Basic Diode

1 - Semiconductor

1.1 - What is a Semiconductor?quality 
semiconductor materials to produce all kinds of semiconductors such as 
diodes, transistors, IC we have seen in electronic devices 
today.

Semiconductors are substances with characteristics intermediate between 
conductors and insulators, in terms of the semiconductor chemical 
substances that have 4 electrons in the outermost layer of atoms. That is the nature 
Germanium (Ge) and Silicium (Si)

From the initial semiconductor (pure) one must 
create two types of semiconductor semiconductor semiconductor type N and type P, then 
transplant the semiconductor pieces of N and P obtained the diode or transistor.

Si and Ge have valence 4, which is the outermost layer has four 
electron in the atom to pure Si (Ge) linked together by 
covalent links as shown below.

Pure semiconductor.

1.2 - Semiconductor type N

* When we mix a small amount of chemotherapy with 5 as phosphorus (P) on the nature 
of semiconductor silicon, a P atom linked to four Si atoms in contact 
plus the chemotherapy, only four phosphorus atoms involved electronic affiliate 
and the remaining one electron and become free electrons => Semiconductors at 
e becomes redundant (electrically negative) and are called semiconductors N ( 
Negative: negative).

 

Semiconductors N

1 .3 - P type semiconductor

In contrast, when we added a small amount of a third chemotherapy as Indium 
(In) on Si is a semiconductor material Indium atom will link 
to four Si atoms linked by covalent links and missing a 
power E => into holes (positively charged) and are 
called semiconductors P.

 

Semiconductor P

2 - Diode (diode) Semiconductors

2.1 - Adjoining P - N and Structures of the semiconductor diode.When 
there are two semiconductors are P and N, if the coupling of two semiconductors in 
a t
: At the surface of contact, excess electrons in semiconductors N diffusion 
into the semiconductor region P to fill the hole => to form a layer of ions 
electrically neutral => Ion layer constitutes the electrical domain between 
two semiconductors.

Termites exposed to P - N => Structure of diode.

* The image above is the contact connection P - N and also the structure of a semiconductor diode.

Symbol and shape of the semiconductor diode.

2.2 - Polarity upon the diode.When 
we positive voltage (+) to anode (semiconductor region P) and negative voltage (-) 
in Katot (semiconductor region N), then the interaction effect of power 
voltage, insulation narrow domain, the voltage difference between keeping the poles to reach 
0.6 V (with Si diode type) or 0.2 V (with diode type Ge) is the 
domain area decreased by no insulation => Diode arrested top conductor. If the 
voltage continues to increase the flow through the diode increases rapidly but the main 
difference between the two extreme voltage of the diode does not increase (remain at 0.6 V)

Diode (Si) polarization upon - When Dode lead 
agreement, the reduce voltage at 0.6 V

Line voltage characteristic of the diode upon

* Conclusion : When Diode (type Si) 
are polarized upon, if upon bias voltage <0.6 V is not a 
line passing through the diode, if the polarization voltage = 0.6 V, the agreement reached with the line passing through 
the diode after the current through the diode voltage drop upon increasing but remains 
at 0.6 V value.

2.3 - Diode for reverse polarity.

When the opposite polarity to the diode which is powered (+) in Katot (selling 
guide N), power (-) to anode (semiconductor P), the interaction of the voltage 
contrast, the wider domain insulation and prevent prevent electric current through 
adjacent relationship, the diode can withstand large reverse voltage 
of about 1000V, the new diode is punctured.

Diode only fires when the voltage of opposite polarity increase> = 1000V

2.4 - Measurements of Diode test

Measuring Diode test

• Set the clock in the scale x 1Ω, put two sticks on either end measuring diode, if:
• Upon measuring the anode rod black, red que Katot => kim up, turning to needles which are => good Diode
• If measured on both clockwise = 0Ω => a diode has been short.
• If the needle is not measured positively up => is broken diode.
• In measurements on the diode D1 is good, Diode D2 and D3 has been short-cuts
• If that measure 1KΩ to scale back on needles diode is still a little diode detectors.

2.5 - The application of semiconductor diode.

* Due to one-dimensional conductor diode 
is often used in the rectifier AC a 
way, the detector circuit, the circuit to reduce the polarization voltage transistor operation 
activities. the rectifier diode can be integrated into the diode bridge 
form.

Diode bridge the AC rectifier.

3 - Assorted Diode

3.1 - Zener Diode
* Structure:
Diode Zener diode has a structure similar but usually have two layers of semiconductor P 
- N paired, Zener diode is used in the mode polarization 
contrast, when polarized upon zener diode as diode often, but when distributed 
inverse zener diode will reduce the voltage to a fixed rate equal to the value 
recorded on the diode.

Shape Zener Diode (DZ)

Symbols and applications of zener diode in the circuit.

• The above diagram illustrates the application of DZ, U1 power source voltage changes, voltage stabilizer diode DZ is, R1 is to limit the line.
• We see that the source U1> DZ DZ shall always fixed on whether the source U1 changes.
• When the source changes, the counter current U1 through changes DZ, DZ efflux through a limiting value of about 30mA.
• Usually people use resources U1> 1.5 => 2 
  times more fitting term DZ and R1 lines so that the most backward through DZ 
  <30mA.

If U1 <DZ when pressure on the DZ U1 changes also change 
if U1> U1 changes when dz => constant pressure on the DZ.

3.2 - Optical Diode Thu. (Photo Diode)Diode 
Optical receiver operation mode reverse polarity, diode casing for a piece of 
glass to light in connection P - N, the diode reverse current 
proportional to the intensity of light falling on the diode.

The symbol of the Photo Diode

Illustrating the operation of the Photo Diode

3.3 - emitting diode (Diode Emiting Light: LED)diode 
developed planar diode emits polarized light when convenient, the voltage 
of the LED work about 1.7 => 2.2 V LED currents between 5mA to 
20mA

LEDs used to light source, flash design, the power status. etc. ...

 

LED light-emitting diode

3.4 - Diode varicap (variable capacity diode)Diode content is variable capacitance diode as a capacitor, and capacitance changes when we change the voltage on the diode reverse order.

Content of the variable un varicap diode (V D ) 
in the resonant circuit

• In the philosophy on when we adjust voltage VR, the voltage 
  varicap diode placed backwards changes the capacitance of the diode to change 
  => change the resonance frequency of the circuit.
• Variable capacity diode used in the channel color TV, in the circuit resonant frequency adjusted by voltage.

3.5 - Diode pulsein 
the pulse power at the output of the pulse transformer, we must use the Diode 
pulse to the rectifier. pulse diode diode is working at high frequencies of a few 
tens of KHz, normal rectifier diode can not be replaced in position 
around the diode, whereas pulse diode can substitute for position 
often diode, diode pulse value the diode is often many times higher.

Characteristics, then diode pulse shape does differ from the diode 
normally, but usually the next pulse diode marked dashed or 
marked by two rounds

The symbol of the diode pulse

3.6 - Diode detector.

Diode is a type of glass and small notebooks called diode contacts because 
the contact between two semiconductors P - N in a power point to avoid 
parasitic capacity, diode detector used in high frequency circuits used 
to separate signal wave.

3.7 - Diode rectifier.

As the diode rectifier used to face in the rectifier AC 50Hz 
, this diode is usually three types 1A, 2A and 5A.

Diode rectifier 5A