BC337

The BC337 is a general-purpose NPN bipolar junction transistor in a TO-92 package. It handles up to 800 mA of collector current, much more than the BC547, so it is a popular choice for switching relays, buzzers, LED groups and small DC motors from an Arduino, ESP32 or Raspberry Pi pin, and for audio driver stages.

BC337 Specifications

• Type: NPN bipolar junction transistor (BJT)
• Package: TO-92, through-hole
• Collector-emitter voltage (VCEO): 45 V
• Collector-base voltage (VCBO): 50 V
• Collector current (IC): up to 800 mA
• Power dissipation: 625 mW
• DC current gain (hFE): 100–630, depending on the gain group (-16, -25 or -40)
• Complementary PNP: BC327

BC337 Applications

• Driving 5 V and 12 V relays from microcontroller pins
• Switching buzzers, LED groups and small DC motors
• Audio output and driver stages
• Low-side switches in battery-powered circuits
• Electronics education and STEM labs

What's in the Box

• 1 × BC337 NPN transistor

Tip: With the flat face towards you and the legs down, the BC337 pin order is usually collector, base, emitter (C-B-E). Use a base resistor (about 1 kΩ from a 5 V pin for loads up to roughly 100 mA, lower for heavier loads) and fit a flyback diode such as the 1N4007 across relay and motor coils.

Orders placed before 14:00 are ready for pickup the same day. Delivery across Lebanon usually takes 1–3 working days.