3.6
Consider a car with cruise control using an op amp circuit to maintain a constant speed. This circuit employs the function of an op amp as an integrator and differentiator.
An ideal integrator and differentiator can be created from an inverting operational amplifier circuit by replacing the feedback and input resistors with capacitors, respectively.
An integrator is an op amp circuit that generates an output in proportion to the integral of the input signal.
Conversely, a differentiator produces an output proportional to the rate of change of the input signal.
By applying Kirchhoff's current law at the inverting node of both circuits and utilizing the current-voltage expressions for the resistor and capacitor, an equation relating the output and input voltages can be derived.
Upon integrating the equation for the integrator circuit on both sides and assuming the capacitor discharges before signal application, the final expression demonstrates that the output voltage is proportional to the input's integral.
In contrast, for the differentiator circuit, the output voltage is proportional to the derivative of the input signal.
Op-amp circuits have significant applications in various fields, including automotive engineering. One such application is cruise control systems in c…
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