Day 21- Magnetic Field of the earth

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The makeshift contraption above was used in order to determine the magnetic field of the earth.

Our group used what we knew about the Biot-Savart Law in order to calculate the magnetic field of the coil using the current, radius, number of turns, and the constant given. The relationship between the magnetic field from the earth and coil were used to determine this field. We based our calculation of the field based on the direction the compass was pointing, measured approximately in degrees. W had a known current and solved for the earth's field by dividing the coil's field by the tangent theta. The graph of the coil's field vs tangent theta is given below:

We used a general line of best fit and the slope was 1.055*10^-5 T

 

Day 20 - Motors & Magnetic Field Lines

Magnetic Motor Lab

Attaching the power supply to the motor caused it to spin.

Reversing the current's direction causes it to spin in the opposite direction.

Our Motor

The motor that our group created was composed of copper wire, several magnets and paperclips, and a power supply. A symmetrical oval shape was formed from the wire. One lead was sanded down 360 degrees while the other lead was sanded down half that amount. The paper clips were used as mounting points for the copper wire and placed on the top of the cup, and a magnet was placed inbetween the contraption as shown above. The current from the power supply is what moves the current through the wire and causes it to turn.

Day 19 - Magnetic Field

Magnetic field about a bar

We used a compass in order to find the magnetic north of the magnet. We indicated where the north and south poles were, and drew arrows around the magnet to represent the direction of the magnetic field. 

  

Visual representation of Magnetic field with ancient technology.

Magnetic Field and Rod

Attempt at solving for the magnetic field B for the metal rod. The units did not work out very well.

Magnetic Field with rotation

Calculation of Magnetic Field

Day 18 - Diodes and Transistors

We were able to create an amplifier on the breadboard shown below, according to the diagram shown above:

This breadboard set up created an amplifier that increased a 3,000Hz wave at 0.3 V with a transistor of 2N3904

This resulted in a 100 times amplification from the original.  The two waves on the screen are the wave being emitted by the function generator, as well as the amplification from the breadboard. The original voltage was 0.3 and the new one was 20-30 V.

We created the amplifier below based on the diagram shown above, using an LM386 audio amplifier

This set up finally did produce sound that we streamed from an alternative rock soundtrack from Bianca's phone, but it was mainly static.

Day 17 - Electronics and mystery box

Measuring Delta V

For this experiment we attached a function generator to the oscilloscope and set it to a frequency of 96Hz. We got the sine wave above as our result. We needed to find the theoretical and experimental period. To find the theoretical period we used the formula t=1/f. T is the period. We knew the frequency since we set it, so we plugged it in and got a period of .010417 s. We found a value of 5.1 for the wave's period and divided it by the time of 2 milliseconds. This gave us our experimental period of .0102 s, which is very close to the theoretical period. 

The two photos below are what occurs when the sine wave is changed to a triangle wave or square wave, respectively.

DC power supply

Our goal was to find the amplitude and period for this part. We found the amplitude to be 39 mV, while we were unable to find the period.

                                                                                                   AC Transformer

For alternating current, we needed to find the amplitude and period again. This was feasible since it was in the form of a sine wave. The amplitude was 20V and the period was .01702 (8.51*.002). The frequency was found to be 58.8 Hz

                                                 lissajous figures

The same alternating current transformer was connected to ch 1 and the function generator was connected to ch 2. The generator's frequency was set to 30 Hz and the oscilloscope was set in such a fashion that we could see the lissajous figured in the XY mode, for the two channels. The figure shown above was at 30 Hz, and it rotated and twisted as time passed.

In the photo above, the shape was an oval after we set the function generator to 60 Hz, and it should be noted that this one also rotated.

Mystery Box:

We had to decipher a Mystery box by determining which waves and frequencies it had. Our findings are below:

Red and Black

Square Frequency

Amplitude=4 V

Period=0.0044 s

Red and Blue

Square Frequency

Amplitude=1.8 V

Period=0.0043 s

Red and Green

Square Frequency

Amplitude=4 V

Period=0.0042 s

Blue and Black

Square/Sinusoidal Frequency

Amplitude=0.02 V

Period=0.003 s

Green and Black

Sinusoidal/Square Frequency

Amplitude=0.008 V

Period=0.0044 s

Other color combinations were possible, but nothing good came out of them worth mentioning. The yellow outlet did not produce any visible waves in combination with the others. The same goes for other combinations that were not mentioned. We were able to infer from this that the mystery box had both sinusoidal and square frequencies in it.

Day 16 - RC circuits

Quantitative Measurements on an RC System

Our experiment required that we make an RC circuit with a power supply, resistor, and capacitor in series. The resistor is used to slow down the charge time in order to make it more clear. The capacitor was shown on logger pro via a voltage measuring lead. Our group was able to initially predict that there would be an inversely proportional relationship between Potential and Time. This is shown on our graph below.

Based on the graph of the Discharge represented by the lower pink curve, we were able to conclude that the value of the constant B in the exponential equation should be close to zero. Also, the value for A in the equation should be close to the original voltage of 4.5 volts from the power supply.  Finally, the charge time should be the same for both the charge and discharge.

We found our experimental Charge time to be C=.00362 seconds. The theoretical charge time was found by using an actual measured resistance value of 21,500 ohm's, and plugging it into the equation tau=1/RC. With the capacitance known we found the theoretical time to be .00465 seconds. This was a 22 percent error deviation from our measured value. This is most likely due to the fact that some of our capacitor values were based on what they were labeled which were incorrect.