What are primary and secondary sides of PCB?

I am designing a 2 layer PCB with components on both side of it. SMT components are one one side of PCB, but TH (through hole) components are on both sides. I need to understanding something mentioned by the supplier called primary and secondary sides.

November 23, 2023

The primary side is the side that has most of the components, especially the ICs. The most common soldering technique these days is reflow soldering. It is simply easier to get precision temperature profiles on one side of the board only.

The secondary side can also support components, but

it’s harder to control the temperature precisely, and
gravity works against you as the solder paste begins to melt and the components on the underside of the board want to fall off.

Oliver Smith

Oliver is an experienced electronics engineer skilled in PCB design, analog circuits, embedded systems, and prototyping. His deep knowledge spans schematic capture, firmware coding, simulation, layout, testing, and troubleshooting. Oliver excels at taking projects from concept to mass production using his electrical design talents and mechanical aptitude.

Oliver Smith

What Others Are Asking

When should I choose 2 layer PCB or 4 layer PCB?

Our brand was focused on common electronic product with single PCB. And this year, we plan to develop a smart range which may require multiple layer PCB. Want to know more about 2 layer PCB or 4 layer PCB.

Oliver Smith September 25, 2023

Can PCB test points be a source of noise?

If I want to design a PCB with as much noise immunity as possible, should I leave off test points? Can PCB test points be a source of noise?

Oliver Smith November 6, 2023

Are SMT components bad for high voltage applications?

Many assembly factories are asking for SMT jobs, while I think through hole would be a better option for a high voltage application. Before the high voltage project is started, we need to make a call on SMT or Through hole parts. Is there a study on this?

Oliver Smith November 22, 2023

What are primary and secondary sides of PCB?

Oliver Smith

Oliver Smith

What Others Are Asking

When should I choose 2 layer PCB or 4 layer PCB?

Can PCB test points be a source of noise?

Are SMT components bad for high voltage applications?

Read Detailed Advice From Blog Articles