## A quick question!

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• Its time for a quickie! I have a 6V, 200mA transformer, and i want to power six highintensity UV LEDS with it, the problem is Ill need a resistor of som sorts
Message 1 of 5 , Nov 30, 2004
Its time for a quickie!

I have a 6V, 200mA transformer, and i want to power six highintensity
UV LEDS with it, the problem is Ill need a resistor of som sorts so
that I dont burn the leds up (5\$ a piece!) Do you think 200 ohms is
ok, or should I go higher? Or even lower?

/Erik
• ... Do a google search for led resistor calculator and plug the values into one of those. Also, if you re using just one resistor for all the leds, remember
Message 2 of 5 , Nov 30, 2004
--- In beam@yahoogroups.com, "Erik" <firecrow@t...> wrote:
> Do you think 200 ohms is
> ok, or should I go higher? Or even lower?

Do a google search for "led resistor calculator" and plug the values
into one of those.
Also, if you're using just one resistor for all the leds, remember
that 6x 30mA 4.5V LEDs = 800mW, so you want a 1 Watt resistor. It
might be easier to put an individual resistor on each led, that way
you can use the normal 1/4 watt ones.
• ... way ... Oops, ignore this part, 800mW dissipated through the LEDs doesn t mean 800mW dissapated through the resistor.
Message 3 of 5 , Nov 30, 2004
--- In beam@yahoogroups.com, "Justin" <archvillain@e...> wrote:
>
> Also, if you're using just one resistor for all the leds, remember
> that 6x 30mA 4.5V LEDs = 800mW, so you want a 1 Watt resistor. It
> might be easier to put an individual resistor on each led, that
way
> you can use the normal 1/4 watt ones.

Oops, ignore this part, 800mW dissipated through the LEDs doesn't
mean 800mW dissapated through the resistor.
• Carefull about using only one resistor for all the LEDs in a circuit. As more LED s are lit, the overall brightness of each will drop. Or inversely, as each
Message 4 of 5 , Dec 1, 2004
Carefull about using only one resistor for all the LEDs in a circuit.
As more LED's are lit, the overall brightness of each will drop. Or inversely, as each LED is no longer lit the brightness of the other (lit) LED'd will increase.
It should work fine for a circuit where only one or two are lit at one time, but if several LED's are used (with overlapping "Lit" times) there could be some problems

DrewB

Justin <archvillain@...> wrote:

--- In beam@yahoogroups.com, "Justin" <archvillain@e...> wrote:
>
> Also, if you're using just one resistor for all the leds, remember
> that 6x 30mA 4.5V LEDs = 800mW, so you want a 1 Watt resistor. It
> might be easier to put an individual resistor on each led, that
way
> you can use the normal 1/4 watt ones.

Oops, ignore this part, 800mW dissipated through the LEDs doesn't
mean 800mW dissapated through the resistor.

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• Thanks for all the input, the google search provided most of what i needed, 200 ohm should set things right. ... highintensity
Message 5 of 5 , Dec 1, 2004
Thanks for all the input, the google search provided most of what i
needed, 200 ohm should set things right.

--- In beam@yahoogroups.com, "Erik" <firecrow@t...> wrote:
>
> Its time for a quickie!
>
> I have a 6V, 200mA transformer, and i want to power six
highintensity
> UV LEDS with it, the problem is Ill need a resistor of som sorts so
> that I dont burn the leds up (5\$ a piece!) Do you think 200 ohms is
> ok, or should I go higher? Or even lower?
>