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.