What is a circuit board?

A circuit board is a printed circuit board (PCB, Printed Circuit Board) that is used to implement the function of a specific electronic circuit. It is a substrate with a pattern of electrically conductive lines that are connected through materials such as metal connectors or conductive inks. Circuit boards are key components in electronic devices, responsible for connecting individual electronic components together so that they can work together.

The design and manufacture of circuit boards is an important part of the production of electronic products. On a circuit board there are soldering points for various electronic components that are connected through the circuit board's wiring to form specific electrical signal paths. These paths can be different types of wiring such as power, ground, signal lines, etc. to perform specific electronic functions.

The process of manufacturing circuit boards includes the following major steps:

1. Preparing the substrate: Insulating materials are usually used as the substrate, such as FR4, CEM-1 or aluminium substrate etc. FR4 is a common glass fibre reinforced epoxy resin substrate with good insulating properties and heat resistance.

2. Making lines: The process of making conductive lines on a substrate. Traditionally, this was done by photolithography and development using a photographic film and exposure machine. Nowadays, many circuit board manufacturers have begun to use computerised direct manufacturing (Direct Imaging) technology to transfer the line pattern directly onto the substrate.

3. Surface treatment: In order to increase conductivity and connection reliability, the surface of the circuit board needs to be treated. This can include chemical copper plating, copper plating and other processes to increase the conductivity of the surface.

4. Soldering components: Electronic components are connected to the circuit board through soldering. Solder joints are small pieces of metal on the circuit board that are connected to the component pins by molten solder.

5. Inspection and Testing: In the final stage of circuit board manufacturing, inspection and testing are required to ensure proper functioning. This can include visual inspection, X-ray inspection, impedance testing, functional testing etc.

Circuit boards are widely used in a variety of electronic products, such as computers, mobile phones, TVs, stereos, automotive electronics, and so on. Different kinds of circuit boards can fulfil different electronic functions, such as power supply circuit boards, signal processing circuit boards, sensor circuit boards and so on.

With the continuous development of technology, the manufacturing technology of circuit boards is also advancing. The application of advanced technologies such as High Density Interconnect (HDI) technology, buried component technology, etc., enables circuit boards to realise more complex electronic functions and finer line layouts.