Dioda

Diodes are the simplest semiconductor components, it is composed of two (2) the cathode and anode electrodes. that serves as a tool to limit the movement of electricity, which diode only allows electricity to flow in one direction only and prevents flow in the opposite direction. (as a rectifier),
Ends of the body diode is usually given the undersigned, a bracelet or a point, which marks the location of the cathode.
When the anode potential given the positive and negative cathode, said diode be forward biased and if the contrary, is said to be a reverse biased diode. At forward bias, the difference in voltage between the cathode and the anode is called the threshold voltage or the knee voltage. Large voltage depends on the type of diode, can be 0.2V, 0.6V and so forth.
When the diodes are reverse biased (which vary depending on supply voltage voltagenya) voltage is called voltage is reversed. This reverse voltage should not exceed a certain price, this price is called the breakdown voltage, such as type 1N4001 diode sebasar 50V.
Germanium diode types such as type 1N4148 or 1N60 when given forward bias to continue the radio-frequency vibrations and when forward bias is removed, going to block the radio-frequency vibrations. The existence of these properties, diode types are used to switch.kinds of kinds of diodes and functions read


Suppliers' catalogues usually include tables of technical data for components such as LEDs. These tables contain a good deal of useful information in a compact form but they can be difficult to understand if you are not familiar with the abbreviations used. The table below shows typical technical data for some 5mm diameter round LEDs with diffused packages (plastic bodies). Only three columns are important and these are shown in bold. Please see below for explanations of the quantities. Type Colour IF max. VF typ. VF max. VR max. Luminous intensity Viewing angle Wavelength Standard Red 30mA 1.7V 2.1V 5V 5mcd @ 10mA 60° 660nm Standard Bright red 30mA 2.0V 2.5V 5V 80mcd @ 10mA 60° 625nm Standard Yellow 30mA 2.1V 2.5V 5V 32mcd @ 10mA 60° 590nm Standard Green 25mA 2.2V 2.5V 5V 32mcd @ 10mA 60° 565nm High intensity Blue 30mA 4.5V 5.5V 5V 60mcd @ 20mA 50° 430nm Super bright Red 30mA 1.85V 2.5V 5V 500mcd @ 20mA 60° 660nm Low current Red 30mA 1.7V 2.0V 5V 5mcd @ 2mA 60° 625nm IF max. Maximum forward current, forward just means with the LED connected correctly. VF typ. Typical forward voltage, VL in the LED resistor calculation. This is about 2V, except for blue and white LEDs for which it is about 4V. VF max. Maximum forward voltage. VR max. Maximum reverse voltage You can ignore this for LEDs connected the correct way round. Luminous intensity Brightness of the LED at the given current, mcd = millicandela. Viewing angle Standard LEDs have a viewing angle of 60°, others emit a narrower beam of about 30°. Wavelength The peak wavelength of the light emitted, this determines the colour of the LED. nm = nanometre.

According to the semi-conductor material used in manufacturing, there are 2 types of diodes:
1. Silicon diode: Made of silicone material.
2. Diode germanium: Made from germanium.

The types of diodes and their use:
- silicon diode: Widely used in power supply equipment as rectifier current, voltage shock safety and so on. Example: 1N4001, 1N4007, 1N5404 etc..
- Zener Diodes: Used to restrict / regulate the voltage. Example: 6.2 volt zener, 3.2 volt zener, etc..
- Diode Bridge: 4 pieces are assembled into a series diode bridge / bridge. Widely used in power supply circuit as a full wave rectifier (full wave rectifier). Example: B40C800, kiprox on motor vehicles and so on.

The diode assembly must be installed properly, should not be reversed. Physically foot cathode (K) is the foot close to sign bracelet found on her body. To find a diode is still good or has been damaged is to use AVO Meter. Position on the Ohm meter, you can forward (tap AVO + connected to the cathode and - to the anode) -> must be connected (moving needle), you can retreat -> should not be connected (the needle does not move). 'If and only if' the two criteria tsb. fulfilled all the diodes tsb. still good, but it is damaged (broken / leaking).

diode function and generally diodes can be used among others to:
1.safety
2 rectifier
3.Voltage regulator
4.Modulator
5.Controller frequency
6.Indikator
7.Switch

THE TYPES OF DIODE

Zener Diode
Zener Diode is a diode which has a nature that the reversal voltage (breakdown voltage) is very stable, this voltage is called the zener voltage. On top of the zener voltage, this diode will deliver electricity in two directions. Diodes are used as a voltage stabilizer or voltage regulator. These diodes form like ordinary diode, the difference can be seen only from the type written on bodynya and zener voltage seen at vademicum. Actually there is no difference in the basic structure of the zener, but similar to the diode. But by giving more number of doping at the junction of P and N, it turns out the diode breakdown voltage can be more quickly achieved. If the diode is usually only occurs on the voltage breakdown of hundreds of volts, the zener can occur in numbers of tens and units of volts. In the datasheet there who has a zener voltage VZ of 1.5 volts, 3.5 volts and so forth.

Diode (LED)

Another type of diode is the Light Emitting Diode (LED) that can emit light when a given forward bias. Diodes of this type are widely used as indicators and displays. For example, can be used for seven segments (display number).
Photo diode has another nature, which contrast with the LED is going to generate electric current when exposed to light. The amount of electrical current depending on the size of the incoming light. found that the electrons that hit the connection PN also release energy in the form of heat energy and light energy. LEDs are made to be more efficient if the issue of light. To mendapatkna light emission in semiconductors, doping use is the gallium, arsenic and phosphorus. Doping of different types of light produce different colors.

Calculating an LED resistor value

An LED must have a resistor connected in series to limit the current through the LED, otherwise it will burn out almost instantly.

The resistor value, R is given by:

R = (VS - VL) / I

VS = supply voltage
VL = LED voltage (usually 2V, but 4V for blue and white LEDs)
I = LED current (e.g. 10mA = 0.01A, or 20mA = 0.02A)
Make sure the LED current you choose is less than the maximum permitted and convert the current to amps (A) so the calculation will give the resistor value in ohms (ohm).
To convert mA to A divide the current in mA by 1000 because 1mA = 0.001A.

If the calculated value is not available choose the nearest standard resistor value which is greater, so that the current will be a little less than you chose. In fact you may wish to choose a greater resistor value to reduce the current (to increase battery life for example) but this will make the LED less bright.

For example
If the supply voltage VS = 9V, and you have a red LED (VL = 2V), requiring a current I = 20mA = 0.020A,
R = (9V - 2V) / 0.02A = 350ohm, so choose 390ohm (the nearest standard value which is greater).

Working out the LED resistor formula using Ohm's law
Ohm's law says that the resistance of the resistor, R = V/I, where:
V = voltage across the resistor (= VS - VL in this case)
I = the current through the resistor

So R = (VS - VL) / I

Diode bridge

diode bridge. This diode is a silicon diode which assembled into a bridge and packed into a single unitary component. In the market sold various forms of diode bridge with a variety of capacities. The size of the main bridge diodes are voltage and amperage maximum.














Photo diode

Photodioda is a diode that works based on the intensity of light, which if exposed to light so photodioda photodioda work like diodes in general, but if it does not get light then photodioda will act like a resistor with a large resistance value so that electrical current can not flow
Symbols and shapes photodioda similar to the LED, but the symbol photodioda direction of two arrows facing inwards. Photodioda widely used as a light sensor in the world of electronics, because it is sensitive to light. Photodioda used as a catcher light waves emitted by the Infrared. The amount of voltage or electrical current generated by photodioda depending on the size of the radiation emitted by infrared.

Dioda Varactor

Varactor Diodes Like most components with a wire connector, diode capacitance also has a leak which affects the work at high frequency, external capacitance is usually smaller than 1 pF. Silicon diode that utilizes the effects of the changing capacitance is called the varactor diode. In many applications replace capacitor tuned mechanically, in other words varaktor mounted parallel with the inductor is a series resonant tank. By varying the voltage on the varactor riverse we can change the resonance frequency. Application varaktor diode is usually on the tuner that tuned using a voltage.

Dioda Variable

Variable Capacitance Diodes also called varicap diode or varactor diodes. The nature of this diode is reverse direction when they are paired according to the will act as a condenser. Capacitance depends on the incoming voltage. Diodes of this type are widely used in FM modulator and also on the VCO of a PLL (Phase Lock Loop).

Dioda Schottky

Schottky Diodes Schottky diodes using metal gold, silver or platinum on one side of the junction and silicon on the light bulb (usually type-n) on the other side. Such diodes are unipolar devices because free electrons are carriers of the majority on both sides of the junction. And Schottky diode has no emptying or storage charge layer, resulting in a switch he can flame and die more quickly than in bipolar diode. As a result, these tools can menyearahkan frequencies above 300 Mhz and far above the ability of bipolar diodes.

Dioda Recovery

Step-Recovery Diodes By reducing the doping level near the junction of the plant can make the step-recovery diode devices that use charge storage. During the forward conduction diode diodes behave as usual and when dibias this diode reverse conduction while emptying layer being configured and then all of a sudden reverse flow becomes zero. In this situation as if the diode suddenly open slingshot (snaps open) such as switches, and this is why the step-recovery diode is often called a diode snap. Step-recovery diodes are used in pulse and digital circuit to produce a very rapid pulse. Snap-off that suddenly can result in switching on-off less than 1 ns. This particular diode is also used in frequency multipliers.


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