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How to lit led using 1.2 volt small battery.....

A

Arafat Safdar

Jan 1, 1970
0
Hey can some1 tell me how can I lit LED through 1.2 volts battery.I
Connected 330 ohms resistor in series it works on 5v battery but it
doesnt work on 1.2 v battery

Regards,
ARAFAT SAFDAR
WWW.ALAGRAS.TK
trading and contracting
 
E

Eeyore

Jan 1, 1970
0
Arafat said:
Hey can some1 tell me how can I lit LED through 1.2 volts battery.I
Connected 330 ohms resistor in series it works on 5v battery but it
doesnt work on 1.2 v battery

No it won't. There's not enough forward voltage / current. You might
just get some light with a 10 ohm resistor. It'll depends on the colour
of the LED too.

But as your battery runs down, it'll soon stop glowing.

http://www.google.com/search?hl=en&...le+battery+led+inverter+schematic&btnG=Search

Graham
 
R

Rich Webb

Jan 1, 1970
0
Hey can some1 tell me how can I lit LED through 1.2 volts battery.I
Connected 330 ohms resistor in series it works on 5v battery but it
doesnt work on 1.2 v battery

Full do-it-yourself instructions at:
http://www.cappels.org/dproj/ledpage/leddrv.htm

You'll need to adjust some component values depending on the
characteristics of the LED that you're using.
 

neon

Oct 21, 2006
1,325
Joined
Oct 21, 2006
Messages
1,325
Brilliant now you have discovered that LEDS don't work on demands READ THE SPECS!!!
 
N

Nigel Heather

Jan 1, 1970
0
As a rule of thumb, an LED requires 2V across it and 10mA to light it.

So the example of 5V and 330ohm works like this

2V across the LED leaving 3V across the resistor.

3V/330 ohms = 9mA.


The problem you have is that the LED must have the correct forward voltage
otherwise it won't no matter what current you put through it.

As I said this is typically around 2V but varies a little with different
colours - but 1.2V won't be enough.

If you really want to light an LED with just a 1.2V source then you will
need to build a small switch mode step up - but this would seem to be a lot
of effort to me.

Cheers,

Nigel
 
E

Eeyore

Jan 1, 1970
0
Hi Graham, I am not well verse with computer terms, however please
help me retrieve my gmail or teach me how to use google talk.

This isn't Google Groups. You are using a (poor) interface from Google to
Usenet.

In order to do what you want you'll need to learn some basic electrical and
electronic theory - or just slavishly copy one of the many online designs that
do what you want. Someone else gave you some links.

Graham
 

neon

Oct 21, 2006
1,325
Joined
Oct 21, 2006
Messages
1,325
LOOK a LED is a diode and like all diode they follow an exponential curve vs current. the forward voltage can be 1.8v to 5v so a simple 1.2v cannot supply enough forward voltage drop to see the emission of light. 2 BAT. 1.2v depends on the LEDS it just may blow up .SO READ THE SPECIFICATION.
 
A

Arafat Safdar

Jan 1, 1970
0
Thanx Guys Appreciate your suggestions.. .. Actually i was using 1.5
volts button cell ... ..
 
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