Chapter 2 – Basic component names

Basic Hardware Names

Have you ever seen something like the image shown above. That is a complete functioning circuit board of Tecno M7 device. That is an example of a hardware. Hardware is part of a device that can be seen and touched. Example of a Hardware is the screen of your device, the camera, the vibrator, the headset jack and so on.

In this chapter, we will discuss some common hardware and how they operate. Likely, these are the first issues you may face as a beginner if you start mobile device repair.

1. PCB (Production Circuit Board)

A production circuit board (some also refer to it as a printed circuit board), is a board containing electrical component that makes a device to function. Some of the electrical components that can be found in the PCB of a mobile device are the resistors, the coils, the speakers etc. The size and shapes of PCB varies depending on the choice of device manufacturers.

The board in itself is not made of conductive materials (metal). It cannot conduct electricity. The way an electric circuit system will work will be designed by manufacturer first and then printed on the non-conduction PCB.

2. MIC

When making a call with your phone, the MIC (which means the microphone) record what you say during the call and makes it available to be transmitted to the person you are talking with. If the MIC in a phone is bad and you make a call with that phone, the other person will not hear you. If you record any sound with the phone, it will not work.

There are many types of MIC. Some have two terminals (legs) and others have 4 terminals. The most common type of MIC is the 2 legged universal MIC (mouthpiece).


Phone speakers are like the ones in your home televisions. The difference is that your television has a big speaker while your phone has a small one. There are many different types of speakers. One common thing with these speakers is that all of them has only 2 terminals. These speakers allow us to listen to music. In most Chinese phones, to replace a speaker, you will have to remove the faulty one and then solder the working one. But in Nokia phone, you don’t need soldering to remove and replace a speaker. How to solder the speaker and other components will be considered in chapter 5.

4. REC (Ear piece)

The REC is a speaker that is very small in size and has lowered volume that allowed only a the person making or receiving calls to hear what is being said. The location of the REC is mostly at the top of the PCB where people hold close to their ears. In some Phones, the main speakers meant for music also serve as the REC. When playing musics, the speaker is activated with moderate volume, but when making calls, the speaker reduces the volume to serve as REC. If the caller puts the call on speaker, the speaker volume increases.


The USB connector (port) does two things (actually there is more). The first function is to charge the phone and the second is to transfer file between the phone and the computer. Different phones use different USB connector, but they all have the same working method. Their contact terminals that connect them to the PCB are mostly 5. Only some Samsung Phones and few others that don’t. Infinix phones, Tecno phones, and Nokia phones all have different USB connectors but the same 5 terminals.

6. Screen

The screen is the part of the device that shows all the graphics of the phone. There are two types of screen – those that are soldered to the PCB and those that are clipped to the PCB. All screens has white light attached to the and there lights are refered to as “LED”. If these light stop functioning, the screen will continue to work but a user of that phone will not see anything in the screen. The Picture below, indicate different screens with their terminals.


Most android phones do not use keypads, but MOS phones do. Without the keypad, these phones cannot be operated. When you press a key in the keypad, two points touches each other. This make a number that corresponds with what you press to appear in the screen.


If the battery of your phone is not inbuilt, then you already know that the battery get connected to the phone through contact to the terminals from the phone. These terminals are 3 for some phone, while others phones have more. When the battery is connected to the device, voltage is passed across points in the PCB. These battery terminals connecting the battery to the PCB sometimes gets damaged, but can bu replaceable. In some few devices such as some blackberry phone, the battery terminals are inserted into a redesigned compartment in the phone casing without soldering. In other phones, it is firmly soldered to the PCB.


Hardware are the components of a device that can be seen and touched.
Hardware are replaceable
Some components found in phones are
USB Connector
Battery terminal

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