Question

C3. An automatic streetlight pole with a sunlight detecting circuit is installed as shown in Fig.C3(a). The characteristic of the sunlight sensing device is illustrated in Fig. C3(b). The control circuit in Fig. C3(c) was well tested. A LED lamp Fig. C3(a) A light sensor for detecting the sunlight +10V Fig. C3(0) The characteristic of the light sensor * 2ΚΩ 2012 20kΩ 300k Fig. C3(b) Resistance EW 741 Op-amp 1000 20kΩ Kun Night-time Day-time Light Intensity (Lux) Control Circuit for LED lamp on/off (a) Explain the operations of the control circuit with aid of Fig. C3(b) (4 marks) and Fig. C3(c).

Answer 1

0 Solution : Given that Ilov > Zookel 20KR LE Readborce 100_2 optimp righl time gay-time Light interanyway fow C(C) cos @ wooting of control cioccit :- * The 741 Op Amp vönd here wooked as a comparabo. 2 via von incoling terminate 13 connected to bv Supply Vollazgo divietos seselances of dk and sakince of light OCnzo. Ziveoling teenival is connected to supply via two Equal ocbiglance of 20k) hence volage of investing terminal (V) will be v=10* ( 30% 2001 BK 19 One 8V uok

@ v voltage : 5 volls ow and OFF. LED. depending The given circuit is a light sensing crocuit which turns upon the poasence of light- F1J XD) is the resistance cu ve BCR used in the circuit. In presence of light (ory light) Ho scooberce deoscoso to 1000 100 -10* Thus. Vt voltage becomes - 100+2k Ų 1000 1024 IY :0.435V = 5vo gince V <V. duting daytime, output of comparatoo col be negative, Do MOOFET Bwitch will be off co dening daytime. tge LED semain offo Duding night Here, we have constance of sensoo jook.2. V7-10* 300 300k+Qh va 302K '= 10*300K 3000K JOQK = 9.93V vt -9093V = 10V. time so, during night JO MOOFET Switch will be 20. alkaong aussent fluo in cath of LED, V+ >V. oo cutput of op Amp will be +ve 5o, stooet light LED will gloud

I HOPE THIS ANSWER WILL BE HELPFUL TO YOU

PLEASE LIKE THIS ANSWER

THANK YOU.