Why is a resistor connected in series with an LED?

Connecting a resistor in series with an LED is crucial for controlling the current flowing through the LED. LEDs have a specific voltage drop across them when they are forward-biased and conducting, and they are sensitive to excessive current. Without a resistor, the current can exceed the maximum rating of the LED, leading to overheating and ultimately damaging the device.

The resistor limits the current, ensuring it stays within safe operating levels. This is essential because if too much current flows through the LED, it can cause permanent damage due to the increase in temperature or exceed the LED's voltage rating, which would destroy the junction where light is produced.

Thus, the primary role of the series resistor is to protect the LED from high current or voltage, preserving its functionality and extending its lifespan. This makes the correct choice valid, as it highlights the importance of maintaining appropriate operating conditions for the LED.