Calculating LED Current in a Circuit with Given Voltage and Resistance

Understanding how to calculate the current through an LED (Light Emitting Diode) in a circuit is crucial for designing efficient and reliable electronic systems. This article will walk you through the steps of calculating the current when given a specific voltage, resistance, and LED voltage drop.

Understanding the Circuit

In a simple series circuit, the LED and a resistor are connected to a 9V power source. The LED has a voltage drop of 2V, while the resistor has a resistance of 100 ohms. The key to solving for the current lies in using Ohm's Law and understanding the relationship between voltage, current, and resistance in a series circuit.

Step-by-Step Calculation

Step 1: Determine the Voltage Across the Resistor

The total voltage from the power source is 9V. The LED has a voltage drop of 2V, so the voltage across the resistor is:

` Resistor Voltage (VR) Total Voltage (V) - LED Voltage Drop (VLED) Resistor Voltage (VR) 9V - 2V Resistor Voltage (VR) 7V `

This step uses the principle that the sum of the voltages across all components in a series circuit must equal the total voltage supplied by the power source.

Step 2: Apply Ohm's Law to Calculate the Current

Once we have the voltage across the resistor, we can use Ohm's Law to calculate the current flowing through the circuit:

` Current (I) Voltage (V) / Resistance (R) Current (I) 7V / 100Ω Current (I) 0.07A or 70mA `

Ohm's Law states that the current (I) is equal to the voltage (V) divided by the resistance (R). Since the circuit is in series, the current is the same through both the resistor and the LED.

Conclusion

By following these steps, you can easily calculate the current flowing through an LED in a series circuit with a given voltage and resistance. Understanding this process is fundamental for designing and troubleshooting electronic circuits, ensuring they operate effectively and safely.

Key Takeaways

Ohm's Law: Current (I) Voltage (V) / Resistance (R) Total Voltage: The sum of the voltage drops across all components in a series circuit equals the total voltage supplied. Circuit Design: Knowing the current allows for proper component selection and power management.

Related Keywords

LED current calculation voltage drop Ohm’s Law