Bipolar Junction Transistor (BJT)
makerA BJT is a type of semiconductor device that amplifies or switches electrical currents using three layers of differently doped semiconductor material.
expanded
A Bipolar Junction Transistor (BJT) is a current-controlled device consisting of three alternating layers of p-type and n-type semiconductor material configured as either npn or pnp. BJTs are widely used for amplification in audio circuits, switching in digital electronics, and in sensor circuits due to their ability to handle high currents and operate efficiently at high frequencies.
examples
2N2222 is an example of an npn BJT capable of switching currents of up to 800 mA.
Commonly used in amateur and professional maker projects for switching applications due to its reliable performance and widespread availability.
BC547 is a general-purpose npn BJT with a collector current of up to 100 mA and a voltage rating of 45 V.
Typically used in small-signal amplification tasks such as audio pre-amplifiers and RF circuits.