Understanding LEDs

This video tutorial explains the basics of LEDs, including their efficiency in converting electrical energy to light energy, and how to properly connect them in a circuit. It covers the importance of understanding LED polarity, the need for a current-limiting resistor, and factors to consider when purchasing LEDs, such as forward voltage, maximum current, and luminous intensity. The video also demonstrates how to calculate the appropriate resistor value using Ohm's Law and presents an experiment to show the relationship between voltage and current in an LED circuit.

What is the primary function of an LED?

• To store electrical energy

• To amplify electrical signals

• To convert light energy into electrical energy

• To convert electrical energy into light energy

Which terminal of an LED should be connected to the positive terminal of a battery?

• Cathode

• Neither terminal

• Anode

• Both terminals

Why is it important to use a current-limiting resistor with an LED?

• To prevent the LED from overheating and burning out

• To allow current to flow in both directions

• To decrease the voltage across the LED

• To increase the brightness of the LED

What is the typical forward voltage drop for a green LED?

• 4.5 volts

• 3.3 volts

• 2.2 volts

• 1.5 volts

Which factor does NOT need to be considered when buying an LED?

• Luminous intensity

• Color of the LED

• Forward voltage drop

• Maximum recommended current

How do you calculate the resistance needed for an LED circuit?

• Multiply voltage by current

• Divide voltage by current

• Add voltage and current

• Subtract current from voltage

In the given circuit, what is the potential difference across the resistor if the LED's voltage drop is 2.2 volts and the battery is 9 volts?

• 6.8 volts

• 7.8 volts

• 8.8 volts

• 9.8 volts

What happens to the forward voltage drop across an LED as the current increases?

• It decreases

• It remains constant

• It increases

• It fluctuates randomly

What is the effect of increasing current on the brightness of an LED?

• The LED turns off

• The brightness increases

• The brightness decreases

• The brightness remains the same

What is the risk of exceeding the maximum recommended current for an LED?

• The LED will become more efficient

• The LED may burn out

• The LED will change color

• The LED will become dimmer