The purpose and objectives of this lab was to be able to draw completed electrical circuits using the correct symbols for selected electrical components, including batteries and diodes. Another focus was to calculate the proper resistance using Ohm’s law, use proper electrical currents and quantities, and lastly measure voltage and resistance in an electrical circuit using a multimeter. Materials: Wire Light Emitting Diodes (red, green, blue) Alligator Chips Resistors Multimeter 9-volt battery Procedures:
With the components provided in the lab kit, “build” the DC series circuit. 2. Using the resistors provided, that limits the current to less than 20 ma, use the multimeter to measure the voltage drops across each component in the circuit. 3. When using the multimeter to measure, start with the highest scale and work down to the scale that provides the most readable voltage value. Record the data found in an Excel spreadsheet. 4. Use the voltage drops across the resistor and the value of the resistor to calculate the current flow through the resistor.
With Excel and the values found for the voltage across the LED and current through the LED, plot a graph to determine if the LED obeys Ohm’s Law. Data: Calculations: LED Resistor Value: R = (VS – VL) / I Vs: supply voltage VL: LED voltage I: LED current R: resistance of the resistor Ohm’s Law: R = V/I V: voltage across the resistor I: current through the resistor R: resistance of the resistor Results: The plot of the current shows a straight, linear line. This determines that the LED obeys Ohm’s Law.
This experiment allowed one to develop the knowledge and skill of creating a functional circuit by first learning about each electronic component that plays a role in maintaining a circuit. These components included resistors, which limit the flow of electric current, a multimeter, which was used to measure the voltage drops, diodes, and LEDs that convert electricity to light. The theory of the lab was to observe and record information found in the relationship between light frequency and the energy of the light. As indicated in the results and the plotted graph, the LED obeys the Ohm’s Law.
We know this because of the straight, linear line that was created by voltage vs. current. The slope of the line represents the steady increase of the resistance. One can be confident that this line represents the resistance and is in turn an accurate depiction for the value of the resistor. Because this lab dealt with new instruments and was very hands on, the risk of error was greater. Error in the results can be the misuse of the multimeter or recording the wrong observations. Creating the circuit could have also been set up incorrectly or could have been low quality due to lack of experience.
Looking back at the theory and objectives of this lab, I believe I did meet the purpose of this experiment. Through trial and error I conducted a current where I could visualize and analyze all the components that go into creating a current. To modify the procedure, I would add more direction and “how to,” to better the understanding of the next student. The pictures used in the lab really helped to complete all procedures. References: Giancoli, D. C. (2006). Physics (6th ed. ). Upper Saddle River: Pearson Prentice Hall.