The BC337 transistor is a general-purpose NPN transistor commonly used for switching and amplification in electronic circuits. It is stronger than many small signal transistors and can drive relays, buzzers, and small motors.
1. Basic Description
Type: NPN Bipolar Junction Transistor (BJT)
Package: TO-92
Main Use: Switching and signal amplification
Common in: Arduino, NodeMCU, and sensor circuits
2. Pin Configuration
When the flat side faces you and the legs point downward:
Pin
Name
Function
1
Collector (C)
Connects to load
2
Base (B)
Control pin
3
Emitter (E)
Connected to ground
Order:
C – B – E
3. Electrical Characteristics
Parameter
Value
Collector-Emitter Voltage (Vce)
45V
Collector Current (Ic)
800mA (0.8A)
Power Dissipation
625mW
Gain (hFE)
100 – 630
Frequency
~100 MHz
Because it can handle up to 800mA, it is often used to drive:
Relays
Buzzers
Small DC motors
12V alarms