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RSS >  AA in parallel - plausible?
Chameleon #1 27/07/2010 - 23h02

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Registered on : 27/07/2010

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I'm designing my first 3 point cap.  Quick question.  Is there any reason I can't wire the AA batteries in parallel and use 1 ohm resistors with sfh485p's in the standard parallel layout?  It seems like I would get much more battery life out of that arrangement due to the reduction in resistor heat disappation.
(The 1 ohm figure comes from the external led calculator.)
benmeijer #2 27/07/2010 - 23h55

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Registered on : 19/07/2008

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For the SFH485p the V-forward = 1.45 V, your powersource is 1.5 V.

Theoretically you're right. The leds work while the voltage of the powersource are greater than the V-forward of the led.

But when you're using the batteries the voltage can drop below 1.5 V and than the leds have not enough voltage to light the led's.

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