title: Op Amps: Design, Application, and Troubleshooting
author: David Terrell
description: One of the book's greatest strengths is the easy-to-read conversational writing style. The author speaks directly to the student in a manner that encourages learning. This book explains the technical details of operational amplifier circuits in clear and understandable language without sacrificing technical depth.
zlib_text: 5
  The Operational Ampliﬁer
  Assessment Problems
  AP 5.1 [a] This is an inverting ampliﬁer, so
  vo = (−Rf/Ri)vs = (−80/16)vs,
  so
  vo = −5vs
  vs( V)
  0.4
  2.0
  3.5
  −0.6
  −1.6
  −2.4
  vo( V)
  −2.0
  −10.0
  −15.0
  3.0
  8.0
  10.0
  Two of the vs values, 3.5 V and −2.4 V, cause the op amp to saturate.
  [b] Use the negative power supply value to determine the largest input voltage:
  −15 = −5vs,
  vs = 3 V
  Use the positive power supply value to determine the smallest input voltage:
  10 = −5vs,
  vs = −2 V
  Therefore
  − 2 ≤ vs ≤ 3 V
  AP 5.2 From Assessment Problem 5.1
  vo = (−Rf/Ri)vs = (−Rx/16,000)vs
  = (−Rx/16,000)(−0.640) = 0.64Rx/16,000 = 4×10−5Rx
  Use the negative power supply value to determine one limit on the value of Rx:
  4×10−5Rx = −15
  so
  Rx = −15/4×10−5 = −375 kΩ
  Since we cannot have negative resistor values, the lower limit for Rx is 0. Now use
  the positive power supply value to determine the upper limit on the value of Rx:
  4×10−5Rx = 10
  so
  Rx = 10/4×10−5 = 250 kΩ
  Therefore,
  0 ≤ Rx ≤ 250 kΩ
  5–1
  
  5–2
  CHAPTER 5. The Op