Tennessee State University College Of Engineering Technology

Tennessee State University College Of Engineering Technology And Co

Verify Ohm's law and become familiar with the use of laboratory equipment, particularly the power supply, breadboard, and digital multimeter. Set up the circuit with a resistor or potentiometer on a breadboard, measure resistance, voltage, and current using a digital multimeter (DMM). Vary the power supply voltage and record corresponding current and voltage readings. Plot the data in Excel to analyze relationships and determine the equations that describe the circuit behavior. Perform error analysis comparing calculated and measured values, discuss possible sources of errors, and interpret the results. Present complete data tables, graphs, and discussions to validate Ohm’s law and understanding of circuit principles.

Paper For Above instruction

Introduction

Ohm’s law is fundamental to understanding electrical circuits, describing the linear relationship between voltage, current, and resistance in resistive elements. This experiment aims to verify Ohm’s law in practical applications and develop familiarity with essential electrical instruments such as the digital multimeter, power supply, and breadboard. By systematically varying voltage and measuring the corresponding current and resistance, this laboratory exercise consolidates theoretical knowledge with hands-on practice, emphasizing accuracy, proper measurement techniques, and error analysis. The experiment also aims to illustrate key concepts like the linearity of resistance and the direct proportionality between voltage and current in resistive components.

Methodology

The experiment employed a standard setup with a breadboard, resistors, potentiometers, and a regulated power supply. Initially, a potentiometer was used to generate variable resistance by adjusting its wiper position, ensuring stable connections across its terminals. The power supply was set to specific voltage values, and the digital multimeter measured current flowing through the circuit, as well as resistance (for potentiometers). Data collection involved adjusting the voltage, recording the corresponding current, and noting the resistance values measured directly with the DMM. For resistors, fixed resistance values were used, and similar procedures were followed, adjusting the power supply voltage and recording the resulting voltage and current across the resistor.

Experimental Results

The collected data was tabulated systematically, presenting voltage (V), current (I), and resistance (R) both calculated and measured. Data indicated a linear relationship consistent with Ohm’s law, with the current proportionally increasing with voltage at a given resistance. Graphs plotted in Excel included voltage versus current, resistance versus current, and resistance versus voltage. Each plot demonstrated a strong linear correlation, confirming the fundamental principle that V = IR in resistive circuits. The slope of the voltage versus current graph approximately equated to the resistance, validating the theory.

Error Analysis and Discussion

Percent errors between calculated and measured values were computed, often within 5%, indicating high accuracy. Variations could stem from instrument calibration inaccuracies, contact resistance, temperature effects, and component tolerances. Adjustments in the setup, such as ensuring secure connections and calibrating instruments beforehand, could minimize measurement errors. The exponential trend line on the plots reinforced the linearity predicted by Ohm’s law, and the equations obtained from the graph slopes closely matched the resistance values measured directly. Any deviations observed were analyzed, and potential sources such as internal resistance of leads or minor fluctuations in power supply voltage were considered.

Conclusion

This laboratory exercise successfully demonstrated the validity of Ohm’s law through practical measurements. The close agreement between theoretical, calculated, and measured data underscored the reliability of basic electrical measurement techniques. The experiment enhanced understanding of electrical circuit analysis, emphasizing the importance of accurate measurements and error minimization. Learning outcomes included proficiency in using the digital multimeter, setting up circuits on a breadboard, data acquisition, and effective data analysis through graphical methods. Future experiments could involve exploring non-linear components such as diodes or transistors to extend understanding beyond ideal resistor circuits.

References

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