Current Sense Resistor Experiment

Objective

The goal of this experiment is to measure current in a circuit using a current sense resistor and analyze how the voltage across the resistor can be used to determine the current flow.

Components Required

• 1 x Current Sense Resistor (Low value, e.g., 0.1Ω or 1Ω)
• 1 x Multimeter (voltage measurement mode)
• 1 x Power Supply (DC Source)
• 1 x Load (Resistor or LED)
• 1 x Breadboard
• Connecting Wires

Theory

A current sense resistor is placed in series with the load in a circuit to measure the current. By measuring the voltage drop across the resistor, Ohm’s law (V = IR) can be used to calculate the current. Since the value of the current sense resistor is known and usually very small, the voltage drop is proportional to the current.

Circuit Diagram

Experimental Setup

1. Place the current sense resistor in series with the load in your circuit (e.g., LED or resistive load).

2. Connect the power supply across the circuit to provide DC power to the load.

3. Connect the multimeter across the current sense resistor to measure the voltage drop.

Procedure

1. Set up the circuit with the current sense resistor in series with the load (e.g., LED).
2. Turn on the power supply and ensure the circuit is operating properly.
3. Use the multimeter to measure the voltage drop across the current sense resistor.
4. Record the voltage value and use Ohm’s law (V = IR) to calculate the current flowing through the circuit.
5. Change the load (e.g., adjust the resistance) and observe how the current measurement changes.

Results and Observations

Document the voltage across the current sense resistor and calculate the corresponding current at different load conditions. Analyze the accuracy of the current measurement based on the small voltage drop across the sense resistor.

Conclusion

In this experiment, we demonstrated how a current sense resistor can be used to measure current in a circuit. By measuring the voltage drop across a small resistor, it is possible to accurately calculate the current using Ohm's law.