6th week ( DIODE ) ...

I LOVE IT WHEN YOU SHARE EVERYTHING WITH ME :)

now,, i would like to share about the next electronic component that I had learnt on Tuesday class which is........ DIODE !!!

DO YOU KNOW WHAT IS DIODE ? :)

In electronics, a diode is a type of two-terminal electronic component with a nonlinear current–voltage characteristic. A semiconductor diode, the most common type today, is a crystalline piece of semiconductor material connected to two electrical terminals.

FUNCTION OF DIODE ?? :)

1. to allow an electric current to pass in one direction (called the diode's forward direction), while blocking current in the opposite direction (the reverse direction) .
2. diodes are used to regulate voltage (Zener diodes)
3. to protect circuits from high voltage surges (Avalanche diodes)
4. to electronically tune radio and TV receivers (varactor diodes)
5. to generate radio frequency oscillations (tunnel diodes, Gunn diodes, IMPATT diodes)
6. to produce light (light emitting diodes).
7. Tunnel diodes exhibit negative resistance, which makes them useful in some types of circuits.

these are 2 diodes that we had measured in the class :)

diode is polarised ,which means that it must be inserted into the PCB the correct way round . This is because an electric current will only flow through them in one direction (like air will only flow one way through a tyre valve) .

As we all know ,, diode have 2 connections, an ANODE and a CATHODE. The cathode is always identified by a dot , ring, or some other mark .

this is the diode that we used,, have ring to identify it as a cathode terminal

DIODE

We measured the diode given by three ways ; by physical inspection,using digital multimeter and using component analyser .

by physical inspection

From the diode given , we can easily identified the terminal of diode ,which is cathode(-ve) and anode(+ve) .

terminal that near to the ring on the diode's body is cathode terminal while the other one is anode.. easy right ? :)

by using digital multimeter

connect the diode correctly to the multimeter wire which is anode to the positive wire , while cathode to the negative wire . if wew connected it wrongly ,, multimeter did not give any value of diode because as we all know,, diode only allows current flow in one direction only .. but ,, the diode will not be damaged if we connected wrongly unless the larger voltage is supplied to the diode .

by using component analyser

i think ,, using component analyser is the most easy way to get the reading and also to determine the anode and cathode . and the most important thing to be remember by us ,, COMPONENT ANALYSER ONLY US FOR SEMICONDUCTOR COMPONENT ONLY !!

LED

A light-emitting diode (LED) is a semiconductor light source.LEDs are used as indicator lamps in many devices and are increasingly used for other lighting.It can show when the power is on , act ass a warning indicator , or be part of trendy jewelry etc. It needs to be fed from a DC supply , with the anode positive and the cathode negative .

Light-emitting diodes are used in applications as diverse as replacements for aviation lighting,automotive lighting (particularly brake lamps, turn signals and indicators) as well as in traffic signals. The advantages of LEDs mentioned above have allowed new text and video displays and sensors to be developed, while their high switching rates are also useful in advanced communications technology. Infrared LEDs are also used in the remote control units of many commercial products including televisions, DVD players, and other domestic appliances.

to determine which is cathode and anode,, we can determine by physical inspection . When we observe from the bottom of LED,,we can see side of LED which is flat. This is a cathode(-ve) terminal . While the round side is anode(+ve) terminal.

The other way is , we can see from the physical inside the LED. We can see two different size of flag . Terminal that connect with the big flag is cathode terminal,, while terminal that connect to the small flag is anode terminal ..

When LED is tested with resistor,, the LED will light up.. While,, when LED is tested directly to the voltage source ,, it will not light up .. The critical thing is,, when LED is supplied by larger voltage ,, that LED can not support,, the LED will be damaged . So,, voltage is necessary to control ,so it is suitable with the LED used .

to be continue.....see in the next entry:))