Canadian Manufacturing

Key factors to consider when manufacturers are deciding between NPN and PNP transistors

NPN has far more superior functions than PNP. However, PNP is extensively used and recommended in the United States.

December 8, 2021  by Alfie Frenilla, Content Manager

PHOTO: Manufacturing/Nick Youngson via

Manufacturing companies, particularly those that mass-produce electronic circuits, work pretty much around bipolar junction transistors, like PNP and NPN. However, choosing between these two BJTs can be a huge conundrum for a developing company, especially a neophyte engineer working solo for his startup.

If you’ve used sensors before and have gained a little understanding about them, you would know that PNP is activated by a low signal, whereas a high signal starts NPN. As we know, the P indicates the polarity of the emitter terminal, and the N represents the polarity of the base terminal in a PNP transistor.

There are several essential aspects to consider while picking between NPN and PNP. But first, you need to understand the fundamental distinction between NPN and PNP amplifiers. The current flow from collector to emitter in the NPN transistor when the positive supply is applied to the base is vital variations between the NPN vs PNP.

In reality, NPN transistors are more commonly utilized in electrical circuits than PNP transistors. NPN transistors have several significant and beneficial benefits, so they are widely used in ac conductors. However, let’s take a look at what you’ll need to consider while deciding between NPN and PNP.


Electron Mobility

Electron mobility is a characteristic that describes how rapidly an electron may move across a semiconductor when an electric field pushes it. The leading charge carrier in a PNP transistor is a hole, whereas electrons are the majority carrier in an NPN transistor. Electrons have higher or quicker mobility than holes. Hence their conductivity is more elevated. As a result, NPN transistors are advantageous to PNP transistors because they give conductivity.

Negative Ground

We know that all negative (-ve) or standard terminals in electrical circuits are grounded. The +ve lines in a PNP transistor become a common point for input and output that cannot be dropped. NPN transistor, the -ve lines create a single topic for both input and output, grounded. As a result, they are utilizing an NPN transistor rather than a PNP transistor aids in grounding the negative terminal.


When switching transistors happen in electrical circuits, the NPN transistor is preferred over the PNP transistor because the NPN transistor has a faster switching speed than the PNP transistor.

Manufacturing Facility and Reliability

NPN transistors are less expensive to produce than PNP transistors because PNP needs nearly three times the silicon chip surface area of NPN. Moreover, The NPN transistor is more reliable than the PNP transistor due to its incredible speed, smaller size, lower cost.


Because of electron mobility, NPN transistors are better suited for tiny amplifier circuits that employ BJTs. The frequency response of an NPN transistor is superior to that of a PNP transistor.

Common Emitter Configuration

A typical emitter setup is the most often used amplification configuration. Because the -ve line forms a common point for both input and output signals in a standard emitter arrangement, the NPN transistor is suitable for the usual emitter configuration. But then, when the PNP transistor is utilized in a standard emitter configuration, the +ve line becomes a single point for both input and output signals that cannot be grounded.

As we accumulate these facts, we can observe that NPN has far more superior functions than PNP. However, for some reason, PNP is extensively used and recommended in the United States. This should help you decide between NPN and PNP.