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BC547 NPN Transistor

Transistor

Small-signal NPN transistor in a TO-92 package. Switches relays, buzzers and groups of LEDs that draw more current than an Arduino can supply, or amplifies small signals. Always put a current-limiting resistor (typically 1k-10k) on the base.

Specifications

Type

NPN bipolar transistor (BJT)

Package

TO-92

Pin order

Flat side facing you, left to right: C - B - E

Collector-emitter voltage (VCEO)

45V

Collector current (max.)

100 mA

Current gain (hFE)

110 - 800 (by group)

Power dissipation (max.)

500 mW

Transition frequency

300 MHz

Shop prices

• HatfonIn stock1.04 ₺
• KomponentciIn stock1.40 ₺
• MotorobitIn stock1.52 ₺
• Direnc.netIn stock1.54 ₺
• ElektrovadiIn stock2.71 ₺
• Entegre DünyasıIn stock2.98 ₺
• RobocomboIn stock3.00 ₺
• RobotsepetiIn stock3.05 ₺
• HobiDevreIn stock4.80 ₺
• Robolink MarketIn stock6.00 ₺
• Modül ElektronikIn stock8.34 ₺
• Robo90Out of stock2.48 ₺
• SAMM MarketOut of stock2.98 ₺
• F1 DepoOut of stock6.00 ₺

Prices read from the shops' pages on 22 October 2026. Prices and stock may have changed since; check at the shop before you buy.

Projects with this part

• Arduino-Free Dark-Activated LampBeginner25 minA night light with no Arduino and no code, built from just a 9V battery, a BC547 transistor, an LDR and a potentiometer: when it gets dark the LED lights by itself, and it goes out when the light comes back. With the potentiometer you set how dark it must be. It teaches three cornerstones of basic electronics: the voltage divider (the potentiometer and the LDR), the transistor as a switch that turns a large current on and off with a small base current, and limiting an LED's current with a resistor. You see how these parts, used in Arduino projects all the time, work without one.Open project