Day 24 AC Circuits

RMS and AC current and Voltage:

Day 23 Inductors

Inductors:

In this lab we were ask to set up a a circuit, which include inductor and resistance and function generator.

Umm~ Calculation Error ~ correct one will be posted later.

Below is the gotten data:

Day 22 Solenoids

Solenoids:

This experiment we use plastic tube and wrapped wire to attach the power supply with a coil.

Begin with 1 loop and increase 1 loop at once till 5 loops.

We set magnetic field sensor inside the tube to make sure sensor is below( we didn't do above) the center of coil. 

Result below:

As the result, we can see the ratio of the magnetic field is decrease as loop increase, and it drop till 3.5*10^-5 T/A.

By using this value we can calculated the length of wire by formula below (Solenoid)

Magnet in Motion:

We connect this large coil to ammeter to induce current. We discover the relationship below

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Extra Credit

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Day 21 Earth's Magnetic Field

Magnetic Field of Earth:

We set up the tool above to determine the magnetic field of the Earth.

Using Biot-Savart Law we calculated the magnetic field for the coil using current, the number of coil turns, radius and the constant.

Then we used the relationship between Earth field, and coil field to determine the field.

We determined by using the compass changing degree and known current to solved for the magnetic field of Earth by dividing the magnetic field of the coil by tangent theta. As the graph below we knew that the slope of the data set would be the magnetic field of the earth.

 

Day 20 Motor

Magnetic Motor:

With Power supply the magnetic motor spin clock-wisely.

Switch the magnetic cause it spin counter wisely.

Self-Made Magnetic Motor:

Over here, we create our own magnetic motor with copper wires, paper clip, Disney cup,magnetic, and power supply.

First, we wrapped wire to get a symmetric circular.

Second, we used sand paper to sanded 180 degree for one end of wire, and 360 degree for another end of wire.

Third, We attached paper clip to the bottom of cup and place magnetic in the center.

Forth, attach power supply to the paper clip and set the symmetric circular wire on the paper clip.

Last, turn the power supply on, and let it spin.

Day 19 Magnetic Field

Magnetic Field:

By using compass, we can see the magnetic vector in each position, and the result is magnetic vector goes out at south back at north.

Using this we can easily seem the magnetic filed by steal powder.

These three graph show the magnetic field is similar to electric field but represent differently. It represent positive and negative with north and south.  

Vector relationship between F,v,and B

As we know, the magnetic force is equal to I (current) * l (distance) "CROSS" B (magnetic field).

In order to solve B we can replace force by ma + mr^2; however, even we solve the answer, the unit become confusing.

Magnetic Field involve rotation:

Here comes the rectangle wire relationship that magnetic field crossed in two different ways.

Here comes the calculation of magnetic filed under X-Y-Z vectors.

Day 18 Transistor

Transistor and amplifier

We were asked to build a electric circuit~!!

With above setup and amplifier 3kHZ, frequency 0.3 V with 2N3904 transistor, we got the graph below.

Here comes two waves by function generator.

It shows original V as 0.3 V and another one above with 20V~30V.

It means the set up one has 100 times bigger than original.

Semiconductor Lab:

Using the graph above to set up the circuit.

This is the setup we finally be able to here the music 

Day 17 Electronic

Measuring changing voltage:

In this lab, we set the function generator to 96 HZ then we got the graph above. We were asked to get the experimental and theoretical period which is T(period) = 1/f .
For theoretical : T = 0.0104
For experimental: T = 0.01
However there are no different between DC & AC

Triangular

Rectangular

Graphs above are the function generator triangular and rectangular setting, and both of them are 96 HZ.

DC Power Supply:

We were asked to find amplitude and period, but this graph make us hard to find it.

AC Transformer:

Amplitude: 20 V
Period: 0.017
frequency: 58.8 HZ

Lissajous Figure (AC Transformer)

frequency: 30 HZ

But we set it to oscilloscope in XY mode which come up with Lissjous figures.

frequency: 60 HZ
Shape was circular or oval.

Mystery Box:

We were asked to solve which one is useful one which can create waves or frequencies shape.

Red and Black

 

Square Frequency

Amp = 4V

Period = 0.0044s

Red and Blue

Square Frequency

Amp = 1.8V

Period = 0.0043 s

Red and Green

Square Frequency

Amp = 4V

Period = 0.0042s

Blue and Black

Random Frquency

Amp = 0.02 V

Period = 0.003s

Green and Black

Sinusoidal square Frequency

Amp = 0.008 V

Period = 0.0044s

Result:

Yellow : none complete wave

Rest determine the combination of square and sinusoidal frequencies.

Day 16 RC Circuit

Quantitative Measurement on RC System: 

For this experiment, we were asked to create RC circuit with a resistor with resistor, power supply, and capacitor. We used logger pro to measure the voltage, and before we also make some prediction that the potential voltage and time should be inversely related. As the result below, we were right.

On discharge(pink) one, we know that B in the natural exponential equation should be vary close to zero. However, the Amp should be close to 4.5 V (original V from power supply). For conclusion, C as our charge time should be the same for both discharge and charge.

To be able to find out the C value which is 0.003620 sec by theoretically method. We first used multimeter to determine the resistance of our resistor. (R = 2.15 k"omega") 

We next used their relationship that Time =1/Resistance*Capacitance to solve the value of charge time. 

As the result, t=0.00465 sec, it mean there were about 22% error. This error might come from the capacitors value straight off the labeling. Below is our calculation. 

Day 15 Capacitors

Self Made Capacitor:

For experiment we place to aluminum foil between physic book's pages. The foils were connected to the multimeter to be able to determine the capacitance. As area remain the same the thickness of pages act like distance, which cause the change of capacitance. We have tested 1, 10, and 20 pages and notice smaller distance cause bigger capacitance.(Graph below)

Capacitors in Series & Parallel:

For this experiment we given two resistor, we measured each capacitance which come up two solutions. 1st the parallel resistor come up the solution equal to their sum. But for series the capacitance is equal to Csum = 1/C1 +1/C2.