Download UC Berkeley EE 40/42/100 Midterm 2, Spring 2007 and more Exams Microelectronic Circuits in PDF only on Docsity! UC BERKELEY EE 40/42/100, Spring 2007 Page 1 of 9 EE 40/42/100, Spring 2007 Prof. Chang-Hasnain Midterm #2 April 11, 2007 Total Time Allotted: 80 minutes Total Points: 100 1. This is a closed book exam. However, you are allowed to bring two page (8.5” x 11”), single-sided notes. 2. No electronic devices, i.e. calculators, cell phones, computers, etc. 3. SHOW all the steps on the exam. 4. Remember to put down units. Points will be taken off for answers without units. Last (Family) Name:_____________________________________________________ First Name: ____________________________________________________________ Student ID: ___________________________ Signature: ________________________ Circle the class you are in: EE 40 EE 42 EE 100 Circle one discussion session you are in Monday Tuesday Wednesday Thursday Friday Dis TA Dis TA Dis TA Dis TA Dis TA 10:00 100(42)- 101 Richard 40- 105 Mike 100- 107 Haibo 11:00 40-101 Mike 100-105 Haibo 100(42)- 102 Tanya 13:00 40-102 Jia 40-103 Isaac 100-104 Tanya 15:00 100-106 Haibo Problem 1 (22 pts) Problem 2 (10 pts): Problem 3 (15 pts) Problem 4 (18 pts) Problem 5 (35 pts): Total UC BERKELEY EE 40/42/100, Spring 2007 Page 2 of 9 1. (22 pts) Assume the diode in the circuit below using the simple piecewise model with a threshold voltage of 0.6V (also known as the large signal model in the text book). 1k_ + V1 - 1k_ 2V1Vin + Vo - (i) (4 pts) Re-draw the circuit assuming the diode is off. Express Vo as a function of Vin. 1k_ + V1 - 1k_ 2V1Vin + Vo - Figure 1 pt Vin = V1+2V1 (1pts) V1=Vin/3 (1pts) V0=2V1=2Vin/3 (1pts) (ii) (4 pts) Re-draw the circuit assuming the diode is on. Express Vo as a function of Vin. 1kO + V1 - 1kO 2V1Vin + Vo - 0.6V Figure 1 pt V0=-0.6 V (3 pts) (iii) (4 pts) For what values of Vin will the diode be on? 2Vin/3 ≤ -0.6V (2pts) UC BERKELEY EE 40/42/100, Spring 2007 Page 5 of 9 3. (15 pts)Op-amp circuit: For the figure below: ia 3.3V 32k_ A B 4.7k_ 20k_ 3.3k_ + VX -io Assume both are ideal op-amps: 1. Find ia. ia= 3.3V/3.3K=1mA 2. Find io. io = -(3.3v+4.7K*1mA)/32K - ia= -1.25mA 3. Find Vx. Vx= -0.25mA*20K=-5 V UC BERKELEY EE 40/42/100, Spring 2007 Page 6 of 9 4. (18 pts) Consider the following circuit: Find the transfer function Vo/Vin(ω) There are many different ways to solve this problem. I think voltage divider and KCL are the simplest. Voltage divider method: CRj R LjR LRj CRj R Cj RLjR Cj R Vin Vo 2 2 1 1 2 2 21 2 1 1 1 //)//( 1 // !! ! ! ! ! ! + + + + "= + "= You DON’T have to simplify that to get full credit. However, in case you do simplify it, you should be able to get something similar to the following: )( )(*)1(* )(* )(*)1( )(*)1(* 1 2121 2 21 221 1221 12 12 1221 2 2 RRLjCLRRRR LRjRR LjRRCRjLRj LjRR LjRCRj LjRRCRjLRj CRj R Vin Vo ++! + != +++ + != ++ +++ + != "" " """ " "" """ " KCL @ ground method: UC BERKELEY EE 40/42/100, Spring 2007 Page 7 of 9 Cj RLjR LjR Vin Vo CVoj R Vo Lj VinVo R VinVo VinVoVwhereCVoj R Vo Lj V R V ! ! ! ! ! ! ! +++ + "= =++ + + + +==+++ 21 1 21 1 2 1 1 1 111 11 0 0 It can be further simplified to the result in voltage divider.
