What happens when a LED is connected with incorrect polarity?

When a light-emitting diode (LED) is connected with incorrect polarity, it typically cannot conduct current and can overheat as a result. LEDs are designed to allow current to flow in one direction only, which is from the anode to the cathode. When the LED is reverse-biased (connected backwards), it may not glow and can instead experience excess voltage.

If the reverse voltage exceeds the LED's breakdown voltage, it can lead to a phenomenon known as reverse breakdown, which causes the LED to fail or 'burn out' due to excessive current flow. In many cases, this results in permanent damage to the LED, rendering it non-functional. This is why connecting an LED with incorrect polarity generally leads to burnout rather than normal operation or exhibiting other behaviors.

Understanding how LED polarity affects performance is crucial for proper use in electronic circuits, ensuring that the components function as intended and preventing damage.