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PCB Basics

Editorial Team - PCB Directory

Jan 15, 2020

HASL (Hot Air Solder Leveling) is a metallic surface finishing technique, which is performed on the outermost layer of the PCB board to protect the exposed copper surfaces like tracks until the component placement and soldering is completed.The HASL coating is composed of Solder with 63% Tin and 37% Lead, and during the assembly process, this coating gets dissolved with the soldering material.The ...read more

What are PCB Gold Fingers?

PCB Basics

Editorial Team - PCB Directory

Jan 15, 2020

Gold Fingers are the gold plated narrow connectors found on the edge of printed circuit boards to enable connections between multiple boards. They are made from flesh gold, the hardest form of gold available and work for a long time with superior conductivity. The thickness of gold fingers usually ranges from 3 to 50 microns.Gold is chosen for these fingers as it has the highest corrosion resistan...read more

What are Fiducial Marks on a PCB?

PCB Basics

Editorial Team - PCB Directory

Jan 15, 2020

Fiducial marks are recognition marks, created in the form of small pads on the PCB board to act as reference points for PCB Stencil alignment and for automated component placement by Pick and Place machines. During the PCB Assembly process these points are used by automated machines to ensure correct positioning of the board. These points are also measurable and act as a frame of reference during ...read more

What is PCB V-Scoring?

PCB Basics

Editorial Team - PCB Directory

Jan 15, 2020

PCB V-Scoring is a process of cutting a ‘V’ shaped groove at the top and bottom of a printed circuit board leaving a thin layer between the Vees. Once this is done, the PCB Board can easily be separated at the V by applying minimal pressure.A single PCB board can be divided in to multiple sections by V-Scoring. This is must useful during the PCB assembly process, as all sections of the...read more

Polyester PCB Boards

PCB Substrates

Editorial Team - PCB Directory

Sep 15, 2019

Polyesters, also called Polyethylene Terephthalate (PET), are the most commonly used material to manufacture flexible PCBs. They are best-known for their flexibility, good electrical properties, and high chemical and moisture resistance.Key Characteristics:They have a melting point of 250ºC and a glass transition temperature of 80ºC.They have lower heat resistance that inhibits their use...read more

What are Copper Based PCBs?

PCB Substrates

Editorial Team - PCB Directory

Sep 14, 2019

Copper-based PCBs use copper as a primary base material in place of commonly used FR4. The copper base material is then covered with an insulating layer followed by a circuit layer. Copper core/based PCBs are known to have excellent heat dissipation and can be used for high frequency applications with minimal variation in performance over wide temperature ranges. However, these advantages do come ...read more

What are Aluminum-based PCB boards?

PCB Substrates

Editorial Team - PCB Directory

Sep 14, 2019

Aluminum-based Printed Circuit Boards use an Aluminum alloy as a base material for the PCB i.e. the dielectric layer is sandwiched between the Aluminum alloy and circuit layer. The Aluminum alloy is a composite of magnesium and silumin (Al-Mg-Si).Aluminum based PCBs are part of the Metal Core PCB family and deliver excellent thermal conductivity and insulation.Key Advantages of Aluminum Based PCBs...read more

What is Glass Transition Temperature (Tg)?

PCB Basics

Editorial Team - PCB Directory

Jul 13, 2019

Tg or the glass transition temperature is the temperature at which the base material of a PCB starts to transform from a brittle/rigid form factor to a soft, elastic one. The Tg value of a printed circuit board usually depends on the substrate used. This is one of the factors that you must consider when selecting the substrate materials for your PCB. You should make sure that the temperature where...read more

What is Loss Tangent?

PCB Basics

Editorial Team - PCB Directory

Jul 13, 2019

In PCBs, Loss tangent (tan (δ)) is the measure of signal loss due to the inherent dissipation of electromagnetic energy in the substrate of the printed circuit board. It is a dimensionless quantity and generally referred to: Loss Factor, Tan δ, Dissipation factor and Loss angle.All PCB materials have both conduction losses and dielectric losses. The conduction losses are resistive and ...read more

What are Composite Epoxy Materials (CEMs)?

PCB Substrates

Editorial Team - PCB Directory

Jul 12, 2019

Composite epoxy materials (CEMs) are made by combining two or more materials having different chemical and physical properties to achieve the desired substrate material with unique properties and characteristics. Epoxy synthetic resin is used to combine materials. It acts as a binding agent to hold the materials together. It also transfers the thermal stress between the materials and protects them...read more

What is Copper Weight in a PCB?

PCB Basics

Editorial Team - PCB Directory

Jul 12, 2019

Copper is one of the most important elements in PCB boards. Copper Weight or Copper Thickness in a Printed Circuit Board represents the thickness of 1 ounce of copper rolled out over an area of 1 square foot. For example, a PCB that has a copper weight of 1 oz will have a layer of copper that is 1.4 mils in thickness. Copper Weight is measured in ounces per square foot (oz/ft²).Copper Weight ...read more

What are Halogen Free PCB Boards?

PCB Basics

Editorial Team - PCB Directory

Jun 22, 2019

A Printed Circuit Board devoid of the halogen elements is called Halogen free PCB. Halogen elements are Chlorine, Bromine, fluorine, iodine, and Astatine which are very fatal to life. For a PCB to be considered “Halogen-Free” it must have less than 900 ppm of chlorine or bromine and a total of less than 1500 ppm of Halogen materials.In context to PCB manufacturing, the concerned haloge...read more

What is the Solder Mask?

Editorial Team - PCB Directory

Jul 12, 2019

Solder mask or solder resist is a coating applied to a Printed Circuit Board (PCB) to protect the copper traces on the board and to stop electrical shorts. The solder mask is usually applied on both sides of the PCB i.e Top and Bottom to ensure reliability and performance.The solder mask is a Liquid UV Photo-imageable Ink which is usually green in color. Other color options like red, blue, yellow,...read more

What is the Silkscreen in a PCB?

Editorial Team - PCB Directory

Jun 22, 2019

The Silkscreen is the topmost layer of a Printed Circuit Board (PCB) which is used as a reference indicator for placing components on a PCB Board. It requires a specifically formulated ink whose standard color is white, but it can also be Red, Black, Yellow, Blue and a number of other colors.The silkscreen is used to specify useful information on the PCB board that can help/assist users during ass...read more

What is an Annular Ring?

Editorial Team - PCB Directory

May 18, 2019

A via is created by drilling a hole through a copper pad etched on each layer of a PCB. An Annular Ring is the area between the edge of the drilled via and the copper pad associated with that hole. The greater the width of an annular ring, the greater the copper connection around the drilled via will be.In a multilayer PCB, traces are routed from one layer to another layer with the help of vias. T...read more

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