my echo hatch photoshoot - Page 2 - Toyota Yaris Forums

HTM Yaris · 04-09-2009, 10:29 PM

All this means crap to me . Just tell me what the photon output is ...........

taKuto · 04-10-2009, 01:58 AM

Quote:

Originally Posted by PK198105

well , you want to have a constant 60mA right? Remember Ohms law V=IR right? then 12V divided by 60mA equals 200Ohms. Now for the power you can use like you said I^2R or V X I. 60mA^2 X 200Ohms = 0.72Watt

If you use an 18ohm resistor you only dropping 1.08V

200ohms is calculated for a fixed resistor burning all that current (so no LED's in that circuit, just a resistor alone). The way you can factor in LED's is that you need to subtract all the forward voltage drops and resistor handles the leftover voltage. If you want to look at it that way, assume the LED's were dropping 3.5V at 60mA (these specific ones are not dropping that exact value, but let's assume anyways).

V = 12 - 3.5 - 3.5 - 3.5 = 1.5V. This is the leftover voltage you will use a resistor to deal with. So V/I = R, 1.5V / 0.06A = 25 ohms. So 3 LED's + 25 ohms for that circuit.

Since LED's are a function of current, I usually will use an ammeter and potentiometer to dial in the desired current. China LED's don't have nice and pretty voltage to current charts to work with, and their bins are always different, so it's always a guess and check.

taKuto · 04-10-2009, 11:51 AM

The voltage drops are still pretty average for a white LED (3.4-3.8V typical), it's current that usually varies. I got the LED's off some random china supplier from ebay. 10mm 5 chip white LED's i think.

taKuto · 04-10-2009, 07:48 PM

yup, but china stuff is still much cheaper :)
only things i've been browsing on digikey are the offerings from cree. I might pickup some P4's to play with. The higher powered offerings from cree are far too expensive off digikey, i'd rather get them from china suppliers such as dealextreme.

taKuto · 04-11-2009, 03:30 AM

I was going for digital/analog hardware but changed focus to power systems

taKuto · 04-11-2009, 12:53 PM

university of toronto

Doc Zaius · 04-16-2009, 01:07 AM

Hahhaha... j/k. Whatever. Nice pics, taKuto. Nice cutoff too... *is* it a kit? Or a retro?

red_rims · 04-16-2009, 01:42 AM

sick

yaris-me · 04-16-2009, 03:14 AM

Quote:

Originally Posted by taKuto

university of toronto

mastaofdisasta · 04-16-2009, 02:32 PM

Quote:

Originally Posted by taKuto

Current is equal within one series circuit. Voltage drops on each LED. For my setup it's 3 LED's per circuit, so 60mA flows through all three LED's. Each LED gets 60mA and drop some voltage. A resistor drops the rest to maintain the current value (i believe i used 18ohms, cant remember) since the power source is a regulated 12V LM7812. These LED's are multichip, china overrates them at 100mA, so I run them at 60mA.

Man i work at radioshack and have no idea what the hell yall are talking bout

taKuto · 04-16-2009, 04:23 PM

TL projectors with philips ultinons running off hella gen 3 ballasts. OEM purple power!

mastaofdisasta, just basic circuit theory, time for you to brush up! :)

04-09-2009, 10:29 PM	#19
HTM Yaris resident senior View User's Garage Drives: 07 Yaris Join Date: Jan 2007 Location: south Carolina Posts: 814	All this means crap to me . Just tell me what the photon output is ........... __________________

04-10-2009, 11:51 AM	#21
taKuto rice rocket Drives: 05 Echo Join Date: Feb 2007 Location: Toronto Posts: 163	The voltage drops are still pretty average for a white LED (3.4-3.8V typical), it's current that usually varies. I got the LED's off some random china supplier from ebay. 10mm 5 chip white LED's i think. __________________

04-10-2009, 07:48 PM	#22
taKuto rice rocket Drives: 05 Echo Join Date: Feb 2007 Location: Toronto Posts: 163	yup, but china stuff is still much cheaper :) only things i've been browsing on digikey are the offerings from cree. I might pickup some P4's to play with. The higher powered offerings from cree are far too expensive off digikey, i'd rather get them from china suppliers such as dealextreme. __________________

04-11-2009, 03:30 AM	#23
taKuto rice rocket Drives: 05 Echo Join Date: Feb 2007 Location: Toronto Posts: 163	I was going for digital/analog hardware but changed focus to power systems __________________

04-11-2009, 12:53 PM	#24
taKuto rice rocket Drives: 05 Echo Join Date: Feb 2007 Location: Toronto Posts: 163	university of toronto __________________

04-16-2009, 01:07 AM	#25
Doc Zaius Lurker supreme! View User's Garage Drives: old and boosted! Join Date: Nov 2006 Location: Ottawa, ON, Canada Posts: 792	Hahhaha... j/k. Whatever. Nice pics, taKuto. Nice cutoff too... is it a kit? Or a retro? __________________ 2006 Red Blitzed RS 5-door

04-16-2009, 01:42 AM	#26
red_rims Black Yaris View User's Garage Drives: Black Yaris Join Date: Mar 2009 Location: CA Posts: 29	sick

04-16-2009, 04:23 PM	#29
taKuto rice rocket Drives: 05 Echo Join Date: Feb 2007 Location: Toronto Posts: 163	TL projectors with philips ultinons running off hella gen 3 ballasts. OEM purple power! mastaofdisasta, just basic circuit theory, time for you to brush up! :) __________________

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
FS: Parting out 05 echo hatch VANCOUVER	blackvitzrs	Items for Sale by private party	12	03-05-2010 11:14 AM
LF: Yaris / Vitz / Echo hatch accessories / parts!	Keej_05RS	General Yaris / Vitz Discussion	3	12-08-2008 10:43 PM
FS-2005 Toyota Echo Hatch aka "Panda Vitz" FOR SALE	3cyltrbo	Items for Sale by private party	12	08-21-2007 06:48 PM
TRD Turbo ECHo Hatch - Yaris TS	CASTREX	General Yaris / Vitz Discussion	12	04-03-2007 12:04 PM
Toyota Echo or Scion Xa/Xb for aftermarket HU receiver kit?	ceboyd	In Car Entertainment + Electronics (audio / video / alarm)	7	12-08-2006 03:13 PM