BC558 BJT PNP Transistor TO-92

The BC558 is a general‑purpose PNP bipolar junction transistor (BJT) in a compact TO‑92 package. Designed for low‑voltage, low‑power analog and switching tasks, it’s a reliable choice for electronics components projects, from educational builds to professional designs. Ideal for prototyping with microcontroller platforms.

Key Features 🔧

• PNP transistor for controlling current flow in low‑side referenced circuits.
• TO‑92 package for easy breadboarding, through‑hole assembly, and compact layouts.
• Manufactured with quality materials for durability and stable performance.
• Gain‑bandwidth (fT) ≈ 110 MHz for wideband small‑signal applications.
• Optimized for low‑voltage, low‑power operation.

Technical Specifications 📊

• Transistor Type: BJT PNP
• Package: TO‑92
• Collector‑Emitter Voltage (VCEO): −30 V
• Collector‑Base Voltage (VCBO): −30 V
• Emitter‑Base Voltage (VEBO): −5 V
• Collector Current (IC): −100 mA
• Power Dissipation (PD): 500 mW
• Gain‑Bandwidth Product (fT): ~110 MHz

Applications 🔌

Well‑suited to a wide range of analog and digital support roles in electronics:

• Small‑signal amplification stages
• Switching of low‑current loads
• Signal processing and conditioning
• Power management control paths
• Audio amplification preamp and driver stages

Prototyping & Integration 🧪

• Drop‑in friendly for breadboard use and through‑hole PCBs.
• Compatible with common microcontroller I/O for transistor‑based interfaces and drivers.

Design Notes ✅

• Observe polarity: as a PNP device, the emitter is typically at a higher potential than the base/collector.
• Keep within ratings (VCEO −30 V, IC −100 mA, PD 500 mW) and provide adequate thermal management.
• Use appropriate base biasing to ensure saturation in switching applications and linearity in amplifier stages.