BC557 PNP Transistor

The BC557 is a bi-polar general-purpose PNP transistor widely used across switching and amplifying applications in analog and digital circuits. Unlike an NPN transistor, current flows out of its base to turn it on: the connection between collector and emitter stays closed until a base voltage is applied, at which point the connection opens and the load is switched off, making it especially handy for high-side switching circuits.

Housed in the compact, easy-to-solder TO-92 package, the BC557 is a staple component for hobbyist and professional circuits alike, from simple relay and LED driver stages to more involved audio and signal amplifier designs. Its well-documented characteristics and low cost make it a reliable first choice whenever a PNP switching or amplifying transistor is called for.

• Type – PNP
• Continuous Collector Current – 100mA
• Collector-Emitter Voltage – 50V
• Base Trigger Voltage – 6V
• Base Current – 5mA
• Current Gain – 300 (max)
• Package – TO-92
• Common Uses – Relay drivers, LED drivers, audio/signal amplifiers, Darlington pairs

Reliable and versatile, the BC557 PNP Transistor belongs in every well-stocked electronics component drawer.