What Are The Circuit Board Components Fundamentals

What Are The Circuit Board Components Fundamentals


PCB stands for Printed Circuit Board, a thin insulator plate such as FR-4, coated with a high conductivity material such as copper, connecting the different components assembled on the board. Circuit board components are basic electrical or electronic devices, such as a resistor, capacitor, inductor IC etc., that perform a particular function when supplied with an input signal. Components are welded on the PCB (copper side) with solder, an alloy of different metals, achieving a hard and strong connection (both mechanical and electrical) between the copper circuit on the PCB and the component.




The FR-4 laminated sheet with thin layer of copper makes a skeleton for components placement and soldering. The circuit board components which are placed over the PCB are:

1. Switches: Allows current flow when in ON position otherwise stops current flow

2. Resistor: controls the current flow when applied the voltage across it

3. Capacitor: Stores the electric charge with an existence of a potential difference across it

4. Inductor: Stores magnetic field and opposes the flow of current

5. Diode:  Allows passing current in forwarding direction but stops in the other direction

6. Transistor: A signal amplifying or switching component

The above-mentioned circuit board components are very basic building blocks of electronic components. There are many complex devices which are used in thousands of billions every year in different electronics products.


In a circuit board application, the components are modeled first for schematics and then for PCB layout. The models for schematics are known as component symbols which show the type of components, number, and type of pins and their values. They are made for circuit functionality understanding and easy readability of the drawings.  The component models used for PCB layout are the shape and size exactly what the component looks like in the real world. The PCB model of a component s is called a footprint. In the early times, the electronic components were modeled what they look in x and y-direction i.e. the size in terms of length and width of the component along with their pins position. But nowadays electronic products are becoming more and more complex the footprint s are made in 3D shape i.e. modeling the length, width and height aspects of a component that show the components’ length, width and height feature on the PCB.


Figure 1 shows the different resistor sizes, figure 2 shows the transistor schematic symbols and different packages and figure 3 shows the 3D footprint of an 8-pin SOIC package IC and its soldering on PCB.


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Figure 1: Different sizes and shapes of resistor packages.


The use to which the PCB is to be deployed determines its size and thickness. Standard PCB thickness is deployed in making electronic components, electronic connection providers, and platforms for electronic parts.


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Figure 2: Transistor schematic symbol and different packages


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Figure 3: 8-pin SOIC footprint 3D PCB footprint model and soldering on PCB