The **TOM-3046L-R** is a specific optoelectronic component, primarily categorized as a **Dot Matrix Display**. These components are widely used for displaying alphanumeric characters, symbols, and simple graphics in embedded systems. Below is a detailed breakdown of its electronic specifications and characteristics. --- ### 1. General Overview The TOM-3046L-R is a **5x7 LED Dot Matrix Display**. It consists of 35 individual light-emitting diodes (LEDs) arranged in 5 columns and 7 rows. | Parameter | Specification | | :--- | :--- | | **Array Size** | 5 x 7 | | **Dot Diameter** | Approx. 3.0mm (0.12 inch) | | **Display Color** | Red (typically High Efficiency Red) | | **Circuit Type** | Row Cathode, Column Anode (standard configuration) | | **Surface Color** | Black face with white dots (for high contrast) | --- ### 2. Electrical Characteristics To operate the TOM-3046L-R safely, you must adhere to the following typical electrical ratings (based on standard T-Series Red LEDs): | Characteristic | Symbol | Typical Value | Unit | | :--- | :--- | :--- | :--- | | **Forward Voltage (per LED)** | $V_F$ | 1.8V - 2.2V | V | | **Forward Current (per LED)** | $I_F$ | 20mA | mA | | **Peak Forward Current** | $I_{FP}$ | 100mA (1/10 Duty Cycle) | mA | | **Power Dissipation** | $P_D$ | 75mW | mW | | **Reverse Voltage** | $V_R$ | 5V | V | --- ### 3. Pin Configuration and Driving Logic The device is driven using a **multiplexing** technique. Because there are 35 LEDs but only a limited number of pins (usually 12 to 14 pins), the LEDs share connections. * **Row Cathode / Column Anode:** * To light a specific dot, you apply a positive voltage (HIGH) to the specific **Column** pin and a ground (LOW) to the specific **Row** pin. * **Scanning:** * Since dots share rows/columns, you cannot turn on every individual dot simultaneously with unique patterns. Instead, you "scan" through the rows very quickly (faster than the human eye can see) to create the illusion of a steady image. --- ### 4. Typical Applications * **Industrial Controllers:** Displaying status codes or temperatures. * **Clocks and Timers:** Small-scale digital readouts. * **Elevator Indicators:** Showing floor numbers and direction arrows. * **Information Boards:** Small scrolling text displays. --- ### 5. Interfacing with Microcontrollers When connecting this to an Arduino, ESP32, or STM32: 1. **Current Limiting:** You **must** use resistors (typically 220$\Omega$ to 330$\Omega$) on either the row or column pins to prevent burning out the LEDs. 2. **Drivers:** Because microcontrollers often cannot provide enough current for 7 LEDs at once, transistors (like the PN2222) or dedicated ICs (like the **MAX7219**) are frequently used to drive the matrix.