Perforated Prototyping Board Patterns

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Pre-etched and pre-drilled printed circuit boards offer a generic grid of holes on copper clad substrate. These prototyping boards look similar to solderless breadboards, with rows and columns of holes and buses for holding electronic components. Unlike the solderless variety, perforated PCBs are designed to have the electronic parts soldered to them for more permanent usage.

Pre-etched boards save hobbyists the time and cost of laying out and etching (or ordering) boards with their specific device’s patterns. This makes it easy to design as you build, modify a design, or expand into the remaining space on the board. You can quickly cut out a piece to fit into a project -- rather than having to put the project aside while you etch or buy a specially designed PCB.

Single-Sided with Single Hole per Pad

The simplest pattern that is readily available in perforated boards consists of a large grid of identical holes with a little bit of copper surrounding each hole on one side of the board.

Single-sided single-pad-per-hole perfboard.

Single-sided single-pad-per-hole perfboard.

The picture above shows the copper around the holes on one side of the board, but plain holes on the opposite side of the board. I’ve used such boards on numerous projects, even for entire robots such as Bugdozer.

It wasn’t until recently that I decided that this board pattern is incredibly lame.

The problem with having only one hole per pad (area of copper) is that you need to stuff multiple wires into each hole to connect anything together. I suppose that’s acceptable if all you’re doing is point-to-point wiring or wire wrapping. However, it is a pain to desolder a wire without the other wires in the same hole coming loose. And, you often end up with too many wires to fit in a single hole for things like positive voltage and ground.

There are much better choices nowadays.

Single-Sided with Multiple Holes per Pad

Using boards with multiple holes per pad is a major improvement for most projects. That is, groups of holes are connected to each other by copper traces. These are called “terminal strips” or “busses”. In most cases, you only need to solder one wire per hole, with additional wires soldered to the adjoining holes connected by the copper traces.

Perf board with 3-hole islands, buses, and corner patterns.

Perf board with 3-hole islands, buses, and corner patterns.

Even better, power and ground can be connected to the longer traces (called “buses”) for convenient distribution throughout the board. For example, the board pictured above features a long T-shaped bus. If needed, you can make precision cuts to the copper in the middle of a bus to break the busses into smaller segments.

Double-Sided Plated-Through with Multiple Holes per Pad and Busses

Now we reach the most modern of the through-hole prototyping breadboards. Like the previous board, the board contains a large grid of pre-drilled holes with connecting copper trace patterns that form buses and terminal strips.

However, these boards are superior in that they have:

PB10 double-sided plated-through patterned perf board by Wright Hobbies.

PB10 double-sided plated-through patterned perf board by Wright Hobbies.

There is an EMC (electromagnetic compatibility) article by Microchip that encourages parallel power busses underneath the IC chips. Parallel power busses actually benefit from board capacitance. It’s like getting a bunch of tiny built-in capacitors. Designs like Eddy Wright’s (above) also make it convenient to place a real 0.1 µF capacitor directly beside the power pins of the chip. 

Because these premium prototyping boards have copper on both sides, you can insert and solder components on both sides of the board. There have been numerous occasions when I’ve wanted a connector on one side and components and wires on the other side. On single-sided board, I’m stuck with snaking wires through the holes and back to the side with copper.

Make sure that the boards are not simply “double-sided”! You want “double-sided with plated-through holes”. The plating connects the pads on the top side to the bottom side. If the board is only double-sided, you may mistakenly think you’ve wired one part to another simply because you’re using the same trace grouping (even though they are on opposite sides).

Without plated through holes, you'll need to insert a bare wire and solder it on both sides to connect the two trace groups together. Or, you can solder the lead of a component on both sides of the board.

By using double-sided plated-through proto boards with trace and bus patterns you can easily connect common components on either side of the board with minimal wiring. They aren’t even that expensive if you select the right supplier. You can pick up a nearly 500-hole board from Wright Hobbies for a little under $4 (part #PB10).

Alternatively, the next time you have a little leftover space on a PCB that you’re having manufactured, you should consider making yourself a little perfboard.

Miniature perf board in leftover space.

Miniature perf board in leftover space. Perfect for an 8-pin DIP chip.

Mini boards created this way are much more expensive per inch than from a production retailer. However, if that space was just going to go to waste, then it is basically free. (Note: Some PCB production houses limit the number of holes they will drill per board or refuse to allow multiple projects per board.)