BC547 NPN Transistor – 45V 100mA TO-92 for Switching & Amplification
BC547 Transistor
The BC547 is an NPN bipolar junction transistor in a compact TO-92 package. It handles up to 100mA of collector current and 45V across collector-emitter, making it a versatile choice for low-power switching and small-signal amplification in embedded and hobbyist circuits.
Key Specifications
| Specification | Value |
|---|---|
| Transistor Type | NPN BJT |
| Max Collector-Emitter Voltage (Vce) | 45V DC |
| Max Collector Current (Ic) | 100 mA |
| DC Current Gain (hFE) | 110 to 800 (group‑dependent) |
| Package | TO-92 |
| Pinout (flat face) | Collector, Base, Emitter (left to right) |
What You Can Build With This
- Arduino-based LED flasher or dimmer using PWM
- Simple audio preamplifier for a microphone module
- Relay or small DC motor driver with flyback protection
- Touch‑activated switch or rain sensor circuit
Compatibility
The BC547 works with any microcontroller platform that provides base drive voltage above 0.7 V, including Arduino (5 V logic) and Raspberry Pi (3.3 V logic with appropriate base resistor). It pairs easily with other common TO-92 transistors like the BC557 (PNP complement) and with signal diodes, resistors, and small relays.
Wiring Notes
Always use a base resistor (1 kΩ typical for 5 V logic) to limit base current. Connect the emitter directly to ground, place the load between collector and the positive supply, and ensure the collector current stays below 100 mA to avoid permanent damage.
Why Buy from Compoden
Every component is sourced from verified suppliers and tested for compatibility before listing. We've spent 10 years building projects for makers, schools, and institutions across India. Ships from Bengaluru in 3-5 days. If defective on arrival, replace within 7 days.
Is this compatible with Arduino?
Yes. Connect a 1 kΩ resistor between the Arduino digital pin and the base, ground the emitter, and place your load (like an LED with its own resistor) between the collector and 5 V.
How do I identify the pins?
Hold the transistor with the flat face toward you and the pins pointing down. The pins are, from left to right: Collector (C), Base (B), Emitter (E).
Can I use it to drive a relay directly?
Yes, as long as the relay coil current is under 100 mA. Place a flyback diode across the coil to protect the transistor from voltage spikes when switching off.
📦 Free Setup Handoff Document Included
Every Compoden order includes a free setup handoff document — step-by-step instructions to get your component working within minutes. Download it via QR code on your package. The handoff document is also trained to help you troubleshoot the majority of problems.
Ask Soldr above what you can build with this — it knows every Compoden kit this part appears in.
Shipping Information
- Prepaid Orders: ₹75 for orders up to ₹999, FREE shipping above ₹999
- COD Orders: ₹125 shipping + ₹50 COD fee = ₹175 total
- Delivery Timeline: Dispatch in 1-2 days, delivery in 2-7 days depending on location
Returns & Warranty
- 7-Day Return: Manufacturing defects only (approval required)
- Warranty: 7 days from delivery
- Non-Returnable: Batteries, consumables, cut wires, clearance items