BC857 transistor belong to PNP general purpose transistors. General purpose switching and amplification are the main applications of  this transistor.

Specifications:-

• Mounting Style: SMD/SMT 
• Package/Case: SOT-23-3 
• Transistor Polarity: PNP 
• Configuration: Single 
• Collector- Emitter Voltage VCEO Max: 45 V 
• Collector- Base Voltage VCBO: 50 V 
• Emitter- Base Voltage VEBO: 5 V 
• Maximum DC Collector Current: 0.2 A 
• Gain Bandwidth Product fT: 100 MHz 
• Maximum Operating Temperature: + 150 C 
• DC Current Gain hFE Max: 125 at 2 mA at 5 V  
• DC Collector/Base Gain hFE Min: 125  
• Minimum Operating Temperature: - 65 C  
• Pd - Power Dissipation: 250 mW