LED 3MM (White)

Description

The 3mm White LED is a small and efficient Light Emitting Diode (LED) that emits white light when current flows through it. White LEDs are typically made using a blue LED with a phosphor coating or a combination of multiple LEDs to produce white light. These LEDs are widely used in a variety of applications due to their compact size, brightness, and low power consumption.

Overview of 3mm White LED:

• Package Size: 3mm (a standard small LED size)
• Color: White (emits white light, typically a result of blue LEDs coated with phosphor or a mix of colored LEDs)
• Transparency: Transparent lens (typically made of clear plastic), allowing the light to be emitted without much color filtering or diffusion.
• Typical Forward Voltage: 3.0V to 3.5V (typically around 3.2V for white LEDs)
• Typical Forward Current: 20mA (standard operating current)
• Luminous Intensity: Typically 150-300mcd (millicandela), depending on the specific model.
• Power Dissipation: Low power consumption, typically around 0.06W.

Pin Configuration:

An LED typically has two pins:

• Anode (+): The longer leg (positive terminal).
• Cathode (-): The shorter leg (negative terminal).

For a 3mm White LED, the pinout is:

• Anode (+): Connect to the positive side of the power supply or circuit.
• Cathode (-): Connect to the negative side of the circuit (ground).

Electrical Characteristics of a 3mm White LED:

• Forward Voltage (Vf): The voltage drop across the LED when it is forward-biased (i.e., when current is flowing through it). For a white LED, this voltage is typically between 3.0V and 3.5V.
• Forward Current: 20mA is the typical current value used to drive the LED for optimal brightness. Going beyond the rated current can overheat and damage the LED.

Applications of 3mm White LED:

1. Indicator Lights:
   • 3mm white LEDs are commonly used as status indicators in various electronics, such as power-on indicators or functioning status lights.
2. Displays:
   • Used in seven-segment displays, digital clocks, or alphanumeric displays, where the white LED provides a bright and easily visible display.
3. Lighting:
   • Decorative lighting in electronics, signs, or small lamps. White LEDs are often used in LED strips or accent lighting to create uniform, bright illumination.
4. Automotive Lighting:
   • Many automotive applications use white LEDs for dashboard lights, headlight indicators, and interior lighting.
5. Toys and Gadgets:
   • Commonly found in toys, gadgets, and other consumer electronics where small, bright lights are needed.
6. Signals and Alarms:
   • White LEDs can be used for signal lights or as part of alarm systems for visual signaling.
7. Status Indicators:
   • White LEDs are used in electronic devices to show that the system is in an active state, powered on, or functioning normally.

Current Limiting Resistor:

When using a 3mm White LED, it’s important to use a current-limiting resistor to prevent excessive current that could damage the LED. The resistor helps limit the current flowing through the LED to a safe level.

How to Calculate the Resistor Value:

The general formula for calculating the current-limiting resistor for an LED is:

R=Vsupply−VfIfR = \frac{V_{supply} – V_f}{I_f}

Where:

• V_supply is the voltage supplied to the circuit.
• V_f is the forward voltage of the LED (typically 3.2V for white LEDs).
• I_f is the desired forward current (typically 20mA = 0.02A).

Example:

If you are using a 5V power supply:

• V_supply = 5V
• V_f = 3.2V (white LED forward voltage)
• I_f = 20mA (typical forward current)

Substituting the values into the formula:

R=5V−3.2V0.02A=1.8V0.02A=90ΩR = \frac{5V – 3.2V}{0.02A} = \frac{1.8V}{0.02A} = 90\Omega

So, you would need a 90Ω resistor in series with the LED. A 100Ω resistor is a standard and commonly available value and will work well.

Brightness and Efficiency:

• Luminous Intensity: The brightness of a white LED is typically measured in millicandela (mcd). A typical 3mm white LED has a luminous intensity of around 150 to 300mcd, depending on the specific model and manufacturer. This makes it bright for its small package size.
• Power Consumption: The power consumed by the white LED is typically low (in the range of 0.06W for typical current values). White LEDs are known for their energy efficiency, making them suitable for low-power applications.