Construction Using Perf Board  
  I prefer to assemble most prototype and one-off circuits on a perforated board. If I am making several of the same thing, and the circuit has been debugged and refined, I may elect to lay out a board and have it etched at a circuit board fab house.
 
Perf board is generally available in two forms, as shown below. In both cases, the holes are on 0.1 inch centers. This allows the direct placement of most discrete components, integrated circuits, and many types of connectors.
 
No plating   Thru-hole plating
Raw phenolic board. Punched. Nothing to solder to. Inexpensive.   Glass-epoxy board. Drilled. Through-hole plated. Solder components to plating. Expensive.
 
 
  Perf board is available in large sheets, which you cut into appropriate sizes, and is also available in standard sizes with standard edge connectors included. If you are building a board to go into your PC, for example, you would want a board with a 16 bit ISA bus connector already implemented. On the other hand, if you are building a circuit that will go into a plastic project box, you will want to cut a piece from a large sheet to fit inside the box you have selected.
 
Cut the board to size using the following method. Leave sufficient room for standoffs or other mounting hardware. Scribe and then break the board along a row of holes. File the edge of the board until smooth.
 
Raw Edge   Filed Edge
Broken along holes.   Edge filed smooth.
 
 
  Components Bend the leads before inserting the components into the board. Most components fit easily into a 0.1 inch grid of holes. Don't bend component leads too close to the component body!
 
Connect the components together on the bottom side of the board. Use bent leads to connect components that are very near to each other. Use insulated wire to connect components that are more than a few tenths of an inch apart.
 
Use a small soldering iron with a small pointed or chisel tip. I recommend 30 watts or less. I use a 15 watt Antex iron that is very small and light weight. Always keep the tip clean. Wipe off excess solder often, using a damp rag or sponge.
 
Resist the temptation to solder every component to every through-hole. As you debug the circuit, you will often want to change the value of one or two resistors or capacitors. If they are soldered too well, it is really difficult to modify the circuit!
 
Most of the circuit problems you will have can be spotted by a careful visual inspection. Unless your eyes are very sharp, consider using a magnifying work lamp or a hand held glass to inspect closely.
 
Move the work around in the light so that reflections help you see the layers of connections. If you see a questionable connection, or a possible short between connections, perform a second check using an Ohm-meter.
 

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