Inside the Tech: How PCBs Power and Connect Every Electronic Device
If you’ve ever taken apart an AirPod, you’d see a small green board inside – the printed circuit board, or PCB. Despite its tiny size, this piece of technology is fundamental to every electronic device. It’s fascinating how a multitude of microscopic components connect and communicate via such a compact PCB. And as amazing as its functionality is, the material value is noteworthy, too – for instance, you can extract about 0.3 grams of gold from the PCBs found in a laptop. Here, we’ll explore the design and manufacturing process of PCBs.
The PCB Manufacturing Process
To kick off the process, we first design the PCB using EasyEDA, a free software that can generate a 3D view of the design. Once the design is ready, the next step is to print it using a plotted printer on a plastic sheet with a photo-negative image of the circuit in black ink.
The design is then transferred to a copper plate with a photoresist layer, exposed under UV light. This hardens the areas where light passes through the clear parts of the printout. The black ink blocks the light, preventing these areas from hardening. After exposure, the non-hardened copper areas are removed with chemicals, leaving behind the designed circuit.
Following fabrication, the PCB is protected with a solder mask and goes through an optical inspection. Then it’s ready for component mounting. JLCPCB showcases this process, where components are carefully placed on the PCB in a factory setting.
Reducing PCB Size for Compact Devices
For devices like AirPods, space is crucial. But simply shrinking the PCB isn’t straightforward – reducing the distance between traces can lead to electrical issues, and reducing trace thickness affects current capacity. The solution is often a double-sided PCB, which places some traces and components on both sides.
However, even double-sided PCBs face challenges like interference, where traces placed too close to each other generate magnetic fields that impact nearby traces. Additionally, two metal traces close together can act like a capacitor, causing voltage changes. For high-frequency signals, this can be a major problem, so multi-layer PCBs are used to separate ground and power layers with insulating layers in between. PCBs today can have up to 12 layers or more, each layer connected with electrical vias created by mechanical drills or lasers.
Heat Management and Gold Plating
Another crucial function of a PCB is heat management. Vias act as heat sinks, transferring heat from components to the outside. Some PCBs even contain a small amount of gold – a metal chosen for its conductivity and resistance to oxidation and corrosion. Due to its cost, gold is only used as plating on connectors, such as where an SSD or graphic card connects to a laptop motherboard.
Extracting Gold from a PCB
For those interested in extracting gold, it’s possible, albeit a lengthy process. Submerging a PCB in nitric acid for a week dissolves the copper and plastic, leaving the gold. The remaining solution is then filtered, and the gold flakes are heated into a solid chunk.
Designing a PCB with EasyEDA
EasyEDA makes PCB design simple. You can create a schematic for a circuit, like a Bluetooth headset, and convert it to a PCB design. This software arranges components within the PCB outline, showing copper areas in red and non-copper areas in black. Once the design is complete, you can send it directly to JLCPCB for fabrication, which ensures a reliable, cost-effective product with fast delivery.
Hope you enjoy exploring the journey of PCBs with us! We hope this deep dive into PCB design and manufacturing has been insightful.
Frequently Asked Questions
1. What is a PCB and why is it important?
A PCB (Printed Circuit Board) is the backbone of any electronic device, connecting various components and allowing them to communicate. It enables the compact and efficient functioning of electronic circuits.
2. Can I extract gold from my old electronics?
Yes, certain electronics, especially high-value devices like laptops, contain small amounts of gold. However, the extraction process involves chemical handling and is generally not cost-effective for small quantities.
3. Why do some PCBs have multiple layers?
Multi-layer PCBs help reduce electrical interference by separating power and ground layers. They are especially useful for high-frequency devices, where interference can be a significant issue.
4. How can I design a PCB?
You can use free software like EasyEDA to design a PCB. This tool allows you to create schematics and convert them into PCB layouts, which can then be sent directly to manufacturers like JLCPCB for production.
