Single-Sided PCB Design: Combining Simplicity with Sophistication

PCB (Printed Circuit Board) is a crucial electronic component, acting as both the support for electronic components and the carrier for electrical connections between them. Since the invention of the printed circuit board in 1925, PCB design has become increasingly precise, multilayered, and complex. However, the simplest single-sided PCB remains widely used in industrial products such as radios, washing machines, and remote controls.

1. Structure of a Single-Sided PCB

A traditional FR4 single-sided PCB can only have circuitry on one side, with solder mask on one side and silkscreen (character markings) on both sides (depending on customer design). Since single-sided PCBs do not use the copper plating process, the hole walls are copper-free (Note: Take JLCPCB as an examplein ,based on JLCPCB board material, board thicknesses of 0.4mm, 0.6mm, 0.8mm, and 2.0mm default to double-sided PCB numbering, and the finished product will have copper inside the holes).

2. Soldering on a Single-Sided PCB

Since a single-sided PCB only has circuitry on one side, soldering must be done on the exposed pads on the same side as the circuitry. Depending on the structure of the components, there are two different soldering methods:

1.Same-Side Soldering

The main body of the component and the circuit are on the same side, mostly used for SMT components.

2.Opposite-Side Soldering

The component body is placed on one side, while the circuit is on the other. This method is typical for through-hole or plug-in components.

3. Engineering Design File of Single-Sided PCBs

In practice, PCB design is layered.  

For example, in double-sided PCB design, the top layer design is a direct view, meaning the text appears upright, and the finished board will also show the text upright. For the bottom layer design, it is viewed in reverse (through a mirror effect). If the text is upright in the design of the bottom layer, the actual finished board will show the text in reverse when viewed (because the finished board is viewed from the opposite side).

The same principle applies to circuit layers. Returning to the single-sided PCB, if the design is on the bottom layer, it is viewed in reverse, and the actual board must be viewed through the reverse effect to match the design (as shown in the image).

4. Manufacturing Characteristics in Factories

During actual production, to avoid burrs and peaks, the bottom layer’s wiring is mirrored onto the top layer for production (this mirroring does not affect the original structural design). The advantage of this method is that the drill bit first penetrates the copper surface, and since the baseboard is at the bottom, it ensures the copper surface is drilled cleanly. If the copper surface were drilled from below, it would create many burrs and peaks.

5. Special Notes

Aluminum Base Layer: For single-sided aluminum PCBs, the aluminum base is conductive, so soldering components directly to it can cause a short circuit.

Character Printing: For aluminum-based PCBs, it’s recommended to print characters on the copper side rather than the aluminum side, as they are easier to see on the copper surface.

Despite their simplicity, single-sided PCBs require careful consideration of circuit and soldering placement to avoid design errors. Proper layering and manufacturing processes ensure these boards continue to provide reliable performance for a wide range of industrial applications.