AX Control, Inc.

Circuit Board Reference Designators: FAQs

Circuit board reference designators help identify individual parts on a printed circuit board. — Circuit board reference designators help identify mounted parts on this GE Mark VI PCB. The board has a number of resistors (R), capacitors (C), and integrated circuits (U).

What do you know about circuit board reference designators?

If you’ve worked with printed circuit boards (PCBs) at all, you’ve noticed the letter codes on their surface. These are called reference designators. If you’ve designed circuit boards, you’ve probably spent more time than you want thinking about them.

What are Reference Designators?

Circuit board letters can be confusing when you first start working with components. These small codes litter the board’s surface and are sometimes hard to read. And sometimes they don’t make sense. Q for transistor? U for integrated circuit? What the heck.

Dry Contact: What is it? (Dry vs. Wet)

Twelve dry contact relays populate this GE Mark VI IS200DRLYH1A circuit board. — The MKVI IS200DRLYH1A board has 12 Form-C dry contact output relays.

If you’ve wired control devices, you’ve likely come across the term “dry contact” as well as the reverse, “wet contact.”

But what do those terms mean? More importantly, why would anyone want wet wiring? That doesn’t sound like a good idea at all, does it?

Electricity and water don’t mix. Don’t try it.

What Is a Cartesian Robot?

A Cartesian robot like this 3D printer uses an X, Y, and Z plane. Photo from Unsplash.

We’ve written about robots and robotics before, but we thought we’d go into further detail about different kinds, starting with the Cartesian robot. But before we get there, we probably need to talk about Cartesian systems first. Even before that, let’s talk about where the term “Cartesian” comes from.

Cartesian: what does it mean?

The term “Cartesian” refers to anything relating to French philosopher René Descartes. And no, it’s not because someone thought Descartesian would be too difficult. In fact, the term is based upon his Latinized name Cartesius.