Lab Day 25

During this day, we went over bode plots, which are plots in magnitude (decibels) and phase (degrees) of a transfer function versus frequency. The standard form of the Bode Plot contain many components: a gain K, a pole, a simple pole, and a quadratic pole. 

Here is a summary of rules when plotting Bode Plots:



This was the final blog entry for the class!!!

Lab Day 24

Signals With Multiple Frequency Components Lab 

In this lab we calculated the magnitude response of an electrical circuit and use this information to infer the effect of the circuit on some relatively complex input signals. We applied the following input signals types:

- a signal composed of multiple sinusoidal waves of different frequencies

- a sinusoidal signal with a time-varying frequency (aka sinusoidal sweep)

Here are the calculations for the pre-lab:

 This is a picture of our circuit:

Input voltage is a custom waveform: 20{sin(1000*pi*t)+sin(2000*pi*t)+sin(20000*pi*t)}:

 Here is the Vout across the resistor (blue) in comparison to the Vin (pink):

This is the calculation Theoretical vs Experimental with the %error.

In conclusion, we went over the transfer function, learned how to calculate gain and poles, and did a lab to see how input frequency affects the output graph.

Lab Day 23

Apparent and Power Factor Lab

The purpose of this lab was to use apparent power and power factor to quantify the AC power delivered to a load and the power dissipated by the process of transmitting this power. For the pre-lab we calculated the theoretical values of the circuit: Current, Voltage, Average Power, Apparent Power, and Power Factor.

For this circuit we will change RT values. All of the circuits will have the same input of 1V at 5Khz.

Here is the output of circuit at RT=47 Ohm.

For second part of lab we insert a 10 microF capacitor in parallel with Inductor and RL. Here is the output of circuit with input of 1V at 5Khz,

According to our experiment, higher RT value results in higher percent difference with theoretical value. However, with capacitor inserted into the circuit, the percent difference is lowered drastically. 

Lab Day 22

On this day we reviewed inductor and its parameters, went over average and maximum power calculation within AC circuits, and saw a demonstration to see how RMS values dictate maximum power of AC circuits. We did not have a lab for this day.

Lab Day 21

Inverting Voltage Amplifier Lab

In this lab assignment, we concerned with the steady-state response of electrical circuits to sinusoidal inputs. The input and output signals both have the same frequency, but the two signals can have different amplitudes and phase angles. We then measured the gain and phase responses of an inverting voltage amplifier circuit and compare these measurements with expectations bases on analysis. 

This is the pre-lab with the picture of the circuit. On the top right corner, we calculated the cutoff frequency of the circuit, the amplitude gain, and phase difference.

Picture of the 100Hz.

Picture of the 1KHz.

Picture of the 5KHz.

The chart of the bottom half shows the measurements to calculate the amplitude gain, phase difference, and it is compared with the results from the pre-lab with the %error.

OP Amp Relaxation Oscillator Lab

A "relaxation oscillator" is constructed by using some type of device that will act as a switch when a certain voltage is applied to one of its terminals. The "switching voltage" is usually the voltage across a capacitor that is being charged or discharged accordingly. 

We determined the value of R using the formula for the period T.

This is the picture of the circuit.

This is a picture showing the voltages for the OP Amp relaxation oscillator.

Lab Day 20

Phasors: Passive RL Circuit Response Lab

In this lab assignment, we measured the gain and phase responses of a passive RL circuit and compared these measurements with expectations based on analysis.

This is the pre-lab, where we showed that the amplitude gain and phase difference between the input voltage and input current are shown. Also the cutoff frequency for the circuit. 

This is a picture of our circuit.

We used the function generator to apply a sinusoidal input at Vin. The oscilloscope displayed both Vin and Vl.

We calculated the measured gains and phase differences between Iin and Vin for the three frequencies.

With the measurements we used to estimate the gain and phase difference between Vin and Iin and the gain and phase difference between Vl and Iin.

These results were compared with the value from the pre-lab, We do not have the ability to directly measure a time-varying current, so we used Iin=(Vin-Vl) / R

Lab Day 19

Impedance Lab

The purpose of this lab was to measured the impedance of three separate circuits and compare it with our calculated values. 

The output current from the 47 Ohm resistor and output voltage 100 Ohm resistor was measured.

This picture is showing the output at 10KHz.

The output current from the 47 Ohm resistor and output voltage from the microH was measured. 

This picture is showing the output at 10KHz.

 The output current from the 47 Ohm resistor and output voltage from the 0.1 microF was measured.

This picture is showing the output at 10KHz.

Here are the results from the three circuits, including their voltage and current measurements.

Conclusion: Today we went over impedance and admittance, and how to solve for them within circuits involving resistors, inductors, and capacitors.