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LM317 could power an 8V, 90mA mini camera?

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Newbie level 3
May 18, 2008
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Good day!

Need some help from you guys. I was wondering if the LM317 (as simple as possibel) could power an 8V, 90mA mini camera? I was intending to use a 7.2/7.4V battery to power it. Since the source is less than the required input voltage, would the LM317 be able to step up the voltage to meet the loads requirement?

Appreciate any help you guys can provide. Thanks!

Question on the LM317

The LM317 is a "buck regulator" which mean it can only reduce the input voltage to a lower level. It cannot increase 7.2V to 8V. For that you'll need a boost regulator or DC-to-DC converter.

Re: Question on the LM317

No, it will be useless.
Maybe you do not need any voltage regulator because your camera can work flawlessly even with a smaller input voltage.
If you give us the camera model/manufacturer MAYBE we can give you a more detailed answer.

Question on the LM317

It's the Mini Wireless Camera Kit, brand name is Shepherd.

@APBeck3: So If I use regular 9V battery as the input source of the LM317, am I correct to assume it will work? Thanks.

@bepobalote: Won't there be any issues with it's operation? Though the voltage difference is very small.

Really appreciate the help guys.

Re: Question on the LM317

If it is the camera I think, you will have no problems to let it work with 7.2V
If you have a variable voltage power supply, you can try to use your camera with 8V and start to reduce its voltage until your camera stops working: make a note and add about 10-15% to this voltage. This can be considered the minimum working voltage.
The only problem is that the output power of the transmitter will be lower than with the default 8V: depending on your requirements this can be a problem or not.

Don't worry: the chances to ruin your camera are nil!!
Not the same if you power it with a higher voltage!

Question on the LM317

Thanks! I'll give it a go.

A 9V battery voltage drops quickly to 7V then drops slower to 5V.
But an LM317 regulator needs an input of at least 10V for an 8V output.

@Audioguru: Thanks for the input, will definitely consider this.

If anybody here has a schematic or circuit I may build myself that could provide two different voltages (7.2V, and 8V) from the same source, preferably from a single battery no greater than 11.1V, I'd be grateful!

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