BC817-25,215 NPN General Purpose Transistor (45V, 500mA, SOT-23)

Every electronics maker needs a reliable workhorse for switching external components, and the BC817-25 NPN bipolar junction transistor (BJT) is exactly that. When your microcontroller’s GPIO pins (like those on an Arduino, ESP32, or STM32) cannot output enough current to drive a relay, a buzzer, or a high-power LED, this tiny transistor acts as the perfect bridge. Capable of handling a continuous collector current of up to 500mA, it packs a serious punch for its microscopic size, easily driving small DC motors or lighting arrays.

With a high collector-emitter voltage rating of 45V, it is completely safe to use in 12V and 24V systems, making it highly versatile for custom 3D printer boards, automotive DIY projects, and drone auxiliary circuits. Housed in the industry-standard SOT-23 surface-mount package (denoted by the ",215" tape and reel suffix), it requires virtually no PCB space. Whether you are shifting logic levels or building custom driver circuits, the BC817 is an essential, highly reliable building block for any professional or hobbyist hardware design.

Key Features:

• High Current Capacity: Can safely switch up to 500mA of continuous current, which is more than enough for relays, buzzers, and small DC motors.

• Wide Voltage Tolerance: A 45V breakdown voltage allows you to easily switch 12V or 24V loads using a simple 3.3V or 5V logic signal.

• Microcontroller Friendly: Easily driven into saturation by modern low-voltage processors with a minimal base current.

• Space-Saving SOT-23: The tiny SMD footprint saves crucial board space on densely populated PCBs and custom maker projects.

Specifications:

• Part Number: BC817-25,215

• Transistor Type: NPN Bipolar Junction Transistor (BJT)

• Max Collector-Emitter Voltage (Vceo): 45V

• Max Collector Current (Ic): 500mA

• DC Current Gain (hFE): 160 to 400 (Band 25)

• Package Type: SOT-23 (SMD/SMT)