Resistor Calculations in LED Circuits

The video tutorial explains how to calculate the resistor value in LED circuits using Ohm's Law. It covers three scenarios: a single LED circuit, a series LED circuit, and a parallel LED circuit. For each scenario, the video provides step-by-step calculations, including converting milliamps to amps and determining the voltage across the resistor. The tutorial emphasizes understanding the relationship between voltage, current, and resistance in different circuit configurations.

What is the forward voltage of the LED mentioned in the introduction?

• 2 volts

• 3 volts

• 4 volts

• 5 volts

In a single LED circuit, what is the formula to calculate the resistor value using Ohm's Law?

• Voltage divided by current

• Current times resistance

• Current divided by voltage

• Voltage divided by resistance

What is the calculated resistor value for a single LED circuit with a forward voltage of 3 volts and a current of 50 milliamps?

• 120 ohms

• 100 ohms

• 150 ohms

• 200 ohms

In a series circuit with multiple LEDs, what is the total potential difference across the LEDs if each has a forward voltage of 3.6 volts?

• 12 volts

• 10.8 volts

• 7.2 volts

• 3.6 volts

What is the resistor value needed for a series circuit with three LEDs, each having a forward voltage of 3.6 volts and a current of 30 milliamps?

• 50 ohms

• 40 ohms

• 60 ohms

• 30 ohms

In a parallel circuit with identical LEDs, how is the total current through the resistor calculated?

• Sum of individual currents

• Product of individual currents

• Average of individual currents

• Difference of individual currents

What is the resistor value needed for a parallel circuit with three LEDs, each having a forward voltage of 4 volts and a current of 20 milliamps?

• 120 ohms

• 100 ohms

• 133 ohms

• 150 ohms

What is the total current flowing through the resistor in a parallel circuit with three LEDs, each drawing 20 milliamps?

• 60 milliamps

• 40 milliamps

• 20 milliamps

• 80 milliamps

What is the voltage across the resistor in a parallel circuit if the source voltage is 12 volts and the forward voltage of each LED is 4 volts?

• 6 volts

• 10 volts

• 4 volts

• 8 volts

What is the main takeaway from the video regarding resistor calculation in LED circuits?

• Always use the same resistor value

• Resistor value depends on the circuit configuration

• LEDs do not require resistors

• Resistor value is irrelevant