Facts About the BC337 Transistor

A BC337 Transistor

A BC337 Transistor


We shall talk about a unique PCB part called BC337 Transistor in this article.

We discuss the functions of this component, and the several varieties it comes in, as well as provide you with real-world examples.

Why is it necessary for you to understand this component?

We believe that despite appearing insignificant and small, it is crucial to the construction of circuit boards.

To avoid confusion and ensure that everything is understood by the time you reach the end of the article, we will use straightforward language to explain the key ideas.

Explain What is a BC337 Transistor

Explain What is a BC337 Transistor

Explain What is a BC337 Transistor

This is a component of a circuit board. it is made of three pieces of silicon material and has a negative-positive-negative arrangement. These arrangements are explained below:

N – negative collector

P – positive base

N – negative emitter

Due to its three components, it is known as a bipolar junction transistor or BJT.

The two “joints” constituting a junction are the two components sandwiching the base (see “P” above).

This semiconductor device is rated for 50V and a maximum of 800mA.

An alternative for BC337 is the 2N2222 resistor.

What are Transistors Used For

What are Transistors Used For?

What are Transistors Used For?

After defining what is, we move on to the following sub-topic: what are these transistors used for? Why do you need to understand them?

All PCB transistors including the BC337 are utilized for:

Supply current – this refers to the current the component pin carries using the collector pin. For the BC33, anything under 800mA is acceptable.

  • Amplify current – if there is an electronic signal, but it is weak, a transistor makes it “heard” by sort of multiplying the signal, this is what is meant by amplification. A transistor like the BC337 is a low-power amplifier, specifically.
  • Act as a switch – instances where the flow of the electrons need to be disrupted call for a switch. It can only be either “on” or “off”. The BC337 is best used in general switching functions.
  • During instances of sinking current.

Why Specifically Use a BC337 Transistor?

There are specific reasons for using this kind of transistor. To understand why you must know the difference between BJTs and FETs. As well, you should differentiate what a BJT type is compared to an IGBT transistor.

We summarize them below for you:

BJT Transistor vs FET Transistor

FET stands for Field-Effect Transistor. Like the BJT, it can also be used for amplification purposes.

There are other significant differences, namely:

  • The charge is carried by either (1) electrons or (2) holes in BJTs like the BC337. Comparing BJT to the FET Transistor’s design, BJT is bipolar, and FET is unipolar.
  • A FET can give high input for impedance, in this case, it performs better than the bipolar for example, in MOSFETs, the impedance is 1010-1015 Ω.
  • PCBs that need to control currents will use a BJT because a BJT is a current-controlled PCB component.

BJT Transistor vs IGBT Transistor

IGBT stands for Insulated-Gate Transistor.  Like the BJT, it is bipolar in design. However, it bears the following differences when compared to the BJT:

  • IGBTs are better for switches because they have a high switching frequency.
  • Because of their suitability for high-voltage applications, IGBTs are preferred over BJTs for military applications.
  • Electric vehicles use IGBT more than BJTs.
  • IGBTs are more efficient in terms of the amount of space they occupy. They are smaller than BJTs.
  • You can put fewer BJTs inside a microchip since the BJT is bigger than a typical IGBT.

In order for you to master the use of different kinds of transistors, you can watch several helpful tutorials. These will help you to know if the PCB design or electronic design you have is a good fit with the BC337 you have in mind.

One of the best ones we recommend is this video:


You can calculate based on the information provided how many transistors you need for the device you are creating. If you need more help with these kinds of DIY projects, then you can contact us.

Kinds of PCBs with BC337 Transistors

PCBs that have microcontrollers will have BC337 transistors included inside.

There are certain types of PCBs belonging to this category, including the following:

Computer PCB

These PCBs come in a wide range. Typically, are the most familiar kinds:

Audio PCB

  • Amplifier Audio PCB – these are made to boost input signals. The other function is to regulate volume. This transistor can help manipulate the stages/drives of audio frequency. The top layer of the PCB is where the transistors are located, where the amplifier is constructed.
  • Single-phase power supply Audio PCB – Its single phase has adequate power to run any interface. It is preferred because of its low-noise quality. There are filters and regulators built into every piece.
  • Dual channel (2.0) Audio PCB – this enables a stereo mode in audio devices
  • A Buffered Audio PCB – this is catered to high-impedance speakers. It limits the current of the power supply to accommodate differential input stages in the device.

PCBs with IC Substrates

The silicon wafer is referred to as an IC substrate. The transistors are located inside. One of the transistors that can fit inside the IC substrate is the BC337 Transistor. Here are several IC substrate types where the BC337 component can be found.

  • BGA IC –It is frequently present and necessary for all models of high-performance laptops and desktops.
  • CSP IC –The primary benefit of this Chip-Scale Package is that it is smaller than a BGA. The CSP can be either rigid or flexible.
  • FC IC – This is a Flip Chip Package. Its main advantage is particularly for I/O: you can pack more of it in the chip’s space
  • Fine Pitch IC – These types of ICs populate HDI PCBs. A surface mount is used to attach these components to a PCB
  • MCM IC – These ICs are also used in HDI PCBs, but there are other applications as well such as Radio Frequency, LED PCBs, and wearable gadgets for consumers
  • PTH IC – Instead of surface mount, these ICs use Plated Through Hole technology, which takes up more space. The chief advantage is that these are mechanically sturdier.
  • SMT IC – Are Surface Mount ICs. (To know the difference between SMT and THT, you can check our blog here.)
  • Ultra-Thin Core IC – A variation of the thin core IC, this type has the tiniest transistors. Currently, IBM holds the record in making the smallest transistors that can fit here.

BC337 Applications

BC337 Applications

What are the BC337 Applications?

The following are the primary applications for this component:

  • Audio amplification, belonging to the lower power range – is preferred because there are fewer errors used when this type of BJT is used
  • Current control
  • General switching purposes – it is preferred because it is fast-acting as a switch, so it’s no wonder it is used as push buttons
  • LED lighting relays
  • Microcontrollers and microprocessors
  • Physically manipulated switches or buttons to turn devices on and off
  • Some Radio Frequency devices

Choose the Best Manufacturer for PCBs with BC337 Transistor

Choose the Best Manufacturer for PCBs with BC337 Transistor

Choose the Best Manufacturer for PCBs with BC337 Transistor

If you need a BC337 Transistor, you can buy it in any major, well-stocked electronics shop. They are commonplace.

This is a safe bet if you are making circuit boards yourself from scratch.

But if you want to have circuit boards assembled with the components in place (and inside it, the BC337 is already built-in), then you need a PCB manufacturer.

Most people want to save time and money, so they look for manufacturers that comply with all of their demands.

Other considerations include:

  • How much experience does the PCB fabricator have with the semiconductor industry
  • They are effectively used as capacitors, PCB fuses, and PCB switches, in addition to resistors.
  • Their equipment is modern and has precision control.
  • They can modify PCBA services in line with device specifications.
  • Options enable them to work with High-TG materials.
  • Their customer service is excellent and gets great reviews.

At PCBMay, we accept HDI PCBs and specialized designs all with the BC337 Transistor involved.

For you, we can create multilayer HDI PCBs from 2 to 40 layers.

Trust us for all of your PCB projects. We won’t disappoint you.


We talked about the significance of transistors of the BC337 type in the context of printed circuit boards.

It is known that these parts are located inside ICs (integrated Circuits).

They are essential components of microprocessors and a part of a motherboard (the CPU).

These resistors have been established to amplify the current so that the proper amount is supplied to the device.

A smartphone contains thousands of just these parts.

As a PCBA service provider, we at PCBMay make sure that each one of these tiny components does its job so that your device is error-free.

Please contact us if you need any PCBA orders.

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