Circuit Boards are a vital part of every computer, digital camera and electronic device you own. They provide a way to connect, organize and route electrical signals from a microprocessor, memory and other components. They are also a protective housing for the sensitive circuitry. Depending on their design, they are capable of handling a variety of voltages and speeds. If you want to recycle a PCB, be sure to follow any local regulations for safe disposal.
The evolution of PCBs started with a need for a more reliable way to connect and power electronic components. While the Jazz Age ended with a devastating stock market crash and the Great Depression brought chain gangs, bread lines and cramped tenements, military intelligence agencies began working to adapt PCB technology to more rugged devices like radar equipment and radio transmitters.
These early PCBs used a base material called dielectric composite materials. These are comprised of a resin matrix, a filler such as woven fiberglass or non-woven paper and an insulator such as a glass fiber or mica. The copper on the bare board is then either printed on or electroplated using an additive process. Printed on is the traditional method which uses acid-resistant ink to draw the wiring pattern. After the ink is removed, copper on the unexposed area remains. A metal is then deposited on the copper, such as aluminum. The resulting plate is then photographed to make a stencil for the additive process. The stencil is used to deposit the metal ions which are then plated on the copper. The resulting copper is then soldered to the pads of the components, making a conductive path between the components.
One of the most important functions of a PCB is to supply power to its various components. To do this, it is designed with a number of power connectors, which connect to the computer’s power supply. This ensures that the correct amount of current is provided to each component, preventing damage due to over or undervoltage.
In addition to power connectors, a circuit board may include other types of connectors for data transmission and signal processing. These include RF connectors, which are used to transmit electronic data and voice. Other types of connectors are HDMI, USB and RCA. The use of these connections increases the versatility of a circuit board and makes it easier to upgrade its functionality as your needs change.
Originally, How do circuit boards work were constructed manually. A schematic diagram was drawn on a clear mylar sheet that was two or four times the size of the actual PCB. Component pin pads were then laid out on the mylar and traces drawn to connect them. Rub-on dry transfers of common pad sizes increased efficiency. Eventually electronic design automation (EDA) software made this process quicker and more accurate.
A legend, which contains component designators, switch settings and test points is then printed on the board with a silkscreen. Typically white, but any ink color can be used. These markings are used for assembling, testing and servicing the board.