### BC856-B-AE3-R: Electronic Component Overview The **BC856-B-AE3-R** is a general-purpose **PNP Epitaxial Silicon Transistor** designed specifically for surface-mount applications. It is the PNP complement to the BC846 series. --- ### 1. Key Technical Specifications The following table summarizes the primary electrical characteristics of the BC856-B-AE3-R: | Parameter | Symbol | Value | Unit | | :--- | :--- | :--- | :--- | | **Collector-Base Voltage** | $V_{CBO}$ | -80 | V | | **Collector-Emitter Voltage** | $V_{CEO}$ | -65 | V | | **Emitter-Base Voltage** | $V_{EBO}$ | -5.0 | V | | **Collector Current (DC)** | $I_C$ | -100 | mA | | **Total Power Dissipation** | $P_{tot}$ | 200 - 250 | mW | | **DC Current Gain** | $h_{FE}$ | 220 – 475 | (Grade B) | | **Transition Frequency** | $f_T$ | 150 (Typ) | MHz | --- ### 2. Breakdown of the Part Number The alphanumeric code provides specific details about the component's construction and packaging: * **BC856**: The base model number (PNP General Purpose Transistor). * **B**: The "Current Gain Selection." In this case, "B" indicates a medium gain range (typically 220 to 475). * **AE3**: Refers to the physical package type, which is **SOT-23**. * **R**: Indicates the packaging method, typically **Tape and Reel**. --- ### 3. Physical Features & Pinout The device is housed in a standard **SOT-23** plastic package. It features three terminals: 1. **Base (B)**: Controls the flow of current between emitter and collector. 2. **Emitter (E)**: The source of charge carriers (holes). 3. **Collector (C)**: Collects the charge carriers. --- ### 4. Common Applications Due to its high voltage rating ($V_{CEO}$ of 65V) and small footprint, it is widely used in: * **Switching Circuits**: Driving small relays, LEDs, or other low-current loads. * **Amplification**: Low-noise pre-amplifiers and signal processing. * **Power Management**: Use in voltage regulation and constant current sources. ---