PCB Assembly Services - Screaming Circuits: The right tool for the job


The right tool for the job

I once ordered a set of surface mount resisters and instead received a bag of 5.5mm barrel jacks. Funny thing is, the label and part number on the bag were correct for the SMT part. The part that I received is common and has been around for a long time. It's used as the power connector for the Arduino and a host of other DC or low voltage AC devices. It is also one of the components that often makes for awkwardness during layout and Fab.

Barrel jack

The most popular variety comes with lugs designed for point-to-point wiring, not PCB mount. That's the legacy of decades of popularity.

The lugs require a slotted cutout in the PCB. However, the common practice, again stemming from years back, is to use large plated holes instead of the slots. This technique did reduce PCB costs back when slots were a very expensive addition. However, solderability and mechanical strength will be greatly increased by either using a PCB mount part, with pins instead of lugs, or using slots in the design of your CAD footprint.

Some designers (myself included) have used overlapping vias as a hack to create an almost slot. That can lead to broken drills in the fab shop or a poor fit on the finished PC board.

It's always best to use the proper tool or technique. Read a few more PCB layout tips over at Sunstone Circuits in their Tech Drill Down.

Once you have that PCB ready to go, we can order from Sunstone for you and assemble them into your prototypes and production boards. Visit www.screamingcircuits.com to get a quote and place your order. 

Duane Benson
But how do you reverse a neutral polarity?



I still use plated holes for those power sockets. I first encountered that part over 20 years ago. It hasn't changed.

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