The 2N3904 is a classic NPN silicon transistor, designed for low-power signal amplification and switching applications. It is renowned for its versatility, low cost, and excellent performance in a wide range of applications, from simple LED circuits to complex digital systems.

Technical Specifications (Specs):

• Type: NPN Silicon Epitaxial Planar Transistor
• Package: TO-92 (Plastic)
• Maximum Collector-Emitter Voltage: 40V
• Maximum Collector Current: 200mA (Continuous)
• Current Gain: 100 to 300 (for typical current values)
• Transition Frequency: 300 MHz (Suitable for low-frequency RF applications as well)
• Complementary PNP: 2N3906

Main Applications:

• Switch: Driving small loads such as LEDs, buzzers, and small relays
• Signal Amplification: Pre-amplification of audio and sensors
• Digital Circuits: Used in logic gates and timers (e.g., with IC 555)
• PWM Control: Controlling brightness or speed of small motors