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72 DESIGN007 MAGAZINE I NOVEMBER 2019 I know what you're thinking: "He can't pos- sibly write an entire article dedicated to the use of copper in PCBs." I say, "Hold my beer." Copper is the primary metal for standard PCBs, which you can find in pretty much every type of electronic device on the planet. And while standard PCB capabilities depend on what materials are used and how they are constructed, copper is the go-to choice. Copper works very well for the conduction of electrical current in any environment. In fact, it has the highest electrical conductivity rating of all non-pre- cious metals, making it highly effective for per- formance and cost. For a vast majority of PCB designs, copper is the conductor of choice. Copper conducts the signal and power for just about every elec- tronic item in your life. Way to go, copper! You are doing a great job. Keep it up. There are, however, challenges associated with its use. Though incredibly conductive, copper is a relatively soft metal and susceptible to corrosion. Insuf- ficient copper-to-edge clearances can result, potentially causing exposed copper, shorts, or corrosion. Resist can flake off of very nar- row traces. During etching, long slivers can wander around in the bath. These loose can- nons of conductivity can affix themselves to a board, keeping un- wanted copper from being etched away, creating unwanted cir- cuits and failed boards. So, how do you get copper to function in a nice, orderly man- ner the way your de- sign calls for it? First, keep an eye out for po- tential problems dur- ing the design phase. To properly control re- sistance and temper- ature rise, use a PCB trace width calcula- tor to determine how thick and wide trac- es need to be. If your board is large enough, wider traces increase reliability. Skinny trac- es can get hot and re- lease all of your magic A Penny for Your Thoughts on Copper Connect the Dots by Bob Tise, SUNSTONE CIRCUITS