Question

Electronic Devices help!

Problem #5. (40 points) What is the value of Vout assuming the op-amp is ideal? R4 V1=270 V2=470- V3=8V Vmax - #- 12V Problem #6. (40 points) Given an input sinusoidal signal with an rms value of 20 mV, design an operational amplifier circuit to give an output voltage of 1 Vrms. The phase of the output signal is not important.

Answer 1

I RA pun 15k. • Given: Ri I V=2r-un V=4V - um R2 I2 V3 = 6V - MMR I A V3 = 6V 15K Iz Vmax = 1 12 V We have to find o assuming the ob-amp is ideal. Since under - Ideal opamp. virtual gobund concept is applied So. Vd=0 t-v=0 V = vt = 0 Apply kcl at node o or=vt=0 Ist I2 + I3 = I =% + + 4 = → 12 + 20 + 24 = -6 Since Here We get Vo=-14v. but maximum ocetpeet of opamp max = £12V. We coill never get a ouffet greater than Virzax If out bcet getting gee etter) he outside range of Vomax by theoritical calculation then it will ) convert to Vmax= & 12v. I . Vo = - 148 1 So, loutput of opamp = Vout = -12V

• Giveni R2 20 mm 20 Sinusoidal Input signal yms, Vin = 20mV) Sinusoidal output Voltage Vout = 1 Vims Here we have design an opamp. for geffing vocet = |Voms Since The phase of ocet peet signal is not important We have to design Inverting opamp or Non-Juventing @ Design opamp with Non - Investing :- tef the opamp :- fere snpet Vout – Nome is applied to R - Non-Inverting = 1000 = 50 terminal Vout = 1Vrms Vin = 20 m Vomslo bamp is ideal. According to virtual ground concept ! - V+ -v- V+ - Vinar u VT Vin Appre kci at node or - V-Vout R1 R2 > -- Vou = - R2 V- VOCE = V-11+ R) =) Vocet = vin ( 1+ R) (*V* = Vin) > yote = (1+ → It Rai = 1000 = 50

(1 + R2) = so R2 = 49 R2 = 49R1] The value of Re and Ri, full fill the desired ouffeet Should Follow the condition R2 = 49 Ril In this way Non-In verting ferminal ispomp is designed to get the desired value of amplutet after afplying given inpat O Design Muerting obamp :- R Vout - - 1 Vrms un Ri 1000 = -50 20mvrms un Vout = -1 Vosms 20 Yn Vans aut- 20 Here Input is applied to Non-verting terminal. According to virtual ground concept :- Vtav NOTE: 2 [V - V+=0 Exact value of Riand Apply ko at node R2 annot bend because many values of Riand Re. are poser ble So, only Relation can be obtained According to relation R2 - Vocef = -(50) Obamb.can be design : vm L o. R2 = 50R for getting desired out but by using Investing opamb., R2 and Ri should follow condofron R2 = sori