American International University- Bangladesh
Department of Electrical and Electronic Engineering
EEE2210: Analog Electronics 1 Laboratory
Title: Study of Integrator and Differentiator.
Introduction:
By introducing electrical reactance into the feedback loops of op-amp amplifier circuits, we can cause the output to respond to changes in the input voltage over time. Drawing their names from their respective calculus functions, the integrator produces a voltage output proportional to the product of the input voltage and time; and the differentiator produces a voltage output proportional to the input voltage 's rate of change. The objective of this experiment is to get familiarized with integrator and differentiator circuits
Theory and Methodology:
Integrator: Op-amp Integrator is an operational amplifier circuit that performs the mathematical operation of Integration, that is we can cause the output to respond to changes in the input voltage over time as the op-amp integrator produces an output voltage which is proportional to the integral of the input voltage.
In other words the magnitude of the output signal is determined by the length of time a voltage is present at its input as the current through the feedback loop charges or discharges the capacitor as the required negative feedback occurs through the capacitor.
Fig. 1 (a): Op-Amp Integrator
Fig. 1 (b): Input-Output Characteristics
When a step voltage, Vin is firstly applied to the input of an integrating amplifier, the uncharged capacitor C has very little resistance and acts a bit like a short circuit allowing maximum current to flow via the input resistor, Rin as potential difference exists between the two plates. No current flows into the amplifiers input and point X is a virtual earth resulting in zero output. As the impedance of the capacitor at this point is very low, the gain ratio of Xc/Rin is also very small giving an overall voltage gain of
References: 1. Op-amp Integrator, Available: http://www.electronics-tutorials.ws/opamp/opamp_6.html 2. Op-amp Differentiator, Available: http://www.electronics-tutorials.ws/opamp/opamp_7.html. © Dept. of EEE, Faculty of Engineering, American International University-Bangladesh (AIUB) 4