construction of pcb circuit board
The pcb circuit board is the backbone of any electronic project, and there are many different materials that can be used in its construction. For the most part, PCBs are constructed of a rigid or flexible insulating substrate that has one or more conductive layers laminated to it.
The substrate is often a rigid insulating material like fiberglass or epoxy. This material allows the boards to withstand more abuse during use, especially when the board is being bent and stretched. A rigid insulating substrate can also help to avoid any potential electrical shorting that might occur between different sections of the circuit board.
On the top of the substrate is a layer of copper, which is the conductive portion of the pcb circuit board. The thickness of this copper can vary, and is usually specified in ounces per square foot (or, as we like to say at SparkFun, 1.4 thousandths of an inch). For most PCBs, this translates to about one ounce of copper for every three feet of the length of the circuit board. Some PCBs need thicker copper, such as those that handle high current or need to dissipate a lot of heat.
What materials are commonly used in the construction of pcb circuit board?
Between the copper and the substrate is a non-conductive layer called solder mask. This layer gives the circuit boards their green color, and it acts as an insulator between the copper traces and other components on the board. It is also helpful to keep solder from sticking to places where it shouldn’t, which can cause shorts or even a fire.
After the conductive layer is applied to the substrate, a pattern is imaged on it using a photoresist material. The exposed areas are then etched away, leaving behind the copper traces on the circuit board. This process is known as chemical etching, and it is a critical step in the production of a quality pcb.
Once the conductive layer has been etched, it is covered with a layer of solder mask. The solder mask is what gives the circuit board its green color, although it can be colored in a number of other ways. It is important to have good solder mask to insulate the copper traces and prevent them from shorting with other parts of the circuit board.
A common component on a pcb is a resistor. These are vital to any electronics circuit, as they help to control the flow of electricity through it. The pcb will also have capacitors which store energy, much like small batteries. Finally, the pcb will have transistors which act as switches to change the flow of electricity between components.
A fuse is also commonly found on a pcb, and is the best way to protect against current overloading. It is the only component on a pcb that can be replaced after it has been blown, which makes it very important for the safety of the user and anyone else who may be touching the circuit board.
