BC558 PNP General Purpose Transistor – TO-92 Package for Switching & Amplification

Reliable Low-Power Switching and Amplification

The BC558 is a versatile PNP bipolar junction transistor (BJT) that serves as the perfect counterpart to the NPN BC548.
It is widely used in electronic circuits for its ability to handle low power and low noise, making it ideal for signal processing and small-scale
switching applications.

Whether you are building a simple LED flasher, an audio pre-amplifier, or an Arduino-controlled switch for small loads, the BC558
provides stable performance in a compact TO-92 package. Its high gain and low saturation voltage ensure efficient
operation even in battery-powered projects.

Key Features:

• PNP Complement: The direct PNP version of the popular BC548/BC547 NPN transistors.
• Low Noise: Engineered for high-fidelity signal amplification with minimal distortion.
• Standard Package: TO-92 plastic casing is easy to handle and fits perfectly into breadboards and PCBs.
• High Gain: DC current gain (hFE) ranges from 110 to 800, allowing for sensitive signal triggering.

Technical Specifications:

• Transistor Type: PNP
• Package Type: TO-92
• Collector-Emitter Voltage (Vce): -30V
• Collector-Base Voltage (Vcb): -30V
• Emitter-Base Voltage (Veb): -5V
• Continuous Collector Current (Ic): -100mA
• Power Dissipation (Pc): 500mW
• Operating Temperature: -65°C to +150°C

Common Applications:

• Low-power switching circuits (driving LEDs, Relays, or Buzzers).
• Audio frequency (AF) amplifiers and pre-amps.
• Signal processing and logic gate construction.
• Darlington pair configurations for increased current gain.

Maker Tip: Remember that as a PNP transistor, the BC558 turns “ON” when the base is pulled Low (connected to Ground) and “OFF” when the base is High (connected to VCC). Always use a base resistor (e.g., 1kΩ to 10kΩ) to protect the transistor from excessive current.