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power supply voltage reduction 9v input to two 3v outputs Answered

Hello all ! I'm new to instructables and I’ve found some cool and helpful information for my projects. I need a bit of help designing a power supply voltage reduction device. One that accepts 9v input and output into two 3v 5mA outputs. I want to replace the batteries in a/b Boss selector with a more reliable source of power.

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guyfrom7up (author)2007-12-01

wait, why do you want a more "relaible source", two AA's would last way way way longer than 1 9volt battery.

lets say a 9 volt battery has a life of 500mA, 9 x 500mA= 3500wh
lets say a AA has a life of 2000mah, 1.5x2000= 3000wh

so it may appear that a 9volt has more energy but also take this into consideration:
1) a 9volt takes up the same amount of space as 2 AA's, so it's more like 6000wh.
2) the buck circuit for a 9 volt takes up extra space and is complex, or a linear regulator which is simple grossly reduces the battery life.

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Goodhart (author)2007-12-01

With a voltage divider, you would end up with a net loss and about 3.5 v on each side.

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guyfrom7up (author)2007-11-30

does it have to be exactly 3 volts? You could convert it down extremeley easy to 3.3 volts using a linear regulator

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testpartner (author)guyfrom7up2007-12-01

That a good question. :) the device that I would like to power takes 2 AAA batteries or better yet here are the specs from the owner manual: Current Draw: 5mA or less Power Supply: Dry Battery(R03 /LR03 (AAA) type ) x 2 Does this help?

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guyfrom7up (author)testpartner2007-12-01

well generally AA's when brand new prouce 1.7 volts, so that would be 3.4 volts, which I think would be fine, I'll draw you up a schematic really quick

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