In this article, we are going to explain the transistor BC550 pinout, features, datasheet alternate, compliment, and other detail. Transistor BC550 is a general-purpose BJT transistor of the BC547 series. The transistors in this series are commonly used for wide-purpose applications in commercial devices and also in academic and hobby electronic projects.

BC550 Pinout and Diagram Configuration

Pin Number

Pin Name




Electrons Emitted from Emitter Collected by the Collector



Controls the biasing of the transistor



Electrons emitted from the emitter into the first PN junction

BC550 Transistor Pinout features and other detail

Characteristics of BC550 transistor

  • Type - NPN
  • Package - TO-92
  • Max Collector-Emitter Voltage: 45 V
  • Max Collector-Base Voltage: 50 V
  • Emitter-Base Voltage Max: 5 V
  • MaxCollector Current: 0.1 A
  • MaxCollector Dissipation - 0.5 W
  • DC Current Gain (hfe) - 110 to 800
  • frequency of transistor - 150 MHz
  • Noise Figure - 1.2 dB
  • Maximum and Minimum Operating and Storage Junction Temperature Range from -65 to +150 °C

BC550 Transistor Equivalent Transistor

The equivalent or alternate of BC550 are BC547, BC548, BC549, C945, 2S5200, C828, 2N2222 and many other. The pin configuration of the alternate transistors may different so, please must check the technical specification and pinout before using any alternate BC550 transistor.

Basic Working of a Transistor

BC550 is a general purpose an NPN transistor, in NPN transistor electrons work as the primary charge carriers that flow from the emitter of the transistor. When a positive voltage is applied to the base of the transistor the holes are created to the base of the transistor.

Complement of BC550 Transistor

The complement transistor of BC550 Transistors is BC556, BC557, and BC558.

SMD Equivalent

SMD Equivalent of the BC550 are available as the BC847 (SOT-23), BC847W(SOT-323), BC850 (SOT-23).

Applications of BC550 Transistor

  • Preamplifier for Power Amplifier
  • LED dimmers or flashers
  • Switching relates and LEds
  • PWM driven application
  • Switching Applications

Datasheet of BC550

datasheet of bc550 transistor

2D Model and Dimensions

The 2D model and dimensions of BC550 are given below in the diagram

2D Model and Dimensions