Perfboard

I was looking at some photos and realizing how much perfboard I have used in recent years. I routinely find myself building small circuits, and that process almost always begins with grabbing a bit of perfboard from the supply stash.

Perfboard is the basis of point-to-point wiring and has been around since well before I started in electronics as a young teenager. It is generally a small circuit board with holes drilled in a 0.1″ grid.

The holes are usually about 0.042″ and will accommodate a wide range of electronic components without modification. Cheap perfboard will have no copper pads or traces, good perfboard will have a pattern of copper traces and pads to which you can solder your components. Better yet is perfboard with plated-thru holes and pads on both sides.

Using perfboard is easy, just thread the component leads through the holes, bend the leads over, and solder the connections. Many components feature 0.1″ spacing of the leads and naturally slip into the board.

I use enough that I keep a fair selection of perf on-hand. When buying a pile of stuff at the recent Radio Shack closing sale I bought a stack of perfboards. The boards can be a bit expensive, but at 80% off I grabbed all I could, at least of the sizes and types I like to use.

I like pad-per-hole perfboard. You can get busses, lines, or solid planes. Pad-per-hole is completely free-form, you can arrange your circuit any way you want with no restrictions. You can also get pad-per-hole with a solid copper plane between the holes, this can be used to provide a good ground plane and is quite useful in analog or other noise sensitive circuits.

Layout out a circuit on perfboard is a bit of an artform. How to arrange and group your components to make connections easy and to provide a very functional circuit takes a good amount of forethought. A well arranged circuit minimises the number of wire jumpers you must use, making the connections with only the component leads.

With the advent of surface mount circuitry I found myself worrying that there would be a day when perfboard construction would be a thing of the past. Now, after decades of surface mount domination of the industry I find perfboards are still a very viable way to build one-off circuits.

A lot of through-hole leaded components remain available, and many surface mount parts can be soldered directly to perf. The common 0805 and 1206 surface mount resistors and capacitors solder neatly between holes, SOT-23 and DPACK transistors also solder to the 0.1″ spaced pads. It is only the high lead count IC’s that are a real issue, for those you need a breakout board. Indeed, there are a wide range of breakout boards available for many interesting and useful IC’s.

Despite fears of it’s demise, I will probably be building circuits on perfboard as long as I live. Yes, there is another circuit I need to construct this week, most likely a GenPIC PCB for control along with a bit of perfboard for some relays.