## Technical Overview of the 2SD814-R Transistor The **2SD814-R** is a Silicon NPN epitaxial planar type transistor specifically designed for low-frequency power amplification and driver stage applications. It is commonly found in audio equipment and power management circuits. --- ### 1. General Specifications The "R" suffix typically denotes the **hFE (DC current gain) ranking**, which identifies the specific gain range of the component. | Parameter | Symbol | Value | Unit | | :--- | :--- | :--- | :--- | | **Type** | - | NPN | - | | **Collector-Base Voltage** | $V_{CBO}$ | 100 | V | | **Collector-Emitter Voltage** | $V_{CEO}$ | 80 | V | | **Emitter-Base Voltage** | $V_{EBO}$ | 5 | V | | **Collector Current (DC)** | $I_C$ | 1 | A | | **Collector Power Dissipation** | $P_C$ | 1.2 | W | | **Junction Temperature** | $T_j$ | 150 | °C | --- ### 2. Gain Classification (hFE) The 2SD814 is categorized into ranks based on its current gain. The **R** rank is defined as follows: | Rank | hFE Range | | :--- | :--- | | **Q** | 120 to 270 | | **R (This model)** | **180 to 390** | | **S** | 270 to 560 | --- ### 3. Pinout Configuration The 2SD814 is usually housed in a **TO-92L** (long) or **TO-126** package, depending on the manufacturer (commonly Panasonic/Matsushita). The standard pinout is: 1. **Emitter (E)**: Connects to the ground or negative side of the load. 2. **Collector (C)**: Connects to the load. 3. **Base (B)**: The control terminal (input). --- ### 4. Key Features and Applications * **High Voltage:** With a $V_{CEO}$ of 80V, it is suitable for circuits with higher voltage rails than standard small-signal transistors. * **Linearity:** It offers excellent linearity of DC current gain ($h_{FE}$), making it ideal for high-fidelity audio reproduction. * **Driver Stage:** Frequently used as a driver for high-power output transistors. #### Common Uses: * Audio frequency power amplifiers. * Voltage regulators and switching circuits. * Relay and motor drivers. --- ### 5. Equivalent/Replacement Parts If you cannot find a 2SD814-R, the following transistors are often used as substitutes (ensure you check pinout compatibility): * **2SD1207** * **2SD667** * **KSC2690** (High-performance alternative)