LED vs LCD: Key Differences Explained

This article clarifies the differences between LED (Light Emitting Diode) and LCD (Liquid Crystal Display) technologies. Below, we’ll break down the key characteristics of each.

LED (Light Emitting Diode)

• Principle of Operation: Electro-luminescence. In simpler terms, it emits light when an electric current passes through it.

• Applications: Remote controls, display devices, and opto-couplers. You’ll find LEDs everywhere!

• Material: Fabricated using direct band gap material.

• How it Works: When properly excited, the LED emits light due to a large number of recombinations at the junction.

• Light Color: The color of the light emitted depends on the concentration of dopants used in the material.

• Operating Condition: Must be operated under forward biased condition.

• Optimal Current: With a forward current of around 20mA, an LED will give its maximum light intensity.

• Reverse Bias: In reverse bias, it behaves like a normal diode.

• Power Dissipation & Response Time: Power dissipation is typically measured in milliwatts (mW), and the response time in microseconds (µsec).

• Cut-in Voltage: The cut-in voltage is around 1.3V.

• Lifespan: Typically, an LED will have an operating life of 100,000+ hours. That’s a long time!

LCD (Liquid Crystal Display)

• Principle of Operation: Dynamic scattering of light. Instead of emitting light, it controls the passage of light.

• Applications: Primarily used as a display device to show characters, numbers, and images.

• Material: Uses liquid crystal material in its construction.

• Power Dissipation: Power dissipation is on the order of microwatts (µW). Very energy efficient!

• Response Time: Response time is in milliseconds (msec), which is slower than LEDs.

• Lifespan: Typically, an LCD will have an operating life of 50,000+ hours. Still quite long-lasting.