NPN transistors are a type of bipolar junction transistor, or BJT. BJTs themselves form a versatile subcategory of the broader discrete semiconductor market, popular in PCB/prototyping work and included in many everyday devices, toys, appliances and gadgets.

BJTs are solid state, three-pin components that can either be bought as PNP (positive-negative-positive) or NPN transistors (negative-positive-negative). We stock a very extensive catalogue of NPN transistors for all manner of electrical engineering and circuit building applications.

What do NPN transistors do, and which should I choose?

• Broadly and simplistically speaking, NPN transistors are three-terminal, three-layer components that can perform various functions within a powered circuit, but are principally chosen to work either as signal amplifiers or as electronic switches
• NPN transistors are basically designed to perform the task of passing electrons along from the emitter pin to the collector pin, in order for the conventional current to be allowed to flow in the opposite (i.e. standard) direction
• The exact type of NPN transistor for your individual project needs will depend entirely on what it is you're trying to achieve with your circuit build
• However, some key parameters you'll likely need to consider when selecting the appropriate NPN transistor for specific electrical engineering designs and applications might include:
• Package type
• Mounting type
• Min/max DC collector current and current gain
• Min/max collector and emitter base voltages
• Maximum power dissipation
• Maximum operating frequency
• Transistor configuration
• Pin Count
• Dimensions
• Min/max operating temperature