Many of you want to learn professional "hardware repair" as ATX power supplies, CRT monitor, LCD, printer, motherboard, laptop ... but do not know anything about electronics?
This from the explanation, because the hardware ultimately is just "electronic devices" that want to fix, we must begin with "basic electronics".
The articles listed below is easier to understand.
Hope it will help you step into a new job access. Click on the link below to view each article.
Basic: Power DC - DC
1 - The basics of electricity1. Atomic structure:
To understand the current nature we know that (knowledge of high school) all the elements are constructed from atoms and each atom of a substance is composed of two parts
- A kernel between the positively charged particles called protons and electrically neutral particles called neutrons.
- The Electron (e) carry negative charges moving around the nucleus.
- Normally, atoms are electrically neutral state that is equal to the number of Proton nuclear electron outside but when external factors such as pressure, temperature, static friction, the effects of magnetic fields. . e is the electron in the outermost layers can be separated from the orbit to become free electrons.
- When an atom loses one or more electronic, we are missing electrons and become positive ions and vice versa when an atom receives one or more additional electron, they become negative ions.
2. The nature of the current and the current direction.
When the electron concentration at high densities on the effects they produce charged
- Current is the flow of charged particles such as electron, ion.
- Afternoon conventional current is from positive to negative (as opposed to the motion of the electrons - going from negative to positive)
3. The effects of electric current:
When a current flows through the wire as the following experiments:
We see that the current created a magnetic field to deflect around the magnet, the current reversal, the magnetic field also redirect => do magnet deflection in the opposite direction.
- Current flowing through the lamp bulb to light and heat energy Siang
- Current flowing through the motor rotates the rotary mechanical energy generated
- When you load the batteries for the battery plates are changed and the current effects of power ..
- Current flowing through the lamp bulb to light and heat energy Siang
- Current flowing through the motor rotates the rotary mechanical energy generated
- When you load the batteries for the battery plates are changed and the current effects of power ..
Such currents have the effect of the thermal effects, mechanical effects and effect of magnetic field effects on chemical and energy.
2 - Current and DC voltage 1. Amperage:
As a specific measure of the intensity of electric current or specific number of electrons passing through the conductor cross section per unit time - is the symbol I
- The current one-dimensional flow in a certain direction from positive to negative by convention or unidirectional flow of free electrons.
The unit of electric current intensity is the ampere and the multiplier:
- Kilo Ampere Ampere = 1000
- Mega Ampere Ampere = 1000.000
- Mili Ampere = 1 / 1000 ampere
- Micro Ampere Ampere = 1/1000.000
2. Voltage:
When the electron density are concentrated in two points A and B if we connect a wire from A to B would appear the motion of electric charges from place to place high density low density, as So we call the two points A and B have different voltage and voltage difference is applied voltage.
- The voltage at point A is called U A
- Voltage at point B called U B.
- The difference in voltage between two points A and B is called the voltage U AB
U AB = U A - U B
- The unit of voltage is denoted Vol U or E units have multiple voltage is
When the electron density are concentrated in two points A and B if we connect a wire from A to B would appear the motion of electric charges from place to place high density low density, as So we call the two points A and B have different voltage and voltage difference is applied voltage.
- The voltage at point A is called U A
- Voltage at point B called U B.
- The difference in voltage between two points A and B is called the voltage U AB
U AB = U A - U B
- The unit of voltage is denoted Vol U or E units have multiple voltage is
- Vol Kilo (KV) = 1000 Vol
- Mili Vol (mV) = 1 / 1000 Vol
- Micro 1/1000.000 Vol = Vol
Voltage can be compared to an average height of the water, if water there are two different heights, when connecting a pipe will have water flowing from high average to below average, while two water elevation in together there is no water flowing through pipes. Electric current is the same if the two point voltage deviation Rachel generates electric current through the wire connecting the two points from the high voltage to low voltage, and if two points are equal, the line voltage in the wire to = 0
3 - The fundamental laws 1. Ohm's Law
Ohm's Law is the law important to remember that we need to think
Amperage in a circuit section is proportional to the voltage at both ends of the circuit and inversely proportional to the resistance of the circuit there.
Formula: I = U / R in which
- I is the intensity of electric current, measured in ampere (A)
- U is the voltage at both ends of the circuit, equal to Vol (V)
- R is the resistance of the circuit, calculated by holding
Circuit section connected in series:
In a circuit with multiple stages connected in series resistance, the voltage at both ends of the circuit by the total pressure drop over the resistor.
- As the diagram above, U = U1 + U2 + U3
- According to Ohm's Law we have U1 = I1 x R1, U2 = I2 x R2,
U3 = I3 x R3, but the circuit is connected in series I1 = I2 = I3 - Pressure drop over the resistor => proportional to the resistance.
Parallel circuit section
In the circuit with many resistors in parallel, the amperage of the total current through the resistor and the voltage drop over the resistor is the same:
- Circuit is U1 = U2 = U3 = E
- I = I1 + I2 + I3 = U1 I1 and I2 x x R1 = R2 = R3 I3 x
- Current intensity is inversely proportional to resistance.
3. Power and performance:
* Power.
When current flows through devices such as light bulbs => as light bulbs, running through the engine => rotary engine such as the current work was born. The electric current is called the power, symbolized by W, in practice it is often used Wh, KWh (Kilo watt hour)
* Power.
When current flows through devices such as light bulbs => as light bulbs, running through the engine => rotary engine such as the current work was born. The electric current is called the power, symbolized by W, in practice it is often used Wh, KWh (Kilo watt hour)
Power calculation formula is:
W = U x I xt
- In which W is the power measured in June (J)
- Voltage U is equal to Vol (V)
- I is current measured in ampere (A)
- t is time in seconds (s)
* Power.
Current capacity of the power consumed in a second, power is calculated by the formula
Current capacity of the power consumed in a second, power is calculated by the formula
P = W / t = (U. I. T) / t = U. I
According to Ohm's Law we have P = UI = U 2 / R = RI 2
In nature there are some substances that can suck the iron called a natural magnet.
In one test compound steel or steel to form artificial magnet.
Magnets always have two poles is the northernmost North (N) and southern South (S), if a bar magnet close to 2, we again are two new magnets have two poles N and S - that is the magnet nature does not divide ..
Magnets usually used to produce electrodynamic speakers, microphones or DC motors.
* From the
The magnetic field is the space around a magnet transmission from nature to the magnetic material, magnetic field is the set of field lines go from north to south pole.
* The intensity of the magnetic field
As characteristic quantities of the magnetic field strength, denoted as H unit is A / m
As characteristic quantities of the magnetic field strength, denoted as H unit is A / m
* Inductance
Is a measure of specific magnetic materials are affected by magnetic fields, inductance depends on the material. VD Iron has a stronger sense of the word several times. Inductance is calculated by the formula
Is a measure of specific magnetic materials are affected by magnetic fields, inductance depends on the material. VD Iron has a stronger sense of the word several times. Inductance is calculated by the formula
B = μ.H
In which B is the magnetic feel
μ: is the magnetic permeability
H: the magnetic field strength
μ: is the magnetic permeability
H: the magnetic field strength
* From the Public
As the number of lines passing through a unit area, the flux ratio with the magnetic field technology.
As the number of lines passing through a unit area, the flux ratio with the magnetic field technology.
* Application of permanent magnets.
Permanent magnet is used in many electronic devices, they are used to produce the Speaker, Micro and the DC motor.
Permanent magnet is used in many electronic devices, they are used to produce the Speaker, Micro and the DC motor.
The experiment showed that when the external switch is closed, electric current through the lamp as light bulbs and electric current through the wire generates a magnetic field deflect a magnetic needle.
When the reverse current, a magnetic needle shows deflection in the opposite direction, thus reversing currents create a magnetic field also flips.
When the reverse current, a magnetic needle shows deflection in the opposite direction, thus reversing currents create a magnetic field also flips.
2. The magnetic field of electric current through the coil.
- When current flows through it to the coil, the coil inside the magnetic field appear as parallel lines, if core coil is replaced with steel core, the magnetic field concentrated on the steel core and steel core into a male electromagnet, if we reverse the magnetic field current also redirects
- Fixed DC current passing through the coil creates a magnetic field fixed, variable current passes through the coil creates a magnetic field variation.
- Varying magnetic field is characterized will generate induced voltage on the coils located in areas affected by the magnetic field, magnetic field is not fixed traits.
- Application:
The magnetic field generated by the coil has many practical applications, an application that is often encountered in electronic equipment such as electromagnetic relays.
Electromagnetic relays
When electric current through the coil, the coil core becomes a magnet drawing metal bar and the switch is closed, the effect of the relay is to use a small electric current to control a large current loop closure for more than time.
3. Electromagnetism
If there is a wire placed in a magnetic field when electric current through the wire a repulsion => it is the electromagnetic force, if the wire to free them moves in a magnetic field, this principle is applications when speakers produce an electromotive force.
If there is a wire placed in a magnetic field when electric current through the wire a repulsion => it is the electromagnetic force, if the wire to free them moves in a magnetic field, this principle is applications when speakers produce an electromotive force.
Principle of operation of the speaker (Speaker)
The coil is attached to the speaker membrane and placed in a strong magnetic field between the two poles of the magnet, S pole core, the pole N is around, when the alternating current runs through the coil, under the effect of electromagnetic forces coil moves, the moving speed of the coil depends on the frequency of the alternating current, moving coil speaker is trying to film the speaker membrane motion, if motion at frequencies> 20 Hz are will create a sound wave frequency in the frequency range the human ear to hear.
4. Electromagnetic induction.
Electromagnetic induction phenomenon is induced voltage of the coil is placed in a varying magnetic field.
For example, a coil wound around a steel core, while the alternating current runs through the emergence of a steel core varying magnetic field, if we wrap up with a different coil steel core coil, the two new induced voltage appears. The body coil voltage, and the induced voltage generated and reverse current into the afternoon.
Electromagnetic induction phenomenon is induced voltage of the coil is placed in a varying magnetic field.
For example, a coil wound around a steel core, while the alternating current runs through the emergence of a steel core varying magnetic field, if we wrap up with a different coil steel core coil, the two new induced voltage appears. The body coil voltage, and the induced voltage generated and reverse current into the afternoon.
Basic AC
AC power line changes direction and value over time, these changes are often circulating in a certain period.
The above is the alternating current sine, square and pulse spike.
Cycle and frequency of alternating current.
The cycle of alternating current symbol T is the period that AC repeat previous position, the period is in seconds (s)
AC Frequency: The number of times to repeat the old status of the alternating current in a second symbol is F units of Hz
The cycle of alternating current symbol T is the period that AC repeat previous position, the period is in seconds (s)
AC Frequency: The number of times to repeat the old status of the alternating current in a second symbol is F units of Hz
F = 1 / T
Phase AC:
Referring to the phase of the alternating current is often said to the comparison between the two AC have the same frequency.
* Two phase AC electric current is two times with increasing voltage and decreased with the same:
Referring to the phase of the alternating current is often said to the comparison between the two AC have the same frequency.
* Two phase AC electric current is two times with increasing voltage and decreased with the same:
Two-phase alternating current
* Two phase alternating current: electric current is two times the voltage increments varied.
Two-phase alternating current
* Two reverse-phase alternating current: electric current is two 180 degree phase shift, when the current is increased, then decreased other current and vice versa.
Two reverse-phase alternating current
The amplitude of the AC
The amplitude of ac voltage peak value of the dien.xoay way, this amplitude is higher than the voltage that is measured from the clock
The amplitude of ac voltage peak value of the dien.xoay way, this amplitude is higher than the voltage that is measured from the clock
Effective value of alternating current
Usually the measured value from the clock and also the voltage value is indicated on the power adapter Zac electronic devices., 220V AC source example that we are using is only effective values, the economic peak amplitude of 220V AC voltage of about 220V x = 1.4 was approximately 300V
Usually the measured value from the clock and also the voltage value is indicated on the power adapter Zac electronic devices., 220V AC source example that we are using is only effective values, the economic peak amplitude of 220V AC voltage of about 220V x = 1.4 was approximately 300V
The production of alternating current.
AC Power depends on the intensity, voltage and phase shifts between the two quantities above, the production is calculated by the formula:
AC Power depends on the intensity, voltage and phase shifts between the two quantities above, the production is calculated by the formula:
P = UIcosα
- In which U is the voltage
- I is the current
- α is the phase angle between U and I
=> If the alternating current passing through the resistor, the deviation of its middle phase U and I are α = 0 then cosα = 1 and P = UI
=> If the alternating current passes through the coil or capacitor is the phase difference between U and I is +90 degrees or-90do, where cosα = 0 and P = 0 (the production of alternating current passing through capacitor or electric coil is = 0)
2 - AC line passing through R, C, L 1. Alternating current goes through resistor
Alternating current passes through the resistor, the current and voltage in phase with each other, ie when the voltage increases, the peak current through increased maximum return. Such alternating current with direct current properties as passing back thuan.do can apply the formula of direct current to alternating current goes through resistor
I = U / R or R = U / I Ohm's law formula
P = UI formula for calculating the production
2. Alternating current passes through the capacitor. Alternating current passes through the capacitor, the more electricity will soon phase voltage 90do
AC power line soon
phase voltage than 90 degrees when passing capacitors
* The AC will be gathered together to go through with an impedance block called ZC, and ZC is calculated by the formula phase voltage than 90 degrees when passing capacitors
ZC = 1 / (2 x 3.14 x F x C)
- ZC is a solution in which resistance (Ohm units)
- F is the frequency of alternating current (units of Hz)
- C is the capacitance of the capacitor (in units of μ FARA)
This formula shows the resistance capacity of the capacitor is inversely proportional to frequency of alternating current (ie, the higher frequency capacitors easily pass through) and the rate of convergence nghic with capacitance (ie capacitance capacitors have large, the alternating current passes through more easily)
=> The DC is the frequency F = 0 so that ZC = ∞ so that no direct current passes through the capacitor.
3. Alternating current passes through the coil.
When alternating current passes through the coil creates a magnetic field variations and magnetic field variation of the induction coil to which an induced voltage in reverse, so that the coil tends to resist the alternating current passing through it, this fight is the inductance of the coil denoted by Z L
When alternating current passes through the coil creates a magnetic field variations and magnetic field variation of the induction coil to which an induced voltage in reverse, so that the coil tends to resist the alternating current passing through it, this fight is the inductance of the coil denoted by Z L
Z L = 2 x 3.14 x F x L
- Where Z L is the inductance (in units of Ohm)
- L is the inductance of the coil (the unit is Henry) L depends on the number of turns winding and core materials.
- F is the frequency of alternating current (units of Hz)
From the above formula shows, the coil inductance is proportional to the frequency and the inductance of the coil, the higher the frequency passes through the coil is more difficult => properties of the coil as opposed to convergence power.
=> With direct current to the coil L, then Z = 0 ohm, so the direct current through the coil to be only net effect of the resistor R only (or net resistance of the coil is measured by the clock universal), if the net return of the coil is relatively small direct current through the coil will be a short circuit.
* AC power line passes through the coil, the current slow-phase voltage by 90 degrees compared to the mean voltage increases faster when the coil current.
AC current is slow
than 90 degrees phase voltage going through the coil
than 90 degrees phase voltage going through the coil
=>> Because of the phase difference between current and voltage passing through the capacitor and the coil, so we can not apply Ohm's law to AC circuit as the participation of L and C are.
=>> Regarding the export, the AC was not born when they pass though L and C U> 0 and I> 0.
4. Synthesis of two alternating current on the same circuit
* On the same circuit, if there are two phase alternating current, the voltage amplitude of the voltage will be equal to the sum of two components.
* On the same circuit, if there are two phase alternating current, the voltage amplitude of the voltage will be equal to the sum of two components.
Two current phase amplitude will increase.
* If the same circuit, if there are two reverse-phase alternating current, the voltage amplitude is equal to the voltage signal into two parts.
Two reverse-phase currents, the amplitude decreases
Basics: Using the VOM meter
Measured by clock Guide (VOM) 1) Introduction of a multimeter (VOM)
A multimeter (VOM) is a device which is indispensable to any electronic technician, the multimeter has four main functions Testers, measure DC voltage, AC voltage measurement and current measurement.
The advantage of the fast clock is measured, check the variety of components, see the release of the load capacitor, but this clock has limited accuracy and low resistance between the fins when 20K/Vol measured on the circuit for low line pressure drop they are.
2) How to measure AC voltage.
Use a multimeter to measure AC voltage
When we measure the ac voltage switch on the scale AC scale, to scale the high AC voltage to be measured over a step, for example if we measure the voltage AC220V to 250V AC scale, if we lower scale voltage to be measured they play metal alarm clock, if the bar too high for the metal press inaccuracy.
* Note - Note:
Absolutely no resistance to the scale or scale current when the AC voltage measurement => If the wrong clock will fail right away!
To mistake the current scale, measured in
AC => will damage the clock
AC => will damage the clock
Resistance to the wrong scale, measured on AC power
=> Will break the resistance of the clock
=> Will break the resistance of the clock
* If the scale to measure DC voltage into AC power that they do not notice the clock, but clocks are not affected.
To scale to measure DC voltage to AC meter needle does not
however, the clock is not broken
3) How to measure DC voltage with a multimeter. however, the clock is not broken
When measuring DC voltage, we remember about thang DC transfer scale, when we set the red stick on the positive (+) source, stick to black negative (-) source, to scale higher voltage to be measured a step. For example, if we measure the voltage to 110V DC 250V DC scale, the scale case to a lower voltage to be measured => screenplay kim kim report, the case is too high to scale => kim report inaccurate.
Use a multimeter to measure DC voltage
* Where to wrong scale:
If we scale to false, but that measure voltage dc to ac scale clock, the clock will be false, false normal value greater than 2 times the actual value of DC voltage, but the clock does not is broken.
To wrong scale when measuring DC voltage => false value.
* Where to wrong scale
Note - Note: Absolutely not to mistake the clock on the current scale or scale resistance when measuring DC voltage (DC), if the wrong clock will fail soon!
Where to mistake the current scale
When measuring DC voltage => clock will fail!
When measuring DC voltage => clock will fail!
Where to wrong scale when measuring the electrical resistivity
DC => clock will fail the resistors inside!
4) How to measure electrical resistance and impedance. DC => clock will fail the resistors inside!
With the scale resistance of a multimeter that can measure many things.
- Measuring the value of the test resistor
- Measuring information check the wires of a circuit
- Check the information measure of a circuit in the circuit
- Measure the test transformer winding circuit through
- Measurement of test load capacitor discharge
- Capacitor is measured to check detectors, not been short.
- Measuring the impedance of a test circuit
- Measurement of test diodes and transistors.
4.1 - Measuring resistor:
Measure the resistance test with a multimeter
To measure the resistance of our tri perform the following steps:
- Step 1: To scale the clock back on the scale, if the resistance to small scale x1 or x10 ohm ohm, if the resistance to large scale or 10Kohm x1Kohm. => Then short the two rods to measure and adjust the clock shirt philosophy reported 0 ohm position.
- Step 2: Preparation of measurement.
- Step 3: Place the probe into two resistors, read the value on the scale, the measured value of the scale X = index scale
For example, if to scale x 100 ohm and the indicator is 27, the value is = 100 x 27 = 2700 = 2.7 K ohm ohm - Step 4: If it is too high to scale, the needle pointed up a bit, so the number will not read correctly.
- Step 5: If it is too low to scale, the needle too much, and read value is not correct.
- When resistance measurement scale was chosen so that the needle near the middle line newspaper index gives the highest accuracy.
4.2 - Use a scale to measure the test resistor capacitor
We can use the resistor ladder to check the loading and discharge of capacitor failure, as measured capacitors, ceramic capacitors if we use the scale x1K ohm or 10K ohm, if we use the convergence of x 1 ohm or x 10 ohm.
Using x 1K ohm scale to test ceramic capacitors
Measurements on ceramic capacitors to know:
- Capacitor C1 is better => free kim loaded when we measure
- Capacitor C2 detectors => on metal but not return to previous position
- Capacitor C3 has been short => clock up = 0 ohm and did not return.
Using x 10 ohm scale to test the convergence of
The above test is a measure of the convergence, convergence of rarely or short-detectors that are mostly dry (decreased capacitance) when the magnetization to know the exact damage level of convergence we need measured against a new capacitor with capacitance.
- The above is a measure of comparison of two capacitors with capacitance, the capacitor C1 is that the new capacitor also capacitor C2 is old, we find the capacitor C2 is weaker than the larger load capacitor C1 => proved dry capacitor C2 (reduced power dung)
- Note that when measuring the load capacitor discharge, we must reverse the probe several times to see the larger load.
Method 1: Use a scale line
To measure current with a multimeter, one meter in series with load consumption and noting that only the measured current is smaller than the scale value of allows, we perform the following steps
- Step 1: Set the clock on the highest scale.
- Step 2: Place rods connected to the clock load, red stick on the positive, rod-dimensional black for negative.
- If the needle on the scale less than the reduction
- If the needle on the needle, the dramatic increase scale if the scale has to scale the highest, the clock does not measure this current.
- Just press the needle will tell us that the current value.
We can measure the current through the load by measuring the pressure drop over the resistor in series with the load current limit, voltage divided by the measured values or limit line will indicate the current value, this method can measure the current greater than the ability to allow the clock and clock cumg safer.
How to read the current value and voltage as measured how?
* Read the value of AC and DC voltage
When measuring DC voltage, we read the value on the index bar DCV.A
When measuring DC voltage, we read the value on the index bar DCV.A
- If we scale 250V to read on line, we have the highest value is 250, similar to 10V, then read on the scale bar is the highest value is 10. 1000V case to scale but do not have line items for 1000, the value read on the value Max = 10 bar, the measured value is multiplied 100 times
- When measuring AC voltage, then read the same value. Read on line AC.10V, if measured on a scale of value, we calculated the rate. For example, if 250V to scale each of the 10 index number equal to 25V.
- When the current measurement, the reader reads the same value when the measured voltage value
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