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RSS > AA in parallel - plausible?

Chameleon	#1 27/07/2010 - 23h02 Top
Class : Apprenti Posts : 1 Registered on : 27/07/2010 Off line	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 Top
Class : Habitué Posts : 208 Registered on : 19/07/2008 Off line	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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