SMD Capacitor

Step by step Cellphone repair tutorial - Basic to Advance - Topic 02

- The capacitor's function is to store electricity, or electrical energy.
- The capacitor also functions as a filter, passing alternating current (AC), and blocking direct current (DC).
- This symbol -||- is used to indicate a capacitor in a circuit diagram.

Capacitors are used in circuits to store electrical charge for a short time. They can be either polarised or non-polarised, which mans either that they have to be connected the right way round (like the LED) or you can connect them anyway you like.. (like the resistor). If a capacitor is polarised it has a slightly different symbol on the circuit diagram and it is marked on the case with a plus-sign (+) or a minus sign (-)

Tantalum capacitors are used in smaller electronic devices including portable telephones, pagers, personal computers, and automotive electronics.
Tantalum capacitor SPECIFICATION:
Operating Temperature Range : -55 to + 125°C
Rated Working Voltage Range : 4 to 50 V DC
Nominal Capacitance Range : 0.1 to 1500μf
Capacitance Tolerance : ±20% ±10% (120Hz, ±20°C)
Leakage Current : Not more than 0.01CV [μA] or 0.5μA whichever is greater

Polarized Capacitor
Polarized capacitors are the electrolytic type or tantalum type.
Polarized capacitors have large leakage current if the voltage is inverted.

The tantalum capacitor is a highly reliable type of solid capacitor or electrolytic capacitor. Surface mount tantalum capacitors are increasingly being used in circuit designs because of their volumetric efficiency, basic reliability and process compatibility.

Non Polarized Capacitor
There are two types of non polarized capacitors. The plastic foil that are non polarized by nature and electrolytic non polarized capacitors that are actually two capacitors in series (back to back) so that the result is non polarized with half the capacitance.
P-C has a small size with the large capacitance, is used only in DC circuits or circuits related to DC current.


non-polarized caps are typically used in low voltage situations, both AC and DC. Polarity is not critical. Measured in pico farads typically.

A basic three symbol code is used on some capacitors. The first two marked digits are the first two digits of the value, and the third digit is a multiplier. This marking system is exactly the same as the marking system used for ceramic capacitors. All the values marked are in pico Farads.

Tolerance
All components differ from their marked value by some amount. Tolerance specifies the maximum allowed deviation from the specified value. Tolerances are normally expressed as a percentage of the nominal value.
For example, a component with a marked value of 100 and a tolerance of 5% could actually be any value between 5% below the marked value (95) and 5% above the marked value (105).

Decimal multiplier prefixes are in common use to simplify and shorten the notations of quantities such as component values.
Capacitance, for example, is measured in Farads, but the Farad is far too large a unit to be of practical use in most cases. For convenience, we use sub-multiples to save a lot of figures. For example, instead of writing 0.000000000001 Farads, we write 1pF (1 picofarad).
The more common prefixes and the relationships to one another are as follows.

Abbrev.	Prefix	Multiply by	or
p	pico	0.000000000001	10-12
n	nano	0.000000001	10-9
µ	micro	0.000001	10-6
m	milli	0.001	10-3
-	UNIT	1	100
k	kilo	1000	103
M	mega	1000000	106

Units
1000 pico units	=	1 nano unit
1000 nano units	=	1 micro unit
1000 micro units	=	1 milli unit
1000 milli units	=	1 unit
1000 units	=	1 kilo unit
1000 kilo units	=	1 mega unit

Step by step Cellphone repair tutorial - Basic to Advance - Topic 02

SMT Resistor

Step by step Cellphone repair tutorial - Basic to Advance - Topic 02

Resistor
A resistor is a two-terminal electrical or electronic component that opposes an electric current by producing a voltage drop between its terminals in proportion to the current, that is, in accordance with Ohm's law: V = IR. The electrical resistance R is equal to the voltage drop V across the resistor divided by the current I through the resistor. Resistors are used as part of electrical networks and electronic circuits.

Surface mount technology (SMT) is a method for constructing electronic circuits in which the components (SMC, or Surface Mounted Components) are mounted directly onto the surface of printed circuit boards (PCBs). Electronic devices so made are called surface mount devices or SMDs
You can refer only its value by an aide of Schematic Diagram Available for that certain products. Or you can Identify and check its value by using Resistance Tester...

Unmarked value

Printed value

The SDM Resistor
Surface mount resistors are typically been comprised of a flat rectangular resistive metal strip with high conductivity metal terminals welded to the ends of the resistive metal strip to form the electrical termination points.
A protective coating is then applied over the resistive material to provide protection from various environments to which the resistor may be exposed as well as providing strength to the resistor.

There are two types of surface mount resistors used in an electronic circuit board-the 3-digit and 4-digit code SMD. The first two digits represent the two digits in the answer. The third digit represents the number of zero's you must place after the two digits. The answer will be in Ohms. For example: 104 which mean 10 0000 (4 zero's) and the final answer is 100k. Let's calculate the 4 digit SMD, 1182 which mean 118 00 (2 zero's) and the final answer is 11.8k.

The answer will be in Ohms. For example: 104 which mean 10 0000 (4 zero’s) and the final answer is 100k. Let’s calculate the 4 digit SMD, 1182 which mean 118 00 (2 zero’s) and the final answer is 11.8k.

Step by step Cellphone repair tutorial - Basic to Advance - Topic 02

Electronic Components: Symbols & Functions

Step by step Cellphone repair tutorial - Basic to Advance - Topic 02

Circuit symbols are used in circuit diagrams which show how a circuit is connected together. The actual layout of the components is usually quite different from the circuit diagram. To build a circuit you need a different diagram showing the layout of the parts on stripboard or printed circuit board.
Electronic Components: Symbols & Functions

Step by step Cellphone repair tutorial - Basic to Advance - Topic 02

The Parallel Circuit

Step by step Cellphone repair tutorial - Basic to Advance - Topic 02

Like the series circuit, parallel circuits also contain a voltage (current) source as well as wires and other components. The main difference between a series circuit and a parallel circuit is in the way the components are connected. In a parallel circuit the electricity has several paths that it can travel.
Notice the picture above, the electrons flowed through both loads at the same time. In our series circuit, all the electrons flowed through all the components in order. With the parallel circuit, some electrons go through one load and some go through the other load, all at the same time. At point A, the total current splits up and takes different paths before the circuit joins back together again at point B.

A parallel circuit exists whenever two or more components are connected between the same two points. Those two points in this circuit are points A and B. Both resistors connect to both points A and B.

Each parallel path is called a branch of the parallel circuit.This parallel circuit contains 3 branches (two resistors and a voltmeter), which means the electron current goes through all three branches at the same time. We put a voltmeter on this second circuit to show an important fact. In the last 4 circuits you made, you included an ammeter into them. Ammeters must always be placed in series in a circuit, otherwise they will not work. The voltmeter we added in the last circuit has a different requirement in order to work. Voltmeters must be placed in parallel with the circuit in order to work. This is because voltage meters measure the difference in electromotive force (EMF) from one area to another. They are used to measure the difference in EMF on one side of a component compared to the other side of the component. In our homes, most circuits contain 120 volts of EMF.

Review

1. When some of the components are connected parallel with each other, they form a parallel circuit.
2. A voltmeter must be wired in parallel in a circuit in order to measure the difference in EMF from one point to another.
   

Step by step Cellphone repair tutorial - Basic to Advance - Topic 02

The Series Circuit

Step by step Cellphone repair tutorial - Basic to Advance - Topic 02

A series circuit has more than one resistor (anything that uses electricity to do work) and gets its name from only having one path for the charges to move along. Charges must move in "series" first going to one resistor then the next. If one of the items in the circuit is broken then no charge will move through the circuit because there is only one path. There is no alternative route.Load defined
The light bulb is considered a load in this circuit. You might think of a load as anything that is using the energy that is being delivered by the electric current in a circuit. It could be anything from a light bulb to a computer to a washing machine and so on.

The light bulb in the first circuit was actually acting like a resistor because it only allowed a certain amount of current to flow through it. If there are no resistors or components that act like resistors to slow the flow of electrical current, too much current may flow through the circuit and damage its components or wires. Too much current flowing through a component results in the generation of heat that can melt the conductive path through which the electrons are flowing.
We cannot see any work being done since there is no light bulb, but there is current actually flowing inside. We know the current is flowing because the ammeter is indicating this. It is important to know that we may not be able to tell whether current is flowing through a circuit without test equipment, such as our ammeter connected to the circuit. Electricity can be very dangerous and experiments like these should never be conducted without adult supervision. Never work with electricity unless you are trained to know how to work with it safely.

Review

1. When all the components are in line with each other and the wires, a series circuit is formed.
2. A load is any device in a circuit that is using the energy that the electron current is delivering to it.

Step by step Cellphone repair tutorial - Basic to Advance - Topic 02

What is a Multitester?

Step by step Cellphone repair tutorial - Basic to Advance - Topic 02


A multitester or multimeter is a device which can be used to gather data about electrical circuits. A basic multitester can measure resistance, voltage, and continuity, while more advanced versions may be able to provide additional data. This tool can be very useful to have around the house, and anyone who plans on doing electrical repairs should most definitely use a multitester for safety reasons. Multitesters can be used with the current off or on in most cases, although using the device with the current on can sometimes result in damage to the device.

This device is hand held, and powered by batteries. It consists of two probes attached to a central pack which can be digital or analog. The device has a series of buttons or switches which can be used to set the type of measurement being performed. A rubber housing may be used to make the multimeter easier to handle.

Continuity, the most basic measurement provided by a multitester, determines whether or not a circuit is complete. For a continuity test, the device is set to “ohms” and AC or DC, depending on the current being measured, before the probes on the device are inserted into the circuit. If the circuit is complete, the readout will measure between 0 and .05 ohms. A measurement of infinity

Click on the links below to see how to use a multitester

Analog Multitester

Step by step Cellphone repair tutorial - Basic to Advance - Topic 02

Ohm's Law

Step by step Cellphone repair tutorial - Basic to Advance - Topic 02

Ohm's law - Ohm's Law defines the relationships between (P) power, (E) voltage, (I) current, and (R) resistance. One ohm is the resistance value through which one volt will maintain a current of one ampere.

What is Currenr? - ( I ) Current is what flows on a wire or conductor like water flowing down a river. Current flows from negative to positive on the surface of a conductor. Current is measured in (A) amperes or amps.

What is Voltage? - ( E ) Voltage is the difference in electrical potential between two points in a circuit. It's the push or pressure behind current flow through a circuit, and is measured in (V) volts.

What is Resistance? - ( R ) Resistance determines how much current will flow through a component. Resistors are used to control voltage and current levels. A very high resistance allows a small amount of current to flow. A very low resistance allows a large amount of current to flow. Resistance is measured in ohms.

What is Power? - ( P ) Power is the amount of current times the voltage level at a given point measured in wattage or watts.

Ohm's Law Pie Chart

Info: Ohm's Law was named after Bavarian mathematician and physicist Georg Ohm.

OHM's Law Calculator

Step by step Cellphone repair tutorial - Basic to Advance - Topic 02

What is Electronics?

Step by step Cellphone repair tutorial - Basic to Advance - Topic 02

What is Electronics?
Electronics is the branch of science and technology which makes use of the controlled motion of electrons through different media and vacuum. The ability to control electron flow is usually applied to information handling or device control. Electronics is distinct from electrical science and technology, which deals with the generation, distribution, control and application of electrical power. This distinction started around 1906 with the invention by Lee De Forest of the triode, which made electrical amplification possible with a non-mechanical device. Until 1950 this field was called "radio technology" because its principal application was the design and theory of radio transmitters, receivers and vacuum tubes.

Most electronic devices today use semiconductor components to perform electron control. The study of semiconductor devices and related technology is considered a branch of physics, whereas the design and construction of electronic circuits to solve practical problems come under electronics engineering.

Step by step Cellphone repair tutorial - Basic to Advance - Topic 02

Learn the 2 Block Diagram of a Cellphone

Step by step Cellphone repair tutorial - Basic to Advance - Topic 01

How Cellphone Works?

A Cell-phone handset is basically composed of two sections,
which is RF and Baseband Sections.

Radio Frequency (RF) - The spectrum of electromagnetic energy between audio and light: 500 KHz to 300 GHz.

Cell phones communicate with nearby cell towers through RF waves, a form of energy located on the electromagnetic spectrum between FM radio waves and microwaves. Like FM radio waves, microwaves, visible light, and heat, they are a form of non-ionizing radiation.

Baseband
Describing a telecommunication system in which information is carried in digital form on a single unmultiplexed signal channel on the transmission medium.
Any frequency band on which information is superimposed, whether or not the band is multiplexed and information is sent on subbands. In this usage, there is sometimes the meaning that the frequency band is not shifted to some other frequency band but remains at its original place in the electromagnetic spectrum.

Cell-phone have three sections since baseband is differentiated by into two which is the Analog and Digital function while the RF section remains as a whole circuit section.. which is the following cosists.

1. Radio Frequency (RF Section - receiver and transmitter)
2. The Analog Baseband Processor
3. And the Digital Baseband Processor.

Radio frequency elements
The radio frequency section of the mobile phone is one of the crucial areas of the cell phone design. This area of the mobile phone contains all the transmitter and receiver circuits. Normally direct conversion techniques are generally used in the design for the mobile phone receiver.

The signal output from the receiver is applied to what is termed an IQ demodulator. Here the data in the form of "In-phase" and "Quadrature" components is applied to the IQ demodulator and the raw data extracted for further processing by the phone.

On the transmit side one of the key elements of the circuit design is to keep the battery consumption to a minimum. For GSM this is not too much of a problem. The modulation used is Gaussian Minimum Shift Keying. This form of signal does not incorporate amplitude variations and accordingly it does not need linear amplifiers. This is a distinct advantage because non linear RF amplifiers are more efficient than linear RF amplifiers.

Analog Baseband Processor
A/D and D/A section
The Analog Baseband compose of two parts, the analog-to-digital (A/D) signal and digital-to-analog (D/A) signal converters that link RF transceiver and the baseband circuits.

Control section
This is the section acts as the controller of the the input and output of any analog and digital signal.
Power Management
A power management section in mobile phones is designed to handle energy matters that is consumed in mobile phones. There are two main sub sections in a single power section.

Charging Section

A power distribution section is designed to distribute desired Voltages and currenst to the other sections of a phone. this section takes power from a battery (which is figured commonly 3.6 Volts)and in some places it converts or step down to various volts like 2.8 V 1.8V 1.6V etc.while on other place it also steps up the voltage like 4.8 V. this section is commonly designed around a power IC(and integrated circuit) which is used to distribute and regulate the voltage used in other components.
The Charging section is based on a charging IC which takes power from an external source and gives it to battery to make it again power up when it is exhausted. this section uses convertibly 6.4 V from an external battery charger and regulates it to 5.8V wile giving it to battery. The battery is made charged by this process and it is ready to use for the next session (a battery session is a time which is provided by the manufacturer of a cell phone for standby by condition of a mobile phone or talk condition.)

Audio Codecs Section
This section where analog and digital audio properties being process like the microphone, earpiece speaker headset and ring-tones and also the vibrator circuits.

Digital Baseband Processor
This is the part where All Application being process. Digital Baseband Processor section is used in mobile phones to handle data input and ouput signal like switching, driving applications commands and memory accessing and executing.
These are the parts and sections o a Digital Baseband Circuit were installed.
CPU
CPU( Centeral Processing Unit) The Central Processing Unit (CPU) is responsible for interpreting and executing most of the commands from the users interface. It is often called the "brains" of the microprocessor, central processor, "the brains of the computer"
Flash and Memory Storage Circuits
*RAM( Random Access Memory)
*ROM,Flash(Read Only Memory
Interfaces such as the following were also part on this section:
*Blutooth
*Wi-fi
*Camera
*Screen Display
*Keypads
*USB

*SIM-CardHere a typical overview of a block diagram on latest mobile phone designs.

Various mobile phones have different concepts and design on every aspects, but the methods and operational flow are all exactly the same. It differs on how and what certain IC chips and parts they are being used and installed to a certain mobile phone circuitry.

Step by step Cellphone repair tutorial - Basic to Advance - Topic 01