The **2SC4774-AL3-R** is an NPN epitaxial planar silicon transistor designed primarily for low-frequency amplification and high-speed switching applications. It is frequently used in signal processing and power management circuits due to its stable gain characteristics and compact footprint. --- ### 1. General Specifications The following table outlines the key electrical and physical characteristics of the 2SC4774-AL3-R: | Parameter | Symbol | Maximum Rating | Unit | | :--- | :--- | :--- | :--- | | **Collector-Base Voltage** | $V_{CBO}$ | 60 | V | | **Collector-Emitter Voltage** | $V_{CEO}$ | 50 | V | | **Emitter-Base Voltage** | $V_{EBO}$ | 7 | V | | **Collector Current (DC)** | $I_C$ | 100 | mA | | **Power Dissipation** | $P_D$ | 150 | mW | | **Junction Temperature** | $T_j$ | 150 | °C | | **Storage Temperature** | $T_{stg}$ | -55 to +150 | °C | --- ### 2. Key Features * **High DC Current Gain ($h_{FE}$):** Provides excellent linearity across a wide range of collector currents. * **Low Saturation Voltage:** $V_{CE(sat)}$ is typically low, ensuring minimal power loss when the transistor is in a fully "on" state. * **Compact Packaging:** Typically housed in a small-outline package (such as SOT-23 or SOT-523, depending on the specific manufacturer suffix), making it suitable for high-density PCB designs. * **High Reliability:** Built using epitaxial planar technology for consistent performance and thermal stability. --- ### 3. Pin Configuration The device usually follows the standard 3-pin surface mount configuration: 1. **Base (B):** Controls the current flow between the collector and emitter. 2. **Emitter (E):** The lead through which the current leaves the transistor. 3. **Collector (C):** The lead through which the current enters the transistor. --- ### 4. Typical Applications The 2SC4774 series is versatile and found in various electronic segments: * **Switching:** Used as a digital switch to control small loads (LEDs, relays). * **Amplification:** Low-noise pre-amplification for audio or sensor signals. * **Regulation:** Part of voltage regulation circuits in portable consumer electronics. --- ### 5. Identification (Part Number Breakdown) * **2SC:** Indicates a Japanese (JIS) standard NPN high-frequency transistor. * **4774:** The specific model number identifying its electrical curve. * **AL3:** Often refers to the specific gain classification (hFE rank) or packaging variant. * **R:** Generally indicates the packaging type (e.g., Tape and Reel).