So sorry..

Hey guys...
Dalilah here..
So sorry for not updating this science blog again..
Been busy lately..
Wondering what Nadia's doing??
hm...

So sorry...
Did not meant it to happen..

If either of us are free, we'll update alrites!! =)

Have a good night everyone..! ^_^||

Yo!
Dalilah here...
So sorry for not updating more !!!

Erm..
So, i 'm currently studying in electronics and i'm taking another 2 more module which is: CAD and DE..
Digital Electronics.

I know it's been long but hey, i'm busy..
I have to catch lots of things up..
Cos i'm kinda blurry..
hehe...

Ok..Ok...
Update here first ok..

What I Currently Do In ITE ???

Hey, everyone... Nadia here and it's my first time updating this blog as I'm mostly busy that I even forget updating.
So as mention in the previous blog I'm currently taking up Visual Communicaions in ITE College Central (Tampines). So, basically for my first year, for the pass 6 months I'm studying 2 modules - Drawing & Photoshop.
At the start of the semester I was struggling though with my proportion but managed to improve.

In my course for drawing we learnt on how to draw : still life, potrait, animals, urban movement and there's another 2 I've forgotten. So for my coursenote there are 36 chapters all together & for Photoshop we learn on editing, making envelops etc.

**I'll be you guys through a lil' on what I learnt.**

For my Design Principals, I learn on what mode are used for what printout - advantages & disadvantages.

• RGB mode : The disadvantages of working in RGB mode (for print), is that RGB allows a greater gamut - scale/range of colours than what you can print.
• CMYK mode : To place a colour image in a page layout appliction from where it will br colour seperated, and need to convert from RGB to CMYK and Photoshop to adjust any colour in the RGB image.

• DIRECTORIES :  Yahoo!, Yahooligans, KidsClick!, SurfMonkey & Awesome Library.
• SEARCH ENGINES :  HotBot, Alta Vista & Google

So that's all I got to go.. Will update more if have ime and have to stop here !!!
Till then.

*Nadeeya signing out....* <3<3<3

Topic 6- SMT

A surface mount component can be defined as any electrical components mounted on one or both sides of a PCB and interconnected to the copper tracks via a lap solder joint.
* Advantages: Smaller and lighter, higher quality assembles, lower overall costs.
*There are 3 different types of SM components.
1) Metal electrode face resistor diode
2) Small Outline transistors> 23(SOT) and 89(SOT)
3) Small Outline Integrated Circuits (SOIC) >Gull wing. J-Bend and I-Bend 
4_ IC(Memory devices)
5) Plastic Leaded Chip carriers
6) Lead-less Ceramic Chip Carriers(LCCC)
*6) is a method of mounting chips on boards using contacts instead of leg-like pins. The chip rests in a socket that has contacts on its base for completing the connections.

Static Electricity

*Objects are charged by adding or removing electrons
*Static charges are produced whenever there is friction between 2 materials or between human and material.
*Electrostatic discharge is a sudden discharge of stored up of static charges.
*It can cause rupture on materials inside devices.
*ESD devices can be damaged when in contact with skin.

Field Effect Transistor

*Semiconductor devices that control the flow of the current by an electric field.
* FETs are voltage operated device, and does not require input current.
* It has extremely high input impedance.

JFET-Junction Field Effect Transistor

* Available only as depletion mode type
* Insulated Gate type(IGFE9) 
(available as enhancement mode or depletion mode)
(metal oxide semiconductor (FET MOSFET))
(silicon-on- sapphire FET)
(Can be N-channel or P-Channel)

Inductor

*Made up of a coil of wire wound around a core.
*Tend to oppose the change of current flowing throughout.
*Also known as inductance
* Unit is Henry(H)
*Types of inductor: Air, Ferrite, Magnetic Dust and laminated iron
*Known as chokes or coils.
*It is to block noise or act as a filter.


Okay, let's stop for awhile now shall we?
This is the whole 2 pages.
I'm afraid there's 3 more to go..
So sorry.. Made a mistake ...
=)
Happy Reading / revising!
^_^||

Another one but the same topic...

Ok. So this is another one. And it's under the same topic. But i written it on the other pages..
So here it is:

Topic: PN Junction Diodes = Fundamentals of Semiconductors

'N' type semiconductor- Antimony
'P' type semiconductor - Gallium
*Electrons on the outmost shell known as valence electrons
* Arsenic is a pentavalent impurities
* For a 'p' type semiconductor the majority carriers are holes
* The process of adding controlled amount of impurities to a pure semiconductor to improve conductivity is called "Doping".
*Intrinsic semiconductors do not contain any impurities.
* Valence electrons are electrons found in the outermost shell
*ION is positively charged.
*Forward bias of an PN junction diode = the potential of the external supply forces will make holes and electrons to cross the junction.
*Diode forward characteristic curve = the forward bias resistance of the diode is very low.
* Reverse bias = the external voltage supply causes the majority carriers to move away from the junction.
* The reverse bias resistance of the diode is very high.
* The Peak Inverse Voltage is the maximum reverse voltage a diode can handle.

Diode Forward Bias Characteristic Curve and Reverse

* Break Down voltage

* For any diode, the Peak Inverse Voltage (PIV) is the maximum safe reverse voltage of a diode specified by the manufacturer .

Characteristics of a diode

* When the diode is forward biased ,  it act as a closed switch in series with a small forward voltage(0.7v).

Full-Wave Bridge Rectifier

*Requires a non-center tapped transformer and 4 diodes.

Current Relationship in a transistor

* The base current IB is very small but very important.

*Current gain= a= IC/IE

*Current gain, beta = B= IC/IB

Transistor as a switch

*Saturation - closed switch

*In saturation, base -emitter junction is forward biased and collector base junction is reverse biased.

*Large IB causes IC to reach its saturation value.

*Cut off - Open switch

*Base emitter junction is not forward-biased.

*All currents are zero.

*VCE = VCC

Safety precautions!

Important!

*Use IONIZERS to reduce charges.

*STORE and transport sensitive devices in ESD protection packaging

* Use treated plastics.

Whatever i've learnt foor these past few months - dalilah

Hey..
So as promised..
Here it is..
But this is based on what i've written on my notepads ..
So here it goes:
This is based on what i revised too..

PN Junction Topic 8
* A diode consists of a PN junctions
* When a diode is forward biased,its forward resistance becomes very low.
*When a diode is reverse biased, current cannot flow through it because it has a very high resistance.
* The most widely used semiconductor material in electronic devices is silicons.
* A PN junction diode is used as a rectifier to convert ac current to dc current.
* The process of removing half the input of an sinusoidal signal through a diode to generate a dc level is known as half wave rectification.
*The bridge rectifier output produces a/an full wave pulsating waveform.
* Capacitor is an electronic components that is used to reduce ripple voltage in RC filter circuit.
*Zener diode is commonly used as a voltage regulator.
* A zener diode is reverse biased. When the reverse voltage reaches the breakdown voltage, its voltage will remain constant.
*The device that is used to clean the dust particles of air to prevent electrostatic discharge is known as ionizer.
*To discharge the ESD from the human body is by using a wrist-strap tied to earth or ground terminal.
*When a transistor is used as an open switch , it operates in the cut-off state or region.
* When a transistor is used as a closed switch , it operates in the saturation state or region.
* To turn on a silicon transistor , the VBE required is 0.7 V.
* To correctly bias a transistor as an amplifier , the emitter-base must be forward biased and the collector-base must be reverse biased.
Okay...
That's all for now...
Will update soon again..
But this is just part one of the notes... There's another 3 more pages to go..
=)
Have fun reading or going through it..

Hello

Hello!!
Sorry sorry...
Been trying to keep this blog alive!!
Well..

Dalilah here!!
I'm currently studying in electronics in ITE college East
And Farah is studying in Visual communications...in ITE Central..
So, i guess, i 'll be the one who will keep this blog alive.
Yikes!
Okays.
If i have enough time, i'll update whatever i learnt here ok..
So i've been planning to put tag boards and such but we'll see..
Ok..
Enough talks and have a nice day!