Extra Credit on final exam

We went to the Pomona Fairplex 

We ask children want to build which kind animal robots want to build. There are bird, dog or bug.

Day 24

Transfer Function：

Use FreeMat to graph a transfer function. 

Codes

Graph

Signals with Multiple Frequency Components

In this lab, we calculate the magnitude response of an electrical circuit and use this information to refer the effect of the circuit on some relatively complex input signals. In particular, we will apply a signal composed of multiple sinusoidal waves of different frequencies and a sinusoidal signal with a time varying frequency ( a sinusoidal sweep).

When the frequency is low, the capacitor is open, the voltage cross R2 is half of Vin. When the frequency is high, the capacitor is short, the voltage cross R2 is 0.

Calculate the theoretical phase shift at different frequency.

Input graph. A custom waveform, 20(sin(1000πt)+sin(2000πt)+sin(20,000πt)) and sinusoidal sweep function, was created. 

Used Analog Discovery to measure Vin and Vout in the circuit.

Sweep wave.

When the wave at 500 Hz

.
When the wave at 1000 Hz.

When the wave at 10K Hz.

Output and the input voltage has some phase shift.


In second part of lab, the input voltage, sinusoidal sweep, has frequency 100Hz to 10Khz in 20ms.

The Vin and Vout rise and fall have same rate, but they are not phase shif.

Day 23

This lab assignment emphasizes the use of apparent power and power factor to quantity the AC power delivered to a load and power dissipated by the process of transmitting this power. 

In this lab, we are going to provide average power to load power when the power is delivery processing.

 We used a 10 ohm resistor, and use it to series with a 1mH inductor and three different resistor (10 ohm, 47 ohm, or 100 ohm) at three different times. and the resistor to be the load. 

When a sinusoidal wave with (1cos(2pi*5000t) in the circuit, and we calculate the power dissipated by the resistor. 

The is set up 

The resistors:  10ohm        47ohm           100ohm     

                      11.9ohm     48.6ohm        99.8ohm

The results and calculations.

When we used different resistor, we measured the voltage of the load and the voltage across the resistor in series.

The oscilloscope screen with 11.9 ohm resistor

The oscilloscope screen with 48.6 ohm resistor

The oscilloscope screen with 99.8 ohm resistor

When the phase difference are very big, we measured the value.

 

When the capacitor and resistor are in parallel, the voltages is measured.

The oscilloscope screen with 11.9 ohm resistor with a capacitor

The oscilloscope screen with 48.6 ohm resistor with a capacitor

The oscilloscope screen with 99.8 ohm resistor with a capacitor

The phase angles are very small nd less than 3 degrees for each.

Day 22

Professor Mason uses a demo to show us how AC power works. 

When professor Mason used AC power and DC power to light the bulb at the same voltage. We saw the AC one is dimmer. It showed that the bulb has less power with AC. 

When professor Mason increased voltage for AC above 1.4 times of the DC power, the bright went to the same high. 

Vrms = 1/sqrt(2) Vmax. 

When we read voltage Vmax, it instead of Vrms. So the power of AC is P=Vrms^2/R. 

summary
Today, we reviewed that the relationship between Vrms and Vmax, and proved how to calculate the power about AC.

Day 21

In this lab assignment, we will be concerned with the steady-state response of electrical to sinusoidal input. the input and output signals both have the same frequency, but the two signals can have different amplitudes and phase angles.

in the pre-lab, we going to derive formula, and use it.

the circuit is set up with 2 10KOhm, 1 1uF capacitor, and a op amp. 

Vin and Vout with frequency 100Hz

Vin and Vout with frequency 1KHz 

Vin and Vout with frequency 5KHz 

summary table,  

final table with gain and phase under the different frequency.

In this lab, build a oscillator on EveryCircuit.

during the building circuit, we are going to build a 99Hz. We calculate theoretical value for the pot, which is 8371Ohm.

the circuit is set up.

the picture is about Vout, the frequency is 99.8, its percent different is 1%.  

Day 20

In this lab assignment, we will be concerned with the stedy-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.

 

In the pre-lab, we have three dfferent frequency, Wc, Wc/10, and 10Wc, and Wc is 2.2*10^5 Hz.

We also find the cutoff frequency for the circuit:

                                 W:                  Wc                       Wc/10                   10Wc

                                              0.0321 /-45Ohm        0.0452/-5.711Ohm   4.52/-83.4 mOhm

A 22Ohm resistor and a 100uH inductor are used to set up circuit. 

f=35KHz, Vin=989.4mV, and I=31.25mA. we got 0.0316/-37.8 ohm.

 f=3.5k Ohm, Vin=973.4 mV, and I=38.55 mA. we got 0.0452/-6.3 Ohm.

  f=350k Ohm, Vin=994.8 mV, and I= 5.665 mA. we got 5.695/-78.12 mOhm.

Summary table. 

Day 19

Impedance

In this lab assignment, we measure impedes of resistors, capacitors, and inductors. The measured values will be compared with our expectations based on analyses. 

In the pre-lab, we calculate the impedance for RR, RL,and RC circuit.

The RR circuit is set up.

This picture is about the RR circuit with 1KHz. Vt= 1.354 V, I=13.2 mA. 

This picture is about the RR circuit with 5KHz. Vt= 1.354 V, I=13.2 mA.  

 This picture is about the RR circuit with 10KHz. Vt= 1.354 V, I=13.2 mA. 

The picture about resistor impedance = 47+ R, and the experiment value of resistors are 46.6Ohm and 99.9Ohm. so the experiment impedance is 146.5, its percent is 0.34%. 

The RC circuit is set up.

 This picture is about the RC circuit with 1KHz. Vt= 0.2652 V, I=40.05 mA.

  This picture is about the RC circuit with 5KHz. Vt= 1.0584 V, I=34.2 mA.

  This picture is about the RC circuit with 10KHz. Vt= 1.546 V, I=25.4 mA.

 A 2V sine wave  power is applied into a RL circuit.

 The RL circuit is set up

 This picture is about the RL circuit with 1KHz. Vt= 1.999 V, I=1.05 mA.

 This picture is about the RL circuit with 1KHz. Vt= 1.9774 V, I=4.955 mA.

  

This picture is about the RL circuit with 10KHz. Vt= 1.924 V, I=9.475 mA. 

When  different frequencies of 1kHz, 5kHz, and 10 kHz frequencies. In the capacitor circuit the current leads voltage by 90°

Summary:

Today, we learn that a resistor AC circuit has no phase change between the voltage and current.

And at the same time, the voltage lead the current by 90 degree with inductor. The current lead the voltage by 90 degree with capacitor.