Monday, January 24, 2011

CrazyEngineers Forum - Electrical & Electronics Engineering

CrazyEngineers Forum - Electrical & Electronics Engineering

PCB prototype manufacturer

Posted: 23 Jan 2011 05:59 PM PST

This morning I was looking for pcb prototype manufacturer and found the interesting one. The online quote is pretty simple. I think it might be useful and be another alternative for ones who looking for pcb manufacturer.

my concept on electronic devices

Posted: 23 Jan 2011 07:28 AM PST

well........
this thread is for to explain electronic devices
this is actually idea of akd,this is introduction lets start it

there are 3 types of devices
1.controlled devices
2.half controlled devices
3.uncontrolled devices
lets know about uncontrolled devices
uncontrolled devices: these devices are called as uncontrolled because they can be only start by switching on
this can be known with the examples like diodes etc...,
now time for half controlled devices
half controlled devices: these are called as half controlled because we have all the controls on on characterstics but not off the main examples are scr's,igbt's etc...,
now coming to controlled devices
controlled devices: these are devices which are controlled totally in on and off
i am not well in this examples

in my view all the electronic devices works with uncontrolled devices and all passive and active components
these half controlled devices are used in solar components and inverters

this is basic concept on these types i am interested in half controlled devices mainly scr
scr:scr is silicon controlled rectifier
this is 4 layered device the symbol is shown below

scr is having three main parts
1.gate
2.anode
3.cathode
as all know cathode and anode and there properties i am discussing about gate
gate is one of main part in scr
when we give all the voltage to scr to overcome junction2 it will be more danger to scr
so we give gate current
now coming to mode of operations
there are three states in operation mode
1.on state
2.forward blocking state and
3.reverse blocking state

on state is always clear because the name indicates that it is in on state
coming to forward blocking state
this state is the depletion layer resistance state
to overcome this state we use gate current and giving voltage to the anode and cathode
then on reverse blocking state is reversing the signs in anode and cathode panels

there is many interesting topics on scr but i am stoping here
if any more doubts or for any more concepts in this topic leave a post in electrical and electronic section i will update it


@akd: this is my personal thanks for you akd for motivating me
@CEans: if there any mistakes in my concept please help me to know because i am in the bottom of this education i need to improve a lot because i am not a professional in electronics concepts
and this post is for giving a basic concept i had in this topic

Charging mobile phones with light energy

Posted: 23 Jan 2011 04:53 AM PST

hi i am doing my third year ECE and i went through the topics/ideas for project ...thank you ,that was quite informative .. but i wanted to do something connected with light . so thought of converting the light radiated from various sources to electricity so that it can be used to charge cell phones or any other toy like thing... but i have no idea how to proceed or is it practically possible to implement such a thing ... can any one help me out plz :)
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