The **2N3772** is a high-power NPN bipolar junction transistor (BJT) designed primarily for high-current, high-power linear applications. It is well-known for its robustness and ability to handle significant current loads. --- ### 1. Technical Specifications The following table summarizes the key electrical characteristics of the 2N3772 transistor: | Parameter | Symbol | Maximum Rating | | :--- | :--- | :--- | | Collector-Emitter Voltage | $V_{CEO}$ | 60 V | | Collector-Base Voltage | $V_{CBO}$ | 100 V | | Emitter-Base Voltage | $V_{EBO}$ | 7 V | | Continuous Collector Current | $I_C$ | 20 A | | Peak Collector Current | $I_{CM}$ | 30 A | | Total Power Dissipation ($T_C = 25^\circ C$) | $P_D$ | 150 W | | DC Current Gain ($I_C = 10A$) | $h_{FE}$ | 15 to 60 | | Package Type | Case | TO-3 (Metal Can) | --- ### 2. Key Features * **High Power Dissipation:** Capable of dissipating up to 150W, making it suitable for heavy-duty power supplies. * **High Current Handling:** Supports a continuous current of 20A, which is high for a single bipolar transistor. * **TO-3 Metal Package:** The metallic casing ensures excellent thermal conductivity, allowing for efficient heat dissipation when attached to a heat sink. * **Low Saturation Voltage:** Ensures minimal power loss during switching or high-current conduction. --- ### 3. Pinout Configuration The 2N3772 utilizes the standard **TO-3** metal can package. Because it only has two visible pins, the body of the transistor serves as the third terminal. | Pin Number | Terminal Name | Description | | :--- | :--- | :--- | | Pin 1 | **Base** | Controls the biasing of the transistor. | | Pin 2 | **Emitter** | Current exits the transistor through this pin. | | Case | **Collector** | The metal body/flange acts as the collector. | --- ### 4. Typical Applications The 2N3772 is commonly found in older or heavy-duty industrial equipment: 1. **Linear Power Supplies:** Used as a pass transistor for high-current voltage regulation. 2. **Audio Amplifiers:** High-power output stages for PA systems or subwoofers. 3. **DC Motor Control:** Driving large motors where high torque/current is required. 4. **Inverters:** Converting DC battery power into AC power. --- ### 5. Implementation Example To use the 2N3772 in a circuit, you must ensure proper heat sinking. Below is a simplified representation of how to bias it as a switch: ```text Input Signal --- [Resistor] --- Base (Pin 1) Collector (Case) --- [Load] --- VCC Emitter (Pin 2) --- GND ```