[CURVEDMTL]

Hey Guy's;
I am having a problem with getting a power supply for 3.3 volt dc.and figured I could use an 9 volt 500ma wal-wart for the job,but am having a problem in what is the easiest way to do this. I'm not the sharpest pencil in the box when it comes to electornics and have to ask. Using a resistor or maybe two,to cut the voltage,and what am I looking for,and can they be soldered end to end,or also a diode in making sure the voltage flows in one direction,I had searched the web and get conflicting stories about the in's and out's, but this still leaves me with dought. I know it's simple for some, but don't want to let the magic smoke out on my project. Thanks for some help In Advance.
Hank S.

[GlenniT]

A voltage resistor would be better than resistors. Batteries can peak 10x higher than rated voltage. LMT317 regulator would be fine for this, a diode is probably not required just to lower the voltage.

LMT317's costs nothing on eBay, and there are hundreds of guides that will show you how to configure it to your needs.

[Al_The_Man]

What is the current demand of the circuit? Min-Max?
If just a relatively low demand it can be done easily with a resistor a capacitor and zener diode.
You may have been advised against this because it can be inefficient, but for relatively low currents that do not vary that wildly, it works well in a pinch.
Al.

[CURVEDMTL]

Sorry for the Delay,
I have been going through my junk pile of old disgarded elect's an old APC unit i think i can salvage some resisters and diodes from and an LED for a light. I'm working on a touch probe,nothing special and thought i could use the USB from the PC and am thinking otherwise, as i don't even want to go there. The wal-wart is 9volt 500ma and i just need a good 3 volts,round about voltage,i don't think i can get a true 3 volts,so there is room for error. hooking up and what to use,or how to figure out,is the important step,as i'm not real sharp when it comes to electronics. i have been using 2 AA batt's and its costly, if you really think about it,and always a trip to the store to buy more,i figure with all the knowledge on the zone i might as well try my luck and get some help to figure out a plan form you's and your thoughts. I'm tring to keep it compact,and don't have too much room in the base of the probe to do this, but if i cut the wire,and remember the polarity,i can use the male end to plug into the female on the probe,as i need to find the mating end. I got a resister chart,and DVM and multitester for me to try and figure what i might nedd to proceed. That's where i need the help at,what to use and how to figure it,to make it work. Any help is Most Appreciated. Sorry for the Delay. Hank S.

[underthetire]

Maybe a dumb question, but why not just get a 3 volt wall wart. Old cell phone charger, maybe even a discarded 110 usb adapter.

Miniatronics Plug-In Wall Transformer, 3VDC 400mA MNTWT34 | eBay

Seems a whole lot easier to me.

[Al_The_Man]

Here is the basics for the Zener circuit.
Zener Diode Voltage Regulator - Electric Circuit
I would put a small electrolytic after the zener, around 10mfd.
Some years back I designed a 240vdc mobile generator field regulator and dropped the 240v to 12v for the logic using a zener cct. and has worked ever since.
Al.

[CURVEDMTL]

AL,

Thanks for the information. That is exactly what I have been looking for,as i have the voltage now set @3.08. Thanks also for the site,as i would never have gotten so much information on how to do this. Thanks, Hank S.