The term **LED545** typically refers to a specific form factor or a standardized part number often associated with **high-power LED modules** or **T0-5 / T0-18** style packages used in specialty lighting and fiber optics. Below is a breakdown of the electronic components and characteristics associated with these LEDs. --- ### 1. Physical Structure and Packaging Most components labeled under the "545" series (or 5.45mm diameter packages) consist of the following physical parts: | Component | Description | Function | | :--- | :--- | :--- | | **Epoxy Lens** | Clear or diffused plastic dome | Focuses the light beam (Viewing angle) | | **Anode (+)** | Long lead wire | Positive electrical connection | | **Cathode (-)** | Short lead wire / Flat edge on rim | Negative electrical connection | | **Reflector Cup** | Metal frame housing the die | Reflects light forward to increase intensity | | **Semiconductor Die** | The actual PN junction chip | Converts electrical energy into photons | --- ### 2. Electrical Specifications While exact specs vary by manufacturer (e.g., Kingbright or Lumex), standard electronic parameters for these types of LEDs include: * **Forward Voltage ($V_f$):** * Red/Yellow: 1.8V – 2.2V * Blue/White/Green: 3.0V – 3.6V * **Forward Current ($I_f$):** Typically **20mA** for standard indicators or up to **100mA+** for high-output versions. * **Wavelength ($\lambda$):** Determines the color (e.g., 630nm for Red, 525nm for Green). * **Luminous Intensity ($I_v$):** Measured in mcd (millicandela). --- ### 3. Circuit Configuration To use an LED545 in an electronic circuit, you must include a **Current Limiting Resistor** to prevent the component from burning out. #### Calculation Formula: $$R = \frac{V_{source} - V_f}{I_f}$$ **Example Circuit Code:** ```cpp // Basic Arduino Blink Code for LED545 void setup() { pinMode(13, OUTPUT); // Connect LED545 Anode to Pin 13 (with resistor) } void loop() { digitalWrite(13, HIGH); // Turn LED on delay(1000); // Wait 1 second digitalWrite(13, LOW); // Turn LED off delay(1000); // Wait 1 second } ``` --- ### 4. Common Applications * **Fiber Optic Transmitters:** Due to the precise 5mm/5.45mm housing. * **Status Indicators:** Used on PCB control boards. * **Sensors:** Infrared versions of the 545 package are used in smoke detectors and proximity sensors.