2N3643 classic NPN silicon transistor (NOS gold pin)

The 2N3643 is a classic NPN silicon transistor known for its reliable performance in amplification and switching applications. With a maximum collector-emitter voltage of 30 V and collector current rating up to 500 mA, it suits medium-power circuits. Its total power dissipation of 350 mW allows it to handle moderate energy loads, and it comes in the TO-105 or TO-92 package, making it compatible with many vintage and hobbyist electronic designs. Although now obsolete, it remains valuable for restoring or studying legacy equipment.