Great way to get 3.3v

MaDnEsS · Post by **MaDnEsS** » Fri Dec 02, 2005 10:00 pm

I have discovered diodes they take .6v off per 1 so if I hook 6 on then it will be down to 3.6 which is close enogh.

Post by **gannon** » Fri Dec 02, 2005 10:03 pm

actually, the voltage drop across a diode is dependent on the model it is.

Post by **Gamelver** » Fri Dec 02, 2005 11:49 pm

and you'll need a lot, because they can only handle a certain amount of current...now, using certain transistors and diodes, I'm willing to bet that a suitable 3.3V regulator could be made...I seem to remember drawing a circuit for one a while ago on a napkin...but....I used the napkin to wipe tomato sauce off my face

.....

MaDnEsS · Post by **MaDnEsS** » Sat Dec 03, 2005 10:10 am

i bout these one 7.2v 3300mah btteries on batteryspace im gonna try it on one and see if it works

MaDnEsS · Post by **MaDnEsS** » Sat Dec 03, 2005 10:52 am

can anyone give me a ms paint of the pins on the power connecter on the board

nos_slived · Post by **nos_slived** » Sat Dec 03, 2005 11:27 am

Just trace them from the PSU output...

superdeformed · Post by **superdeformed** » Sat Dec 03, 2005 12:05 pm

MaDnEsS wrote:can anyone give me a ms paint of the pins on the power connecter on the board

Have you even looked at the board? Last I checked both the 12 and 3.3v lines are labeled right next to the input pins. And also as nos_slived said, the power supply connector is labeled with 12V, 3.3V and GND.

S q u e e ! · Post by **S q u e e !** » Sat Dec 03, 2005 12:25 pm

Why spend all that money on diodes when you can get those 3.3v regulators from TI for free?

Post by **gannon** » Sat Dec 03, 2005 1:02 pm

Because IIRC those require 12V input

S q u e e ! · Post by **S q u e e !** » Sat Dec 03, 2005 1:15 pm

Actually, IIRC, they require 9

**EDIT**

Yep, the 3.3v regs require 9, as do the 5v regs, but 8v require 12.

timmeh87 · Post by **timmeh87** » Sat Dec 03, 2005 1:31 pm

both me and someone else have run the 3.3v model that "requires" 9v off of 7.2v

also.. isnt using the voltage drop across diodes the same as using a resistor? or at least a regulator. even if it works its all just wasted energy.

Post by **gannon** » Sat Dec 03, 2005 1:46 pm

S q u e e ! wrote: Yep, the 3.3v regs require 9, as do the 5v regs, but 8v require 12.

That's what I get for glancing over the page

I was going to be only using 6V for my n64, so 8V min. won't cut it

MaDnEsS · Post by **MaDnEsS** » Sat Dec 03, 2005 3:09 pm

ok i hooked it up with the diodes and it work now ive gotta charge my batteries then on to the case then on to the gcp

nos_slived · Post by **nos_slived** » Sat Dec 03, 2005 3:09 pm

If 7.2V works, 6V may too. I think 9V-15V is the effective working range, so I'm wonderring how effective those regulators really are. When I get around to setting them up, I'll start running some tests on them, but I probably won't get the chance for about a week or 2.

SNESguy · Post by **SNESguy** » Sat Dec 03, 2005 8:19 pm

also.. isnt using the voltage drop across diodes the same as using a resistor? or at least a regulator. even if it works its all just wasted energy.

No! When you use a resistor, the current will be much less coming out. (This is why resistors are used with LEDs) Ohm's law easily explains this. With a diode, the current is the same after exiting the diode. They just have a small voltage drop across them, which depends on what kind of semiconductor is in the diode. So for small precise drops in voltage, diodes are quite nice.

-SNESguy