EET 331 Homework #4 page 1 of 3 ELECTRICAL ENGINEERING TECHNOLOGY PROGRAM EET 331 – ELECTRONIC DESIGN HOMEWORK ASSIGNMENT #4: CHAPTER 5 1. Solve problem 7 from Chapter 5 textbook. 2. Solve problem 13 from Chapter 5 textbook. 3. Solve problem 26 From Chapter 5 textbook. 4. Solve problem 28 from Chapter 5 textbook. Solve the following problems taken from exams of past years: PROBLEM. The circuit shown in the figure is used to measure the offset voltage for an operational amplifier (Device Under Test or DUT). The circuit is based on assuming that the second operational amplifier has an offset voltage that can be considered zero, and therefore only the offset of the DUT will play a role in the circuit. We will also assume that the biasing currents can be neglected. If the voltage at the output of the circuit is equal to 3V, calculate the input offset voltage for the Op Amp labeled as DUT. (Hint.- Offset is a DC signal). DUTIdeal_Op_Amp10Ω10kΩ1kΩ10kΩ10nFVout = 3.0 VEET 331 Homework #4 page 2 of 3 PROBLEM Consider the I-V converter of the figure a) Find the mathematical expression for the output voltage as a function of the input bias and offset currents (Ib and Ios) and the input offset voltage (Vos) b) Redesign the circuit to minimize the effects of the input offset and bias currents as much as possible c) Using your new design, calculate the output voltage with the following values: R = 1MΩ, Ios=1nA and Vos=1mV PROBLEM For the circuit in the figure below, find the expression for the output voltage as a function of the two biasing currents (IB+ and IB- ) and the offset voltage. (Disable the independent source and once again, apply superposition) 123R-+3k 12k36k Vo1k 2k2kEET 331 Homework #4 page 3 of 3 PROBLEM Using the following parameters for the two operational amplifiers shown in the circuit, calculate the voltages at the nodes labeled A through F. Write down your answers in the table below Hint 1.- Replace each Op Amp with its model. Hint 2.- The easiest way to approach this problem is by starting at node D. PROBLEM a) Given the circuit of the figure below, with R = 100 kΩ and IB = 100 nA, calculate the value of the output voltage due to the biasing current. U1 U2 Vio 5 mV 10 µV I+B -300 nA -80 pA I-B -200 nA -70 pA ANSWERS VA VB VC VD VE VF U1U2R11kΩR2100kΩR3100kΩR41kΩR5100kΩR6100kΩ- 500 mV +ABCDEF123R