Parts of a Printed Circuit Board Assembly

The “A” in PCBA

Printed Circuit Board Assemblies (PCBAs) are electronic assemblies responsible for connecting the electrical components of a system or device. Their applications range from everyday staples such as smartphones to complex custom box build assemblies. The difference between a PCB and PCBA is the A – Assembly of components to the board. Thinking about a PCB layer as a floor, the PCBA represents the completed building – all stairways and connections built to create a fully functioning operation.

What Are the Components of a PCBA?

PCBAs are flat, thin substrates covered in conductive metal and circuit components. Copper lines, called traces, allow electricity to flow into different board components. In turn, the solder mask insulates the copper traces from other metal parts that might accidentally touch them. Some traces remain exposed so manufacturers can solder components to them.

The following is a closer look at a few of these PCBA components:

Resistors regulate the electric current passing through them and indicate their resistance level through color-coding. Resistors are essential because they can guard fragile components against voltage spikes within the circuit. Additionally, if an element needs a lower voltage than the rest of the circuit, a resistor can drop the voltage to the required level.

Transistors are semiconductor devices that can control or amplify currents. Small currents applied to one of the transistor’s three terminals control these functions.

Capacitors can store electricity and release it when a different component in the circuit needs more power. If there is any fluctuation in the circuit’s exact voltage, capacitors can store excess charge and release it as required.

Inductors store energy in the form of a magnetic field. Since they have power separate from the circuit’s current, they provide current to the circuit even when the switch is off.

Transformers transfer current from one circuit to another using wire coils. Running electricity through the wire coils from one circuit produces a magnetic field that reaches the other circuit’s wire coils. The magnetic field creates a current in the new circuit’s wire coils. We can control the amount of current generated by changing the number of turns of the coils in each circuit.

Diodes / LEDs are elements that only transmit current in one direction and block current in the other direction. In most cases, diodes usually have coloring to note the end that allows flow and the one that does not. They protect fragile electronic components from receiving current from the wrong direction. LEDs, or light-emitting diodes, are a particular type of diode that emits light.

Sensors can detect a change in the environment around the board and translate that into electrical charge. For example, a light sensor can see when it’s getting dark and send current to another element in the circuit, like an LED.

Switches can only be open or closed. If the switch is open, then it allows the current to flow. The switch blocks the current from flowing through the circuit if it is off. This component enables more control of the operator.

How Do Manufacturers Attach Components to a Circuit Board?

At present, Electronic Manufacturing Service (EMS) Providers can attach these components to a printed circuit board through various forms of manual and automated assembly. Even more, two of the most popular are surface mounting and through-hole mounting.

• Surface-mount technology (SMT) is the master of all domains in PCB technology. In detail, it refrains from using drilled holes to attach PCBA components; all components are placed directly onto the circuit board. Assembling circuit boards using SMT automation is the simplest and cheapest method, and it allows full utilization of both sides of the PCB.

• Thru-hole mounting is the old reliable mainstay for secure builds. Pre-drilled holes connect components to the board. Since they are soldered in place, the components can withstand more stress. These boards cost more to manufacture and are more difficult to modify than surface-mounted PCBAs, so this method is better suited for mounting connectors and large components that need extra attention. In large part, this assembly method is behind the times, remaining useful for unique builds. 

PGF Technology’s High-Quality Printed Circuit Board Assembly

If you need expert printed circuit board assembly, PGF Technology can help. We pride ourselves on producing high-quality, cost-effective printed circuit board assemblies. Our experienced manufacturers can walk you through all the different options to find your project’s best components and assembly for your project. Contact us today or request a quote if you’re ready to get started!