is it enable reduce 12v to 1.5v?

[]\[ickless]

Wow! Seem tat u guys got advance technical knowledge in electrical/electronic. Salute! :D

Actuall i'm oso thinking & wondering of how can i extract 4.5v from the 12v source, without adding any electronics component such as resistor.. bla.. bla.. etc.

Bare in mind, i just keep wondering if only i can simply tap a wire from a room clock, directly connect to the led stuff.. (i'm talking 'bout room clock for a car :P)

Can tat be done? What's the voltage applied to the room clock actually? Or can it be done if i simply tap a wire from a lower voltage stuff such as room light/meter light/ignition key light etc.. :blink:

Any sifu mind to give a suggest/comment on this?

 

[JUN]

like this ka? this one is lix punya pic. anything pls refer to him for more info...

Regards;

 

[JUN]

another one...

Regards;

 

[cipan_supercas]

if u don't understand automotive electrics/electronics, i suggest u better ask somebody who have the knowledge to help u do it.
not only the little project of yours can go up in smoke, but maybe ur whole car can be smoked or even catch fire. This is not a something that u can do by trial and error if u understand nothing about electronics.
I'm not trying to teach or boasting myself that i knew everything, but i have vast knowledge and experience.
My advise is : Don't monkey with anything u don't understand.

 

[acbc]

Originally posted by sam1741@Mar 15 2005, 08:46
i think..
cannot use resistor alone

cause the voltage and amp is different
when car idle and moving..

better use regulator.. easy to made only..

7805 is for 5v one

LM2937 one i think got 3v one.. (not sure)


if i not mistaken 78xx series regulator
can tolerance up to 30v
so no need to worried about input voltage..


but remember to supply your regulator with a heatsink

I think you can because many LEDs from alarm, wiper nozzle and bulbs used resistors.

Ok, I have a project which involves Super Bright white LEDs but I need to step the voltage to 4.5V. Anyone can help? :huh:

 

[kruger]

Ok, I have a project which involves Super Bright white LEDs but I need to step the voltage to 4.5V. Anyone can help? :huh:

[snapback]820129[/snapback]​

better if some of the electrical and electronic sifus out there can show a schematic la... still blur... :huh:

 

[xtorm]

hmmm if i wan to fully utilize the 12 can ahh? connect 4 led in series can hh?, assuming all led same n can take up to 3v

 

[kruger]

Originally posted by xtorm@Mar 22 2005, 01:29
hmmm if i wan to fully utilize the 12 can ahh? connect 4 led in series can hh?, assuming all led same n can take up to 3v

[snapback]829071[/snapback]​

me also hmmm.... :lol:

 

[khguan]

Originally posted by xtorm@Mar 22 2005, 01:29
hmmm if i wan to fully utilize the 12 can ahh? connect 4 led in series can hh?, assuming all led same n can take up to 3v

[snapback]829071[/snapback]​

can... but if one of de LEDs is burnt.. then de all of it will not light up.. well LED wun burnt dat easily lar.. provided de voltage is not overloaded. B)

 

[xtorm]

hehe..i got led runing at 5v also ok wat..........:)

 

[khguan]

ok wan.. it will be very bright... but i think de lifespan will be shorter lor...

n it will slowly get dimmer over time with de same amount of voltage supplied to de LED..

B)

 

[n305er]

I connect directly to 12 Volts... 5 LED in series...

 

[xtorm]

bright or notlahhh?

 

[cmos]

I agree with votech. Go with IC voltage regulators. The LM78* series should suffice and comes in a wide range of voltage outputs.

IC Voltage Regulator

You can google out the schematics for these but it'll probably involve less components than you can count on 1 hand.

Enjoy ;)

 

[kruger]

Originally posted by cmos@Mar 28 2005, 10:34
I agree with votech. Go with IC voltage regulators. The LM78* series should suffice and comes in a wide range of voltage outputs.

IC Voltage Regulator

You can google out the schematics for these but it'll probably involve less components than you can count on 1 hand.

Enjoy ;)

[snapback]846204[/snapback]​

if i post my schematic of that psu unit, can you guys give comments and maybe fix it... :)

 

[kruger]

well... here is the schematic... any comments or upgrade or anything? :rolleyes:

 

[khguan]

dats a very common circuit used in DC power supplies...

always c this circuit back to de time when i was an electronic hobbyist..

for normal n low ampere use... no need to upgrade anything lar..

 

[votech]

The Regulator in the schematic only allow u to drive 12V load up to 1A of current. if you need more...gotta use another series or another way is to connect in parallel... ;)

 

[khguan]

yep.. dats rite... u may need a heatsink for it if u r using constant load