Understanding Circuit Boards – What Am I Looking At?

Written by: Quintin Bentley Crevling

Don’t worry, you aren’t the first person to look at a circuit board and wonder how the heck it works. These confusing devices have simplified our life and thrust our society into the age of technology. Your computer, cell phone, tablet, TV, game console, car, and even your children’s toys have circuit boards in them. Circuit boards as we know them were first developed in the 1940’s by an Austrian scientist named Paul Eisler.

Before his historic invention, electrical boards were operated using point-to-point wiring that was susceptible to short circuits and worn wires. The new printed circuit boards assembly was much easier to build and would last longer than point-to-point wiring. To understand how a circuit board works you must know what how a circuit board is constructed, how the parts transmit messages, and the various types of circuit boards.

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The purpose of a circuit board is to transmit a message from one pad to the next. These thin green plates have electrical components soldered together to send signals quickly throughout the board and to external components. The circuit board is assembled in four stages. The substrate or base layer of the circuit board is made of fiberglass and provides a rigid surface for the fragile parts to be assembled.

Next, a thin layer of copper is applied to the board to help quickly conduct electronic signals. A thin layer called a solder mask is applied over the copper to insulate the surface and protect against a solder jumper, where unwanted solder connects two adjacent pins. The last layer is a silkscreen where letters and numbers are added to the board to make it easier to assemble and further understand the board.

Circuit boards transmit messages through important parts, such as transistors, diodes, resistors, capacitors, and inductor. Transistors work like a switch that is open and close to allow signals to be transmitted. Diodes allow a current to flow in one direction only. Think of this like a valve shutting off the flow of gas. This allows certain components to accessthe current to perform a function.

A resistor does not do anything to your circuit board, it simply controls the flow of current so components work at the proper voltage.Capacitors and inductors both store energy for the circuit board to operate more efficiently. This allows the circuits to run on various frequencies for optimal performance.

A motherboard is a circuit board that contains the primary components of a computer, or other telecommunication devices. This important part of the computer provides communication to the CPU, RAM, memory, and other components essential to operating the device. Like motherboard is the daughterboard, which is a circuit board that acts as an extension of a motherboard. The most popular daughterboard is an external memory drive. There is no reason to waste valuable computing power on stored memory when you can buy an external hard drive for a few dollars.