Making Twelve Volts Three

[laserpyro]

Basically My Spiro Project uses 12vdc i need to transform it to 3vdc for the laser.
thanks
Laser - Pyro

 

[john_lawson]

heres a diagram for a build for a 12v -to 3v

http://www.coolcircuit.com/circuit/12v_to_3V/

 

[laserpyro]

thanks alot john
but what are the parts i need for this
theres no parts list on the site
sorry if i sound like an idiot

 

[ndrew2505]

the parts list is in the picture...

http://www.coolcircuit.com/circuit/12v_to_3V/12V_to_3V.GIF

 

[john_lawson]

oops yea thanks Drew lol

 

[laserpyro]

ok thanks alot guys

 

[phoenix77]

Here's a better, quicker, cheaper way, that doesn't require ANY parts. In fact, you'll have parts left over. You say you need to drop 12VDC, down to 3VDC, correct ??

12VDC divided by 1.5VDC batteries = 8 batteries. In order to get 3VDC, just remove 6 of the batteries, which will leave you with 2 batteries. 2 batteries @ 1.5VDC each = 3VDC Simple as pie & you have 6 batteries left over, & didn't have to spend a cent. Well, it looks good on paper anyway. LOL.............rob

 

[laserpyro]

thats all well and good pheonix except i have 3 12volt computer fans running parallel

 

[digital_blue]

You could just use a linear regulator such as the LD1117v33. Just feed 12 volts into it and out comes 3.3 volts.

 

[phoenix77]

Laserpyro, 'twas only a joke buddy. Just tryin' to inject a bit of levity into this posting, LOL, Ha-HA- HA................rob

 

[Cyparagon]

Use a voltage divider. A pot will allow you to fine-tune the voltage, or you can just use two resistors, with one value being thrice the value of the other. I recommend 3kohms for R1 and 1kohms for R2.

 

[rog8811]

If your laser is a greenie you could do what I did in my liquid sky.
I just purchased a 12v to 3v adaptor from ebay Something like this....
New 12V in car DC voltage regulated adaptor converter on eBay (end time 14-Sep-09 11:34:28 BST)
The one I found was wire in and wire out rather than plug in, have a look around on the bay, they can be very cheap.

Regards rog8811

 

[lasersbee]

You didn't say if you have a wall plugged 12vdc power Supply..
or a re using 8pc 1.5Vdc Batteries...

If you are using 8 batteries I have a cheap solution and you can
still use 8 batteries for the fans...

If you are using a single 12vdc Battery ot a 12vdc Wall powered
PS then I would go with Rog's idea...


Jerry

 

[HIMNL9]

Also, thse cheap usb chargers or cellphone chargersfor mp3 for use in cars, with lighter plug ..... usb ones are 5V output, but is easy to adapt them to 3V, cellphone chargers are usually already 3,7V

 

[billg519]

Depending on current required at 3V, you could use 1117 3.3 as mentioned, or use LM317 (1.5A), or LM350 (for up to 3.0A). Heatsink it well, you should have room in a spiro, linear regulators turn excess voltage into heat ... Schematics available online and are also in the datasheet for the regulator.

 

[Cyparagon]

The one I found was wire in and wire out rather than plug in, have a look around on the bay, they can be very cheap.

Regards rog8811

Cheaper than the two resistors required to make a voltage divider? Two words:

Occam's razor.