+t&re "6 t/e $e0i!e "r r+i*in t/e +n"$e#!+t/"$e 0"t+e t" t/e 're+= "0er 0+&e- H"7 !+n +n SCR 'e t&rne$ ": T/ere +re t7" ener+ met/"$* 6"r t&rnin ": +n SCR- Fir*t i* '( +n"$e !&rrent interr&pti"n +n$ *e!"n$ i* t/e 6"r!e$#!"mm&t+ti"n te!/ni@&e- F"r!e$ !"mm&t+ti"n i* t/e 6"r!in "6 !&rrent t/"&/ t/e SCR in t/e $ire!ti"n "pp"*ite t" 6"r7+r$ !"n$&!ti"n-
