This brief list is just the tip of the iceberg, and you will most definitely become familiar with many more as you progress into more complex designs.
Annular Ring
The ring of copper that is located around a plated through hole in a PCB. This ring is usually what you will heat up with your soldering iron when hand soldering in a component. It provides a larger surface area for the solder to “grab” onto.
BOM (Bill of Materials)
A comprehensive list of all components and materials required to assemble a PCB, including part numbers, quantities, and sourcing information.
Copper Pour
The process of filling unused PCB areas with a copper plane to improve grounding, reduce interference, and enhance heat dissipation.
Component Placement
The process of arranging electronic components on a PCB to optimize functionality, minimize interference, and ensure efficient manufacturing.
DIP (Dual In-line Package)
A common package type for integrated circuits (ICs) with two parallel rows of pins that can be inserted into holes in the PCB.
Drill Hit
These are defined as the places on a design where a hole should be drilled or where they actually were drilled on the board. In instances of inaccuracies, the drilled hole can be off by a few tenths of a millimeter or more due to dull drill bits.
DRC - Design Rule Check
A software check of your design to make sure it does not contain errors such as traces that incorrectly touch, traces too skinny, or drill holes that are too small. This digital inspection is often governed by the manufacturer who will be creating your PCBs for you.
ERC - Electrical Rule Check
Generally run at the end of the design phase, this automated check will make sure your design follows the basic rules of electronics. If an error is detected, such as a “short circuit," VCC and GND together, it will give you a warning and highlight the bad connection on the schematic.
ESD (Electrostatic Discharge)
The sudden flow of electricity between two objects caused by a static charge imbalance. ESD protection is crucial for sensitive electronic components.
ESR (Equivalent Series Resistance)
The internal resistance of a capacitor, an important parameter in selecting capacitors for specific applications.
Fab House - Fabrication House
Short for Fabrication House. This term is often used when talking about the manufacturing facility that will be producing your PCBs.
Finger
These are exposed copper pads along the edge of a board which are used to create a connection between two circuit boards. A very common example of fingers are found on the edges of computer expansion cards such as video cards, or on the connector on cartridge-based video games.
Footprints
A footprint is most commonly used to refer to the pad shape and size in direct relation to the component of which it represents. Ensuring that the footprint used in the PCB design matches the component it represents is critical in creating a successful PCB.
Gerber File
The Gerber format is an open ASCII vector format for 2D binary images. It is the de facto standard used by industry software to describe the printed circuit board images: copper layers, soldermask, legend, etc. Gerber is used in PCB fabrication data.
GND - Ground
This refers to the ground signal. It is the reference at 0 volts. Therefore, all other voltages in the circuit are relative to GND.
HASL - Hot Air Solder Leveling
A method of coating exposed copper with solder by inserting a panel into a bath of molten solder then passing the panel rapidly past jets of hot air.
IPC Standards
A set of industry standards published by the IPC (Association Connecting Electronics Industries) that define requirements for PCB design, manufacturing, and assembly.
JTAG (Joint Test Action Group)
A standardized method for testing and programming integrated circuits on a PCB, commonly used for debugging and boundary scanning.
Mouse Bites
This is an alternative method to a term we will cover a little later down this list called v-scoring. Mouse Bites are used for separating boards from panels quickly and are the result of a number of drill hits that are positioned so that they are almost touching, but leave a very thin, and thus weak spot between separate boards. This allows the boards to be broken easily after they have been manufactured.
Net
This is a virtual representation of a wire. It is used to virtually connect each lead of a component to another part of the schematic.
Pad
A pad is a portion of exposed copper on the surface of a PCB to which a component is soldered. Pads can feature through holes, but are often square or rectangular in shape. Pads are most common on footprints for integrated circuits, or SMD components.
Panel
This is defined as a larger circuit board composed of many smaller boards which will be broken apart before use. Automated circuit board handling equipment frequently has trouble with smaller boards, and by aggregating several boards together at once, the process can be sped up significantly. “Panelizing” several board designs into a single board is also a way to cut down on the cost of manufacturing, but check with your manufacturer first to see if this is allowed at their facility. Some of the small run manufacturing facilities will panelize several customer’s designs together in order to reduce their cost, and to make things easier for their equipment to process.
Paste Stencil
For PCBs that utilize surface mount parts, a thin, metal (or sometimes Mylar or plastic) stencil is created from the CAD files which features small holes in the shape of the pad’s that the components will be soldered to. This allows the manufacturing facility or the customer to easily and quickly apply solder paste to the pads of the PCB. This makes placing the SMD components by mechanical methods or by hand much easier, and ensures a consistent application of solder to each component and pad.
Pick-and-Place Machine
If you are having your PCBs populated after they have been manufactured, then a Pick-and-Place machine will be used to populate the components to the board before being soldered in a reflow oven. This automated process ensures that the correct component is placed in proper orientation to the PCB, which helps to reduce errors that are sometimes found when populating an SMD board by hand.
Pin
This is a connection point in an IC or component. Typically ICs have as little as 3 pins to as many as 128 pins or more. Often in your designs, you will add net connections to these pins, but all of the pins are not always utilized by your circuit.
Plane
This is a continuous block of copper on a circuit board and is usually defined by borders rather than by a path. This is sometimes also known as a “pour,” and can be used to save time in the etching process as it means that there is less copper to remove from the substrate. Often times, you will see tutorials that use a copper pour as a ground plane, which will help to reduce the number of traces on a board. Planes can also be used as heat sinks, RF, and EM shielding as well.
PTH - Plated Through-Hole
The Plated Through-Hole is a design component that you are very familiar with if you have ever soldered a through-hole component such as a resistor, diode, LED, etc, onto a PCB. These holes often feature an annular ring and the holes are plated through from one side to another and can be used as vias if needed.
Reflow
When soldering SMD components to a PCB, a process called reflowing is used. In its simplest form, the PCB is placed in an oven which is then heated to the melting point of the solder paste that was applied to the board earlier. This process has become highly refined over the years, and temperature profiles have been created for various solder paste compositions to ensure that the solder properly flows around components and anneals as it cools to prevent cracking or so-called “cold solder joints.”
Silkscreen
As its name implies, the letters, numbers, symbols, and imagery on a circuit board are usually applied with a silk-screening technique. This layer is almost always applied on top of the solder mask layer. While it is possible to find a PCB manufacturer that offers different colors of silk-screening, the industry standard color is white.
Slot
A slot is defined as any hole in a PCB which is not a round hole. Slots may or may not be plated, but they almost always feature round ends due to the router bits that are used to cut them. Slots sometimes add cost to the board because they require extra cut-out time or have extra plating requirements.
Solder Paste
As its name implies, solder paste is a spreadable material made up of a matrix of small balls of solder that are suspended in a gel medium made from flux. Solder paste is generally applied with a stencil but can be applied with a syringe or small brush. Solder paste is almost always applied to surface mount pads on a PCB before the components are placed by a Pick-and-Place machine. During the reflow process, the solder in the paste melts along with the flux, creating clean electrical and mechanical joints between the pads and the components.
Solder Mask
This is a layer of protective polymer material that is applied over the etched copper surface of a PCB and is designed to prevent short circuits, corrosion, and other problems. Its most useful feature is its ability to resist molten solder from sticking to it, creating a method to easily prevent solder bridges between traces in the soldering process. This layer is sometimes referred to as the “resist” layer and is most famous for its forest green color. Many manufacturers now offer solder masking in several different colors.
Surface Mount (SMD - Surface Mount Device)
This is a form of components that are designed to be placed on top of the PCB for soldering which does not require a through hole for a component’s legs to fit through. Also called SMD, this form factor has allowed components to be shrunken in size by several orders of magnitude, thus allowing more component-dense designs. This is the dominant method of assembly in use today and allows boards to be populated quickly and easily via automated processes.
Trace
This is the heart and soul of a PCB. A trace is a continuous path of copper on a circuit board, that has been isolated from the rest of the copper by either chemically etching or mechanical removal of the copper layer around it. Traces are used to connect components together to form circuits. Traces can vary in width and thickness based on the current load they are designed to handle.
VCC/Vin:
This refers to the input voltage from an external source. The input voltage can be obtained from external sources such as mains power outlets, wall transformers, batteries, dedicated power supplies, or even solar panels. In general, anything that can supply power to the circuit. VCC is relative to GND.
V-score:
Much like the mouse bites we covered earlier, a V-Score is a partial cut through a board, allowing the board to be easily snapped along a line. A V-Score is created with a V-shaped router bit.
Via: Similar to a plated through hole, a via is a hole in a PCB that is used to pass a signal from one layer to another. When a via is covered with solder mask, it is considered a tented via and is designed to protect layer-to-layer signal transmission from errant solder bridges.
Wave Soldering
This is the precursor to reflowing and is often used when a PCB is populated with through-hole components, although SMD components can be wave soldered if they are glued to the PCB. This process gets its name from the PCB being passed over a standing wave of molten solder. The PCB height is adjusted so that the components' leads and the bottom of the PCB barely touch the solder wave.
