University » Physics 327 » Lab 02
This lab report is based off of topic #1 as provided on the lab outline. This lab required the following:
Read the report from last week by Jon. He measured current through a diode for both forward and reverse bias. For reverse bias, he found very small currents, on the order of 5 μA. Again, measure current versus voltage for a 1N4148 diode. Do the measurements to higher precision than Jon did, and also extend the range to more negative voltages. However, do not destroy the diode by exceeding the reverse breakdown voltage.
My initial results were very similar to Jon’s results, in that I noticed a very slow increase up to a certain point, where the increase in current suddenly “took off” in comparison to the voltage gain. Here is the graph:
Focusing down onto the early values shows just how smoothly the data points increase in a power fashion:
When I graphed the results across the entire data range, the graph was as expected:
However, when I looked closer at just the negative values, they became very unusual:
It appears that negative voltages cause negative current flows in a direct linear fashion, whereas positive voltages caused a positive current in a power fashion! In fact, if we look closer at the negative values, a trendline can be extracted:
A trendline provided a value of y = 0.1005x-0.0076 where x is the voltage used and y is the resulting current.
My Setup:
Data:
| Voltage (V) | Current (mA) |
|---|---|
| -17.40 | -1.76 |
| -17.30 | -1.75 |
| -17.20 | -1.74 |
| -17.10 | -1.73 |
| -17.00 | -1.72 |
| -16.90 | -1.71 |
| -16.80 | -1.70 |
| -16.70 | -1.69 |
| -16.60 | -1.68 |
| -16.50 | -1.67 |
| -16.40 | -1.66 |
| -16.30 | -1.65 |
| -16.20 | -1.64 |
| -16.10 | -1.63 |
| -16.00 | -1.62 |
| -15.90 | -1.61 |
| -15.80 | -1.60 |
| -15.70 | -1.59 |
| -15.60 | -1.58 |
| -15.50 | -1.57 |
| -15.40 | -1.56 |
| -15.30 | -1.55 |
| -15.20 | -1.54 |
| -15.10 | -1.53 |
| -15.00 | -1.52 |
| -14.90 | -1.51 |
| -14.80 | -1.50 |
| -14.70 | -1.48 |
| -14.60 | -1.47 |
| -14.50 | -1.46 |
| -14.40 | -1.45 |
| -14.30 | -1.44 |
| -14.20 | -1.43 |
| -14.10 | -1.42 |
| -14.00 | -1.41 |
| -13.90 | -1.40 |
| -13.80 | -1.39 |
| -13.70 | -1.38 |
| -13.60 | -1.37 |
| -13.50 | -1.36 |
| -13.40 | -1.35 |
| -13.30 | -1.34 |
| -13.20 | -1.33 |
| -13.10 | -1.32 |
| -13.00 | -1.31 |
| -12.90 | -1.30 |
| -12.80 | -1.29 |
| -12.70 | -1.28 |
| -12.60 | -1.27 |
| -12.50 | -1.26 |
| -12.40 | -1.25 |
| -12.30 | -1.24 |
| -12.20 | -1.23 |
| -12.10 | -1.22 |
| -12.00 | -1.21 |
| -11.90 | -1.20 |
| -11.80 | -1.19 |
| -11.70 | -1.18 |
| -11.60 | -1.17 |
| -11.50 | -1.16 |
| -11.40 | -1.15 |
| -11.30 | -1.14 |
| -11.20 | -1.13 |
| -11.10 | -1.12 |
| -11.00 | -1.11 |
| -10.90 | -1.10 |
| -10.80 | -1.09 |
| -10.70 | -1.08 |
| -10.60 | -1.07 |
| -10.50 | -1.06 |
| -10.40 | -1.05 |
| -10.30 | -1.04 |
| -10.20 | -1.03 |
| -10.10 | -1.02 |
| -10.00 | -1.01 |
| -9.90 | -1.00 |
| -9.80 | -0.99 |
| -9.70 | -0.98 |
| -9.60 | -0.97 |
| -9.50 | -0.96 |
| -9.40 | -0.95 |
| -9.30 | -0.94 |
| -9.20 | -0.93 |
| -9.10 | -0.92 |
| -9.00 | -0.91 |
| -8.90 | -0.90 |
| -8.80 | -0.89 |
| -8.70 | -0.88 |
| -8.60 | -0.87 |
| -8.50 | -0.86 |
| -8.40 | -0.85 |
| -8.30 | -0.84 |
| -8.20 | -0.83 |
| -8.10 | -0.82 |
| -8.00 | -0.81 |
| -7.90 | -0.80 |
| -7.80 | -0.79 |
| -7.70 | -0.78 |
| -7.60 | -0.77 |
| -7.50 | -0.76 |
| -7.40 | -0.75 |
| -7.30 | -0.74 |
| -7.20 | -0.73 |
| -7.10 | -0.72 |
| -7.00 | -0.71 |
| -6.90 | -0.70 |
| -6.80 | -0.69 |
| -6.70 | -0.68 |
| -6.60 | -0.67 |
| -6.50 | -0.66 |
| -6.40 | -0.65 |
| -6.30 | -0.64 |
| -6.20 | -0.63 |
| -6.10 | -0.62 |
| -6.00 | -0.61 |
| -5.90 | -0.60 |
| -5.80 | -0.59 |
| -5.70 | -0.58 |
| -5.60 | -0.57 |
| -5.50 | -0.56 |
| -5.40 | -0.55 |
| -5.30 | -0.54 |
| -5.20 | -0.53 |
| -5.10 | -0.52 |
| -5.00 | -0.51 |
| -4.90 | -0.50 |
| -4.80 | -0.49 |
| -4.70 | -0.48 |
| -4.60 | -0.47 |
| -4.50 | -0.46 |
| -4.40 | -0.45 |
| -4.30 | -0.44 |
| -4.20 | -0.43 |
| -4.10 | -0.42 |
| -4.00 | -0.41 |
| -3.90 | -0.40 |
| -3.80 | -0.39 |
| -3.70 | -0.38 |
| -3.60 | -0.37 |
| -3.50 | -0.36 |
| -3.40 | -0.35 |
| -3.30 | -0.34 |
| -3.20 | -0.33 |
| -3.10 | -0.32 |
| -3.00 | -0.31 |
| -2.90 | -0.30 |
| -2.80 | -0.29 |
| -2.70 | -0.28 |
| -2.60 | -0.27 |
| -2.50 | -0.26 |
| -2.40 | -0.25 |
| -2.30 | -0.24 |
| -2.20 | -0.23 |
| -2.10 | -0.22 |
| -2.00 | -0.21 |
| -1.90 | -0.20 |
| -1.80 | -0.19 |
| -1.70 | -0.18 |
| -1.60 | -0.17 |
| -1.50 | -0.16 |
| -1.40 | -0.15 |
| -1.30 | -0.14 |
| -1.20 | -0.13 |
| -1.10 | -0.12 |
| -1.00 | -0.11 |
| -0.90 | -0.10 |
| -0.80 | -0.09 |
| -0.70 | -0.08 |
| -0.60 | -0.07 |
| -0.50 | -0.06 |
| -0.40 | -0.05 |
| -0.30 | -0.04 |
| -0.20 | -0.03 |
| -0.10 | -0.02 |
| 0.01 | 0.00 |
| 0.02 | 0.00 |
| 0.03 | 0.01 |
| 0.04 | 0.01 |
| 0.05 | 0.01 |
| 0.07 | 0.02 |
| 0.07 | 0.02 |
| 0.08 | 0.03 |
| 0.09 | 0.03 |
| 0.11 | 0.03 |
| 0.12 | 0.04 |
| 0.13 | 0.05 |
| 0.14 | 0.06 |
| 0.15 | 0.07 |
| 0.15 | 0.09 |
| 0.16 | 0.10 |
| 0.18 | 0.12 |
| 0.19 | 0.15 |
| 0.19 | 0.17 |
| 0.21 | 0.20 |
| 0.22 | 0.25 |
| 0.22 | 0.29 |
| 0.24 | 0.36 |
| 0.25 | 0.43 |
| 0.25 | 0.51 |
| 0.27 | 0.62 |
| 0.27 | 0.75 |
| 0.28 | 0.86 |
| 0.29 | 1.05 |
| 0.30 | 1.27 |
| 0.31 | 1.53 |
| 0.32 | 1.86 |
| 0.33 | 2.33 |
| 0.34 | 2.83 |
| 0.35 | 3.53 |
| 0.36 | 4.36 |
| 0.37 | 5.40 |
| 0.38 | 6.65 |
| 0.39 | 8.30 |
| 0.40 | 10.10 |
| 0.41 | 12.69 |
| 0.42 | 15.83 |
| 0.43 | 19.97 |
| 0.44 | 24.52 |
| 0.45 | 30.46 |
| 0.46 | 37.60 |
| 0.47 | 46.76 |
| 0.48 | 58.00 |
| 0.49 | 71.54 |
| 0.50 | 89.11 |
| 0.51 | 108.43 |
| 0.52 | 133.70 |
| 0.53 | 162.92 |