Nuts and Volts - December 2008

■ PHOTO 6. The four-position diskette drive power connector is something we’ve been plugging into for years. You can get this power connector and its mating plug from Jameco. The center power receptacle is actually a Type-B USB connector. The business end of a wall wart power cable mates nicely with the industry standard 2.5 mm male power jack.

which of the diskette drive power interface pins you connect, you’ll get + 12 VDC or + 5 VDC. So, be careful. Believe it or not, the Type-B USB connector is 0.1 inch friendly. Two of the USB connector’s four pins — which sit on 0.1 inch centers — carry + 5 VDC (pin 1) and ground (pin 4). I had to break out the Moto-Tool to mount the 2.5 mm male power jack. This power jack allows you to power your breadboard from the wall wart of your choice.

How I Do It

There’s a breadboard behind every PCB I present in my Nuts & Volts and SERVO Magazine articles. Needless to say, I’ve done my share of breadboarding. I use 30 AWG Kynar wirewrap wire to make my breadboard signal connections. The Kynar insulation is easily deformed by the direct heat of a hot soldering iron. Thus, it is possible to accidentally overheat it and compromise the wire’s insulation by creating a void. It’s uncanny, but those insulation voids always seem to create shorts to nearby exposed connections on my breadboards. If things on your breadboard are squirrely and you can’t find a logical reason why, check for wires that are stuck together or stuck to a neighboring solder connection. The insulation voids usually occur at those points.

If the breadboard requires a power and ground bus, I complete the component layout and then route the power and ground busses on the breadboard copper using 22 or 24 AWG tinned copper bus bar.

Working smart also includes being smart when it

comes to tool selection. I consistently use the following breadboarding tools:

• PanaVise Electronic Work Center with 315 Circuit Board Holder

• Variable Speed Dremel Moto-Tool

• Metcal MX-5005 Soldering/Rework System

• Crescent Hand Tools (Home Depot)

Over the years, I’ve developed breadboarding methods and habits that work well for me. As time passes and you do more and more breadboarding, you will benefit from your experiences, as well.

By the way, if you’re having trouble finding that FR- 4 plated through-hole breadboard I’ve been talking about in the catalogs, stop looking. I’ve supplied a downloadable ExpressPCB file that will allow you to make one (or a few) of your own ( www.nutsvolts.com). See you later ... I’ve got some breadboarding I have to do. NV