After that the students were asked to calculated the hot and cold resistance of a lightbulb if it has a given voltage put through it and it having a certain wattage when it is on/hot. Here is the work and it was determined that the hot resistance was 192 ohms. For the cold resistance our group left it as a function of length and radius of the filament, which would be less that 192 ohms once the lightbulb cooled.
After this problem, the Resistors and Ohms Law - Voltage-Current Characteristics lab was started and it was designed to experimentally show that real resistors will start to vary as the power that it dissipates increases. The equipment used in the lab was a multimeter, a varying voltage source (the digital analog on the diligent software) and a 100 ohm resistor which actually measured as 99.2 ohms. Here is a picture of the set up where the laptop was used to vary the voltage output and the multimeter measured the current and the voltage across the resistor.
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| The raw data of the current and voltage on the resistor |
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| Graph of the raw data with a best fit line The equation is current[mA] = 8.9376(voltage) -.0958 |
After the lab was finished, there was a question of how many loops, branches, and nodes were in a given circuit. Our group determined that there was 5 nodes, 3 loops, and 7 branches.
The next problem was to determine the current going through a certain circuit in difference setting of set voltage sources. The first current was 6 amps, the second current was 4 amps, the third current was 1.5 amps, and the final current was 3.5 amps.
Next was a lab, the Dependent Sources and MOSFETs lab, which is supposed to give an introduction to physical device that are dependent on circuit elements to operate. The dependent controlled source is the MOSFET and will be used to
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