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What resistor do I need to drop 9 volts to 4.5 or 5? Answered

I need to use a resistor (not a voltage regulator, sorry) to drop 9 volts from a battery down to 4.5 or 5. I am running an attiny85, which is also used to power up to 3 30ma leds. What do I need to use?

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mrmerino (author)2013-04-05

Dude, do yourself a favor and get a voltage regulator.

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steveastrouk (author)2013-04-03
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XOIIO (author)steveastrouk2013-04-03

I'm constrained for room, and I have no more breadboard real estate, so I'll just wait.

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iceng (author)XOIIO2013-04-03

Yes.... let the breadboard grow over night :)

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steveastrouk (author)2013-04-03

Won't work. The load, and therefore the voltage will vary too much. Stick 4 diodes in series if you need to drop 4 volts.

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XOIIO (author)steveastrouk2013-04-03

Damn, guess I'll have to try and use a voltage regulator then, Ittl have to wait till tomorrow unfortunately.

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