6/2/2014 RMS and AC Current and Voltage

Capacitor in AC-circuit

In this part, we are connecting the function generator that producing AC current and square function in 10Hz(20Hz) across the capacitor with a current probe in series with the capacitor as show in picture above.  We also connect the current sensor and voltage sensor with the circuit to measure the current follow through the circuit and voltage changed across the capacitor.  

Current vs time & Potential vs time graph.  We can find the maximum current and maximum voltage from the graph.  We then going to use the data to calculate the RMS current, RMS voltage and reactance.

First, we are applying the equations as show in the picture to calculate the theoretical reactance(Xc) and RES current(Irms).  Second, we calculate the actual Irms and Xc base on our experiment data to compare with the theoretical Irms and Xc.  When we set the frequency at 10Hz, our actual reactance is different than the theoretical value.  When we set the frequency at 20Hz, our actual reactance almost equal to the theoretical reactance.  

Inductor in AC-Circuit

In this part, we are connecting the function generator that producing AC current and square function in 10Hz across the inductor with a current probe in series with the inductor.  We also connect the current sensor and voltage sensor with the circuit to measure the current follow through the circuit and voltage changed across the inductor.  

Current vs time & Potential vs time graph as show in pictures below.  We are using the state function in Logger Pro to find the maximum current and maximum voltage from the graph.  We then going to use those datas to calculate the RMS current, RMS voltage and resistance in inductor.

Part 1: Inductor Without Iron Core

Part 2: Inductor With Iron Core

5/28/2014 Inductance & Active Physics(E)

Inductance

Active Physics

5/19/2014 Solenoid & Magnetic Field in Motion

Solenoid

In this experiment, we are rolling turns of wire on a plastic rod and place it around the magnetic field sensor to measure the magnetic field that created by moving current.  

Recorded magnetic field created by different turns of coil.  Base on the data to calculate the length of solenoid which is many turns of coil.  But the values of the strength of the magnetic field were not very reliable because of the orientation of the sensor.

Measured data by Professor Mason.  

Magnetic Field in Motion

We were given a coil of wire, galvanometer, and bar magnet in order to experiment with electromagnetic induction. 

We are moving the bar magnet in and out of coil of wire in this experiment.  Base on observation we found that factors such as the number of coils and the velocity in which we moved the magnet in and out of the coil contributed to the amount of current we measured.  

5/15/2014 Finding The Magnetic Field of Earth

Finding Earth Magnetic Field

We are connecting power supply with coil to produce magnetic field.  Base on the know values such as current, turns of coil, and change of angle on the compass when the magnetic field created by the coil.  

Recorded experiment data.  In order to determine this we used the deflection of the compass at a know current and solved for the magnetic field of the earth by dividing the magnetic field of the coil by tangent of theta.

Once we fit a linear line onto our data that the slop of the data set would be the magnetic field of the earth which was about 1*10^-5 T.

5/12/2014 Motors and Magnetic Field

Magnetic Motor

We connect the power supply to the motor and it began to spin.  When we reversed the direction of current it began to spin in the opposite direction.  

Homemade Magnetic Motor

We created a magnetic motor by using a copper wire, magnets, two paperclips, and a power supply. First we wrapped the wire as show in picture, then sanded 360 degrees of one lead of the wire and 180 degrees of the other lead to remove the paint on it. We attached the paper clips on the table and placed a magnet in between. Finally, we connect the power supply to the paperclips and rested the wire leads between the loops. When we turned on the power supply it began to spin which is caused by the current and magnetic field.  

The video of our homemade magnetic motor.  It works grate.  

5/8/2014 Magnetic Force and Field

Activity 1: Field Directions Around a Bar Magnet

We are using a small compass to map out the magnetic field surrounding a large bar magnet and denote the directions of the field with arrows.  

A series of magnetic field lines with direction that point from north pole to south pole around the magnet.  We draw three closed loops which one loop enclose no magnetic pole(L1), another loop enclose one of the poles(L2), and another enclose both poles(L3) to show the net flux of each loops.  Recorded net flux in each loops on the right side of the picture.  

Actual magnetic field produce by the bar magnet.  

Activity 2: Calculate the Magnetic Field

Calculate the magnetic field produce by the U-shaped magnet acted on the copper hoop when current going through.  

 Using experiment data to calculate the magnetic field.  We have calculation error in calculating the force which Force in not equal to m*a+I*alpha.

I use the energy method to calculate the magnetic force.  

5/5/2014 Diodes and Transistors

One Transistor Amplifier

Base on the circuit as show to recreate a real circuit on the bread board.    

Using a 2N3904 transistor with resistors and capacitors to create an amplifier.

The two waves on the screen show the voltage supplied by the function generator(top wave) and its output(bottom wave) after amplification of the breadboard circuit.  By readying the result on the screen, we can say an amplification emitted about 100 times the original supplied.

Amplifier with Gain = 20 (Minimum Parts)

Base on the this circuit diagram to create an amplifier with a signal semiconductor.  

 The amplifier that we created on the bread board.  

Connecting the amplifier with power supply and speaker to play music from cell phone.  After we try to connect to several different speaker, we finally heard the music that playing on my phone from the speaker.