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A limitation of off-the-shelf perf board is that it is designed for through-hole electronic parts with 0.1-inch spacing. Due to miniaturization, there is a reduced selection of modern components that come in such packages.
Take for example, a simple 3-pin bipolar transistor such as the 2N3904 (or its equivalent). The SOT-23 surface-mount version is difficult to prototype on a perf board. One option is to hack on some wiring:
Soldering wires on surface mount transistors.
I used a plain piece of FR-4 substrate (also called Garolite) as the surface. It’s a cotton, polyester, or glass cloth laminate with epoxy, polyamide, or phenolic resin binding. It’s the same type of material found underneath the copper layer on circuit boards. Therefore, you can simply use a bare spot on a board, or the non-copper side of a single-sided board.
A little bit of DAP silicone adhesive holds the surface-mount component in place. Wires are taped into position and then gently soldered to each lead.
The electronics can be used as is, or they can be removed from the board and inserted into a solderless breadboard or perf board. This technique also works with surface-mount packages with fewer or greater number of pins, such as diodes, capacitors, or ICs. However, groups of really tiny pins are almost impossible to solder this way.
A more professional approach, while still being within the realm of generic prototyping is to use a proto-board specifically designed for surface-mount components.
Surface mount transistor on a 6008 Surfboard.
The above board is laid out to fit SOT-23, SMD 0805, SMD 1206, as well as a variety of other industry standard sizes. Copper traces can be scored and cut out with a razor blade to create other layouts. Additionally, there is a variety of Surfboard-brand boards available for SOIC and more complex multi-pin ICs.
Before leaving the subject of circuit boards, there is one last tip I’d like to recommend. Many hobbyists create devices that have multiple parts or multiple levels. Also, it isn’t uncommon to find yourself working on several different projects at the same time.
The price of low-volume runs of PCBs is most affected by the per-board and per-order (setup and shipping) costs. A hobbyist can minimize costs by incorporating several designs onto a single board and cutting them up yourself. This is called “panelizing”.
Panelizing a PCB by including multiple designs on a single board.
Since the companies want to make money, some PCB manufacturer’s have rules against panelizing. The manufacturers that I use have never complained.
If your PCB manufacturer disallows panelizing PCBs, you can often lay out the board to make it appear to be single item. Dummy traces or power lines could connect the panels together. When you separate the panels, you just cut through and ignore the superfluous copper.
Holes at the intersections can sometimes make it easier to depanelize the board.
If your panels do not extend completely from the top to the bottom of a board, then they can’t be cut out simply by running the board over a table saw or a placing it in a shear.
Placing holes at the corners of the panels makes it easier to cut out these smaller pieces. That doesn’t mean you still won’t accidentally overshoot (red arrow above), but generally they snap off without needing to extend the blade all of the way to the next panel’s border.
Finally, let’s take a look at using alligator clips to hold wires during soldering, and how to prevent the ends of the clips from becoming bent in a helping-hands soldering holder.