convert 12V DC to 9V DC

[asn]

If I wanted to pull power from my fans in my hood (12VDC), and convert it down to 9VDC, is there a simple and safe way to do it?

 

[pickupman66]

get a 9 volt transformer would be the most simple way. Plug that into the wall and provide a seperate 9 volt power circuit. you can also by adjustable transformers from Radio shack too.

 

[kacrocorals581]

Led dimmer switch

 

[asn]

So, the tank is a small nano, and I have 12V in the hood for the fans. I'd like to add a pot in the hood to dim the LEDs, and pull the 9-10V for the dimmer from the 12V that is already there. It is a tiny hood, and I also would prefer to not use an additoinal AC plug.

 

[ddavies564]

http://www.electronics-lab.com/articles/LM317/
Simple voltage regulator. You could use a pot but if u ever accidentally turned it up past 9 you would fry the circuitry for the dimmer. This is the proper way to do it. And the lm317 is probably the easiest ic to find anywhere radio shack should have them.

 

[AZDesertRat]

Walmart, Radios Shack, Frys Electronics, New Egg or about anywhere sells a wall wart type adjustable voltage DC power supply for between $5 and $15. I bought my two at Harbor Freight for less than $5 each but don't see them there now. They have a knob or screwdriver slot where you can set the voltage at 6, 7.5, 9, 10.5 or 12v DC. I set at 10.5-12v in summer months when I need more fan cooling and 7.5-9v in the winter to slow than fans down and reduce evaporation.

 

[Reefing Madness]

New 12 Volt DC Adjustable 9 5 14 5VDC 2 5 Amp Switching Power Supply 13 8 | eBay

 

[byee]

Would it not be simpler to have 2 adapters - a 9vdc and a 12vdc ?

Instead of the LM317, do a quick search for a switching regulator.

Hope the info helps!