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Mobile Studio Activity #4
Adam Steinberger
Page 1
IntroductionOperational Amplifiers (Op Amps) are a particular
type of linear electronic device that
amplify input signals through the use of negative feedback
loops. When Op Amps are
connected to capacitors in negative feedback loops, the input
signals can either be integrated
or differentiated. This is a direct result of the definitions of
current through a capacitor
= and voltage across a capacitor = 0 +1
0, which hold true
for Kirchhoffs Laws of Current and Voltage. In this lab,
Inverting Integrators and Inverting
Differentiators are used to manipulate triangle wave
signals.
Procedure
The protoboard at right was designed for this lab.
The output from the first Op Amp in the IC chip connects to
a 100k resistor in parallel with a 0.01F capacitor, which
connects to the negative input forming a negative feedback
loop. Connecting the negative input to a 10k resistor and
then to the source voltage causes the Op Amp to act as an
Inverting Integrator. For the other Op Amp circuit, the
negative feedback loop only contains a 1k resistor. However, the
negative input is connected
to a 0.01F capacitor and then to the voltage source. This
produces an Inverting Differentiator.
By connecting both negative inputs to the wave function
generator via Mobile Studio Desktop,
it is possible to produce a source voltage in the form of a
triangle wave of 1Vp-p at 2kHz.
Analysis
Readings were taken from Mobile Studio Desktop of the integrated
and differentiated
signals over a period of 500s. A screenshot of the resulting
graph (see page 3) was taken,
indicating peak to peak values for both time and voltage for
both output signals. A simulation of
the circuit was then designed using PSPICE, and a graph ( see
page 4) of the simulated output
8/9/2019 Mobile Studio Activity 4 Report
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Mobile Studio Activity #4
Adam Steinberger
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signals was created to verify the results from the Mobile Studio
readings. The two sets of data
are identical. A simplified expression for the source voltage
was used to simplify analysis,
assuming that it is understood that the frequencies of all
signals are identical and that the
values change signs every half a period. Integrating and
differentiating the source voltage
4000 produces output signals of 2 1 072 and 40 respectively.
Inspection of the datasuggests that these output signals are
correct because the integral of a sloped line is a quadratic
and the derivative of a sloped line is a horizontal line. Both
equations for output signals are
identical to the experimental data from the procedure and the
data from simulation. Slight
differences between all three sets of data are due to small
imperfections in the materials used,
static electricity in the air, power consumption by the
electrical components in the circuit, and
analytical simplification.
Conclusion
Using capacitors in Op Amp circuits can produce circuits that
will integrate and/or
differentiate signals.
