Today's lab also focused on the steady-state response of electrical circuits to sinusoidal inputs. In this lab, we were able to finally calculate and demonstrate that while input and output signals have the same frequency, they have different amplitudes and phase angles.
In this lab, we will measure the gain and phase responses of an inverting voltage amplifier circuit and compare these measurements with expectations based on concept and based on analysis.
Our main concentration in this lab was on the input-output relation governing an inverting voltage amplifier. This relationship is the following,
given the inverting circuit below:
Our pre-lab required that we derive the relationship between Vout and Vin. We did so below using nodal analysis at +Vin, the negative input terminal of the op amp, and at +Vout.
Below are our calculations of the gain and phase shift of the circuit outputs at varying frequencies.
Circuit construction is pictured below containing two 10 kOhm resistors, a 0.1uF capacitor, and the traditional OP 27 op amp we've continually used throughout the semester.
Next we applied input voltages at three different frequencies:
100 Hz, 1 kHz, and 5 kHz respectively.
Below are the images from the oscilloscope window.
From the data obtained through our oscilloscope's readings, we found the measured values which are listed below. Our readings were ideal for real-world predicaments.
Below are the calculation errors.
Clearly there was an error in our interpretation of our data for our gain values. The phase shift calculations were nearly ideal, yet we had such discrepancies in our gain. I believe this is a direct result of poor data collecting.
This lab has so far been the most practical in terms of showing us theory measured in the real world. Steady-state responses have been significantly clarified.
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