Operational Amplifier Circuits Lab Report: Comparing Ideal and Actual Op-Amp Behavior - Pr, Lab Reports of Mechanical Engineering

Download Operational Amplifier Circuits Lab Report: Comparing Ideal and Actual Op-Amp Behavior - Pr and more Lab Reports Mechanical Engineering in PDF only on Docsity! This old lab report is ok, but yours can be better. Don’t copy it or paraphrase from it. V Req It V R1 V R2 + ..+ V Rn + EMCH 361 Operational Amplifier Circuits Lab An Old Student 23 September 2002 Introduction The purpose of this experiment is to compare the operation of an actual operation amplifier with the expected behavior of an ideal op-amp based on mathematical models. The mathematical analysis of the operational amplifier requires an understanding of Ohm’s Law and Kirchhoff’s Voltage and Current Laws. Ohm’s Law states that V=IR, where V is voltage, I is current, and R is resistance. Kirchhoff’s Current Law (KCL) states that the sum of the currents entering a node equals the sum of the currents leaving the node while his Voltage Law (KVL) states that the sum of the voltage drops around any closed loop equals the sum of the voltage rises around that loop. By applying KCL, the total current entering a parallel branch circuit such as the one formed by R1 and R2 in the provided circuit (R1||R2) must be equal to the current flowing through R1 plus the current through R2. An application of KVL proves that the voltage across the parallel resistors is equal. Using these two conditions and applying Ohm’s Law, the following expression for total current (It) is obtained: Eq. 1 This can be simplified, by dividing both sides by the voltage, to: Eq. 2 This can be symbolically represented for a system of n parallel resistors by: Eq. 3 Similarly, the equivalent resistance through a series circuit can be found by considering that the sum of the voltage drops across the two resistors must be equal to the sum of the voltage drop across an equivalent resistor. Since the current through both resistors is equal, the following equation for voltage can be developed: Eq. 4 By dividing the equation through by total current (It), the equation simplifies to: Eq. 5 Req 1 n i R1 1−∑ =       1− 1 Req 1 R1 1 R2 + ..+ 1 Rn + It Req⋅ Vt It R1⋅ It R2⋅+ ..+ It Rn⋅+ Req R1 R2+ ..+ Rn+