PCB Transformers

printed circuit boards

PCB transformer can refer to a transformer that is located on a printed circuit board or a transformer that contains polychlorinated biphenyl. This article covers PCB transformers that are located on a printed circuit board, not those that contain polychlorinated biphenyl.

The transformers utilized on printed circuit boards are necessarily compact, and because of that they don't have the sophisticated cooling mechanisms that are sometimes included with other transformer designs. These transformers will generally come with a rating for the maximum and minimum temperatures at which they can be operated. Provided they are kept within these temperatures, they provide reliable service and, because they are transformers, they can keep providing that service for many decades.

Understanding how printed circuit board transformers work begins by understanding what a printed circuit board is and how it came to be. 

What are Printed Circuit Boards?

printed circuit boardsA printed circuit board is a means of connecting various electric components in a very compact and convenient way. Rather than using standard wiring, a printed circuit board utilizes pathways that are made out of copper sheets, which are laminated onto a surface that is nonconductive. The pathways are etched into the circuit board itself with acid.

Printed circuit boards that have wired devices included on them are properly referred to as a printed wiring board. You will see both printed circuit boards and printed wiring boards used in a variety of different electronic applications. The design of printed circuit board that most people will be familiar with it is located on the inside of computer, which provides all of the various components that the device needs to function in a very compact package that is economical to produce and that offers excellent performance and longevity characteristics.

History of PCBs

While most people likely think of printed circuit boards as modern inventions, work on these devices actually began over 100 years ago. The initial experiments involved early versions of the processes that are still in use today. For instance, in the early 1900s, Thomas Edison was already working on developing linen paper as a sort of printed circuit board. Other inventors were working on the same concept, utilizing a variety of different materials and techniques to attempt to etch a permanent circuit onto a surface.

By World War II, printed circuit boards were already in use. There were utilized in proximity fuses on bombs. As was the case with much of the technology that was developed during World War II, printed circuit boards eventually made it to the consumer market. By the 1950s, there were already consumer devices with printed circuit boards included in them.

The first printed circuit boards that users would of seen had wires on them, with the components sticking through the printed circuit board and oftentimes being connected underneath it via wires. As technology evolved, however, it became more common to see the components on a printed circuit board situated only on the surface. As time has passed, this has become the convention.

Today's printed circuit boards are capable of holding very sophisticated and very powerful electronics in a form that is resistant to shock, that is very long–lasting and that doesn't have many of the weaknesses associated with actual physical wires being installed on a circuit board.

What Materials are Used to Produce PCBs?

To make a printed circuit board, it only requires four surprisingly simple components. Copper foil, copper clad laminate, resin impregnated cloth and non–copper clad laminate are all a user needs to create a printed circuit board.

Even though the components may be simple, the manufacturing process is quite complex. The part of the process that most people will likely be familiar with is etching. Etching works in a very simple way and allows for the mass production of printed circuit boards for very affordable prices.

On a printed circuit board, a material is used to dissolve the copper that is not wanted on the circuit board. All that remain behind are the pathways that were intended to be included on the circuit board. It is also possible for manufacturers to make double–sided circuit boards and other technologies that make the boards more versatile.

The circuit boards that you'll see in electronic devices today represent the current incarnation of this type of technology. Over the years, the way they are constructed has changed many times and, as technology has improved, the complexity of the circuits that are able to be fitted on a printed circuit board has increased tremendously.

Hobbyists can also make printed circuit boards on their own. This can be done utilizing a film or a laser printer, either of which produces the pattern desired for the printed circuit board, which is removed, leaving only the circuit board itself.

What are PCB Transformers??

PCB transformers are transformers that are specifically designed to work on a printed circuit board. They are generally surface mount devices that sits somewhat above the surface of the board, providing whatever voltage transformation or current transformation may be needed.

These devices come in a variety of different capacities and sizes, ensuring that there are enough options for just about any imaginable product. These are also inexpensive parts, making printed circuit boards even more economically viable as ways to produce electronic components.

There is also a type of PCB transformer that doesn't have a core. This allows the transformer to be reduced in size considerably, though these devices are primarily still at the experimental stages. The applications for such devices, however, are tremendous.

Which Applications Use PCB Transformer?

PCB transformers are used in a variety of different applications. In computer hardware, the fact that a transformer can step of voltage down to a safe level makes them indispensable. They are also utilized in a great variety of different manufacturing processes, and in other consumer devices wherever a transformer is needed. A PCB transformer can feasibly save a great deal of money and a great deal of space in the design compared to using a larger transformer.

Who Manufactures PCB Transformers?


Block is a component seller that has been in business for a very long time and, in addition to selling PCB transformers, sells a wide variety of other products.

Halo Electronics

Headquartered in Santa Clara, California, Halo Electronics, Inc. has a large catalog of electrical components, including transformer solutions for a wide variety of different applications.


Hammond Electronics, located in Orlando, Florida, is another popular producer of electronic components, including PCB transformers.

Murata Power Solutions

Catering to customers large and small, Murata Power Solutions has offices located around the world and carries a variety of different electric components.


Myrra is a large electronics component supplier, offering products that are suitable for industrial applications and home wiring applications.


RS has a very large catalog of electronic components, the entirety of which is available on their various websites.


Schaffner specializes in electromagnetic compatibility products and supplies those products to a variety of very large industries.


Stancor provides industrial transformers of many different varieties, supplying largely to industry with a worldwide reach. They are based in St. Louis, Missouri.

What is the Primary Voltage Rating of PCB Transformer?

primary voltage ratingThe primary voltage rating of the PCB transformer is the voltage across the primary winding on the core. It is determined by the number of windings on that core.

What is the Secondary Voltage Rating of PCB Transformer?

The secondary voltage rating of a PCB transformer is the voltage across the secondary core, after it has been transformed. This, as is the case with the voltage on the primary winding, is determined by the amount of turns in the winding.

What is the Power Rating of PCB Transformer?

The power rating of a transformer is a quantification of how much power the device can handle without overloading. In a very high power transformer, coolants such as liquids and forced air are utilized to keep heat to an acceptable level. On printed circuit boards, he levels aren't nearly as high as they would be in a high power transformer, but those heat levels may be absolutely vital to determine whether or not the device that utilizes the printed circuit board is able to function.

What Mounting Types Exist?

Printed circuit boards may be fitted with a transformer in two primary ways: surface mount and through hole. It is also possible to etch a transformer directly onto a printed circuit board, though this obviously doesn't require any mounting at all.

• Surface Mount

surface mounted PCB transformer has no pins or other components that penetrate through the printed circuit board itself. This allows for a more compact design.

Surface mounted components have become the norm for printed circuit boards over the years. Because they facilitate more compact designs, they have generally become the preferred way to affix any type of an electronic component to a printed circuit board. While this was not always the case, taking apart any computer or other electronic device will likely reveal that most of the components on that device have been mounted to the surface of the board and that there are no wires or other items penetrating through.

• Through Hole

through hole mounted transformer on a printed circuit board has connectors that penetrate through the board. This allows for the use of multilayer printed circuit boards and for other applications. Through hole mounting is generally less compact and a more outdated method of mounting components to printed circuit boards than is mounting them directly onto the surface. For some applications and for some particular components, however, it is still the preferred way to mount to a printed circuit board. You'll find that the vast majority of transformer components on printed circuit boards these days are surface mounted, however. On older devices, you may be able to disassemble them and see printed circuit boards with plenty of through hole mounted components.

What is the Number of Outputs of PCB Transformer?

The number of outputs denotes how many transformed voltage outputs are available on the PCB transformer. This is specified in the datasheet for the transformer in question.

What Does the Maximum Operating Frequency of a PCB Transformer Define?

The maximum operating frequency of a PCB transformer – usually measured in hertz – defines the highest frequency that the transformer can operate at with safety and with the desired output parameters.

What Does the Minimum Operating Frequency of a PCB Transformer Define?

On a PCB transformer, there will be a specification for the minimum operating frequency. Running the transformer at a lower frequency may have unpredictable results and may actually damage the component.

What Does the Minimum Temperature of a PCB Transformer Define?

Every electronic component has a minimum operating temperature. On PCB transformers, this number may be relevant because the industrial equipment or other equipment to which the transformer is affixed may be expected to operate at temperatures that are near or below the minimum. Below the minimum operating temperature, the performance of the transformer cannot be guaranteed.

What Does the Maximum Temperature of a PCB Transformer Define?

All transformers produce some level of heat and the maximum temperature of a PCB transformer defines the hottest conditions under which the transformer can be operated. Exceeding this number can cause malfunctions, damage to circuits and other issues. Because printed circuit board transformers don't have the options of liquid cooling or other sophisticated types of cooling, it's important for engineers to keep the maximum operating temperatures in mind.

What Does 3D CAD Model Define Related to PCB Transformer?

A 3–D CAD model of a PCB transformer will define the shape, size, output configuration and other aspects of a transformer so that it can be accurately called for in the design of a given component. Because there are so many different designs on the market, there is a great deal of flexibility in utilizing these components, but 3–D CAD models provide a way to ensure that everything is compatible on a product in terms of the parts being used.3D CAD Model