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Sunday, 25 June 2017

What is SMD Diode - English

What is SMD Diode - English 

diode only blocks current in the reverse direction while the reverse voltage is within a limited range otherwise reverse barrier breaks and the voltage at which this breakdown occurs is called reverse breakdown voltage. 

The diode acts as a valve in the electronic and electrical circuit. A P-N junction is the simplest form of the diode which behaves as ideally short circuit when it is in forward biased and behaves as ideally open circuit when it is in the reverse biased. 

Beside simple PN junction diodes, there are different types of diodes although the fundamental principles are more or less same. So a particular arrangement of diodes can convert AC to pulsating DC, and hence, it is sometimes also called as a rectifier

Symbol of Diode

The symbol of a diode is shown below, the arrowhead points in the direction of conventional current flow.

We can create a simple PN junction diode by doping donor impurity in one portion and acceptor impurity in other portion of silicon or germanium crystal block. 

These make a p n junction at the middle part of the block beside which one portion is p-type (doped with trivalent or acceptor impurity), and another portion is n-type (doped with pentavalent or donor impurity). 

It can also be formed by joining a p-type (intrinsic semiconductor doped with a trivalent impurity) and n-type semiconductor (intrinsic semiconductor doped with a pentavalent impurity) together with a special fabrication technique such that a p-n junction is formed. 

Hence, it is a device with two elements, the p-type forms anode and the n-type forms the cathode. These terminals are brought out to make the external connections.

Types of Diode

The types of diode are as follow

  • P-N junction diode

  • LED  (light-emitting diode)
A light-emitting diode (LED) is a semiconductor device that emits visible light when an electric current passes through it. The light is not particularly bright, but in most LEDs it is monochromatic, occurring at a single wavelength. The output from an LED can range from red (at a wavelength of approximately 700 nanometers) to blue-violet (about 400 nanometers). Some LEDs emit infrared (IR) energy (830 nanometers or longer); such a device is known as an infrared-emitting diode (IRED).

  •  Zenor Diode  जेनर डायोड – फिक्स वोल्टेज के होते है l चार्जिंग सेक्शन में लगे होते है 

चार्जिंग डायोड़ ( Zener Diode ) – चार्जिंग डायोड़ को प्रोटेक्शन डायोड़ भी कहते है चार्जिंग डायोड़ 6 वोल्ट से अधिक आगे नही जाने देता है चार्जिंग डायोड़ की वोल्ट क्षमता 4V, 6V  8V तक Fix होती है ।

यदि चार्जर खराब हो जाये तो चार्जिंग वोल्ट अधिक सप्लाइ देगा लेकिन चार्जिंग डायोड़ लगा होने से IC व मोबाइल के पार्टस को करेन्ट 6 वोल्ट ही जायेगा । चार्जिंग डायोड़ काले कलर का होता है जिसकी एक तरफ टाँग लम्बी और दुसरी तरफ छोटी होती है । छोटी टाँग + की होती है 

चार्जिंग डायोड़ को मल्टीमीटर से चैक करना -

काली व लाल लीड को क्रमशबड़ी व छोटी टाँग पर रखे, एक तरफ नंबर दिखाने व दुसरी तरफ नही दिखाने पर सही होता है ।

विशेष – इसमें + व – होता है इसलिये लगाते व हटाते समय ध्यान रखे कि + वाला भाग किस तरफ है ।

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