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Help needed with a D/C project, thanks

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Kevin Breaux

New Member
Hello everyone,

I have a project in mind and I need some tech help to make it work and save some money while doing it.

I have a wildlife game camera, it is made by Moultrie and the model is a D-40. The camera runs from (6) D cell batteries at 1.5 volts each. The camera includes a female plug for an external battery source (D/C.) The Moultrie company sells a combo 12 volt battery and solar combo that is made specifically for this model camera, but their asking price is $90.00. I am trying to figure out how I can use a 12 volt battery and drop the voltage from 12 volts to 9 volts for the camera. I have done research and found that a LM317T is rated for 9 volts D/C, but the rating on the 3-pin is 1.5 v to 37v. My question is this, if I use this LM317T on the positive side, do I need resistors also in the circuit for D/C from 12v to 9v, and if so where should they be placed?

DISCLAIMER: My education in electronics are maxed at knowing that (+) positive is red and (-) negative is black!



Well-Known Member

Your diagram refers to 2 different types of regulators the 7809 which is a fixed output of 9 volts at 1.5 amps and the LM317 which is a variable output device at 1.5 amps - this device needs 2 resistors to set the desired 9v.

In both cases just google for the manufactures data sheets which do contain simple application diagrams amongst all the guff - each device needs 2 small capacitors plus a heatsink - the size depending on how much current your camera takes.

If still unsure come back and someone will help you sort it.

PS please do not use that diagram to wire up the regulator it is totally misleading - this datasheet has good clear info http://www.electro-tech-online.com/custompdfs/2009/08/76220.pdf
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Well-Known Member
Most Helpful Member
One other consideration: What are the specs on your intended solar panel? Depending on its output current/open circuit voltage, you may need a charge-regulator between the panel and the battery, as well as the one that produces the 9V for your camera.

The battery chemistry determines the charging method. What type of battery are you planning to use?
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