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What Is the Role of Electronic Parts on the Circuit Boards?
Tuesday, December 19th, 2023

A circuit board is an independent part of modern electronic devices, equipped with various components that play different roles and functions on the board such as connecting, signal transmission, power distribution, and signal conversion. Theoretically speaking, electronic components are the fundamental units in the devices, and printed circuit board (PCB) serves as a carrier for mounting components, connecting them to completing the functions of electronic systems. Here, we will introduce some common circuit board components and their functions.


What Are Electronic Components?

Electronic components are fundamental building blocks used in the construction of electronic circuits and systems. These components manipulate electrical signals to perform specific functions in electronic devices. Based on their purpose and functionality, electronic components can be categorized into two major types: passive components and active components.

Passive electronic components mainly include resistors, capacitors, inductors, power filters, and so on. They do not have active operational functions such as amplification or signal control. Instead, passive components can only consume or store electrical energy. In electronic systems, their main roles include signal transmission, distribution, filtering, isolation, and other similar functions.

Active electronic components, on the other hand, include transistors, field-effect transistors (FETs), integrated circuits (ICs). Unlike passive components, active components have the ability to actively amplify, control, and manipulate signals related to current, voltage, frequency, and more. They play a crucial role in electronic systems, enabling active operations and functionalities.


What Is the Functionality of Common Components on PCB?

On an assembled circuit board (PCBA), we can see various of components on its surface. Different components play its unique role and have different function. Here we will introduce the function of common components.

  • Resistor

A resistor is a component used to restrict the flow of electric current. Its purpose is to control the magnitude of current by adjusting its resistance value, ensuring appropriate current adjustment within the circuit.

  • Capacitor

The capacitor has the ability to store charge and release it when needed. Its function is to smooth power supply voltage, stabilize current, and in some cases, perform signal filtering to accomplish signal conditioning. Resistors and capacitors are two common types of electronic components.

  • Diode

Diode is a type of component with unidirectional conductivity. The uses of diode enable to allow current to flow in one direction while blocking reverse current. It is commonly used in power supplies, rectifiers, and other circuits.

  • Transistor

A transistor functions in amplification and switching in a printed circuit board. Its role is to amplify electronic signals, control the flow of current, and it is widely used in circuits such as amplifiers and logic gates.

  • Integrated Circuit (IC)

Integrated circuit is a very important components in those small size circuits, because it can integrate multiple functional circuits onto a single chip. That means it can save space if your design has limited space, enhance system performance and reliability of devices. Integrated circuits find widespread applications in areas such as computers, communication systems, and embedded systems.

  • Inductor

The working principle of inductor is similar to a capacitor, but the different is an inductor has the ability to store and release energy while capacitor is to store and release charge. Its main function is to accomplish energy conversion and distribution in a circuit. Inductors are commonly used in circuits for filtering, power supplies, and more.

  • Variable Resistor

A variable resistor allows for the adjustment of resistance and it always used for modifying circuit characteristics by changing the resistance value. Variable resistors are commonly used in circuits for functions like volume control, light intensity adjustment and some other devices that need to adjust the resistance.

  • Light Emitting Diode (LED)

LED chips is a component that we can see everywhere need to light up. It converts electrical energy into light energy. Its function includes emitting light for indicators, illumination, and it is widely used in circuits such as display screens and indicator lights.

  • Power Module

Power module is always designed to provide the electrical energy required by a circuit. Using power to stabilize output voltage and current, protecting the circuit from external power fluctuations.

  •  Sensor

A sensor can perceive physical quantities or signals in the surrounding environment and convert them into electrical signals. Its function is to enable interaction between the circuit and the external environment. Sensors find wide applications in areas such as automatic control, the Internet of Things (IoT), and more.


In summary, the various components on a circuit board have their specific roles, work in conjunction with each other, and collectively achieve the functionality and objectives of the circuit. Understanding the functions of these components allows for a better grasp of the working principles of circuit boards, providing reference and guidance for the design and maintenance of electronic products.

However, for some reasons, inspect the components before PCB assembly is the main method that ensures the reliability of a PCBA. In our next post, we will share how to make the incoming inspection for electronic components, leave your messages if you are interested in it.

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What is a E-Tester & how E-tester test PCB?
Saturday, December 2nd, 2023

We often receive this question from customer” what is a E-Tester?” and” how to do E-Test for FR4 PCB?” Hereby I would like to share with you how to use E-Tester to test PCB.

Best Technology in FR4 PCB circuit manufacturing filed since year 2006, we have more than 17 years experiences in PCB fabrication process. We can provide from the design to turn key service for our customer.

Let us come to today’s topic, now what is a E-Tester?

What is a E-tester?

E-Tester is tooling for test PCB during volume production. E-Tester was used to detect the electrical performance of PCB. It is the essential process to test the PCB by this tester before shipment.

As you may know that during PCB process flow, it might be caused some defects by external factors and this is unavoidable.

So, in order to reduce the loss before PCB goes to the next stage when it is assembled with components, Therefore, the E-Test plays important role in PCB quality control to segregate PCBs with defects from shipment to customers and that’s why most of customers require their PCB manufactures to do 100% E test before shipment.


The E tester mainly checks the open/short circuit for FR4 PCB.

How to do E-test?

Firstly, set up the E-tester on the testing machine and up test datasheet on the computer. Put the board to the E-tester to test the open/short circuit for board and dielectric strength.

Shorts Test: Check to make sure that NO current flows between separate nets by measuring the amount resistance between them.

Opens Test: Check to make sure there is current flow from one “node” to the next for every net on the board.


During the testing, test whether there is short circuit between different network routes of PCB; test whether the PCB network is open to each PAD, and whether the hole is open; Finally, Insulation strength test and the Impedance test.

If the trace open is found on the bare board, the failure location could be repaired or the bare board has to be scrapped. On the other hand, the cost will be increased when PCB goes to the next stage when it is assembled with components, mainly are the sorting cost, component cost and the assembly cost. The compensation ratio is 10 times or even more than the PCB cost and this damages PCB manufacturer’s profit. The worse case is when PCBA is installed onto the end product, the loss caused by defected PCB could be very painful, say up to thousand times of PCB cost. Therefore, the E-Test plays important role in PCB industry to segregate PCBs with defects from shipment to customers and that’s why most of customers require their PCB suppliers to do 100% E test before shipment.

If you want to know more about testing for FR4 PCB board, welcome to visited www.bestpcbs.com or email us, we are very happy to answer your question.

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