Question

1. Referring to Fig. 1: (12 pts. a. Determine the type of feedback circuit per stage b. The output voltage of the first stage. c. The current flowing through R4. d. The output impedance Zof of the last stage R2 1 KO Vec 15 V А в 15 V F 741C 74106 O G I 1 MA (1 VE -15 V 100 kg 512 Fig. 1 2. Design a 555 timer that free-runs at a frequency of 1 kHz and a duty cycle of 75 percent. Use a 1uF capacitor. Draw the circuit and the output waveform. ( 12 pts.] resistor is 3. In the op amp circuit of Fig. 2, find the value of Rso that the power absorbed by the 10-k 10 mW. Use Vs = 2 V. (12 pts.] 10 k2 Fig. 2

Answer 1

15 IMA Elke 04 - 15 look a ΒΙΚΑ 784 (a) Bith stage are the love feed back of R2 Ikon the stage one in to ve feed back (See the solution) 16 Olp of the Ist stage IMA 6 RIKE at the ove terminal vertual ground so that point B vo stage is also zero Cor some bas the tre terminal) The current in R is Zero, The I mA current will go through the Resistor R2 KUL VB - R2. IMA = V. V8-0 (vertual ground) on sx 18 x 1x103 = 16 VOE -I Volt op of Ist stage is at volt Current in Rq here by the concept of vertual grounded both terminal are in tomp Some voltage (or potential) annay Ru 51kn it Second stage Second at Ve= -1 Volt Ra looks Ve=VE - 1 Volt

Current in R4 = VE = Ru I - 19.69A 51 Ry Crrent is 19.6MA (dense (up word) for the Olp impedence ZOE = Ver firs we have to calculate I of v current will not go to G op.amb Er alvot NE 19.64 100kr KVL 51kn VE - look rx 19.6 MA = V WG= + - 100x 18 8 x 19.6x106 Va= - 2. 96 No 14 Voltage is not revere so that wive feed back (some bolanity) I = 19.6MA 2.96 ZOE = 296 151 ks

0 555imey or free Yoming on Y diagram watan 3 7 0 olup Given that 555 3tvo free running beq - 1 KHZ Duty cycle 75% CA IME We know the formula of free running Peq. and duty cycle Free woning heq fra Puteose = 1020 Duty cyde - Ce ntre and to Dividing Equation © by @ 1.45 75 1087.5 have any pro hovyoo tatro - 3 svaus x)bº 1981-5 Re-toorse Rat RB - 1087.5 ? Putting the P* Rig) value in Ean 2 185 Pp +2 R8 = 1027:52100 CRA + 10x2PB) 100 100 DatsA RA+ 2 RB = 1450 RA+ RB - 1087.5 r RA+ Q RB = 1450 m 1087 5X100 75 75

& (11) By solving Equation RA= 725 se RB = 362.52 Design barometer of a 555 timer is RA = 725r RB = 362.55 te - UF fya 1KHz Duty cycle = 75% Elokn Circuit 48 w ve feed back velt configuration & 4oks Enivers that we arolt toka I I By the concept of vertual grounded both terminal are in some potential + = v. con Vo R vo Given V = Vs= 2 Volt for coment I I & loka TV -2 Volt K = 2V0H also given loks absored lomw bower Ament I= Ř S RADO we know the formula of fouer - I- 2 PE VRT-TPR) - T. Put in Equation ④ We have to calculate vo Hage Voor toxicºs (esp) 10 Current I After calculing R. 53.24 kr Ra 53.24 kr I IS RHO