Okay Hi everyone!

First off thank you for everyone making me feel welcome as I head on my way to becoming a Guru at circuits! =)

So far I have a Breadboard with this chip, It is a USB to Serial Device found here ( http://guides.machinescience.org/mod/book/view.php?id=974 ) that lets me send RAW LLC Serial out the TX and RX pins on the device and I am hooking it up directly to this device

http://www.connectone.com/media/upload/Nano_Socket_iWiFi_DS.pdf

I believe the USB to Serial is pumping 5V 500MA and I need it bring it down to 3.3V and some amount of Milliamps but I do not see it in the PDF, can any of you point out what resistor I should use to bring the V and MA down so I don't fry my chip. Thanks!

My Guess is
5V Voltage Source
3.3 diode forward voltage
250MA diode forward current (mA)

And the result I get is this..

The wizard recommends a 1W or greater 8.2 ohm resistor. The color code for 8.2 ohms is grey red gold.

Thanks for your help!!!

 

You can't use a dropping resistor if the load varies. Try a regulator instead - http://www.national.com/mpf/LM/LM2937-3.3.html#Overview

 

You can't use a dropping resistor if the load varies. Try a regulator instead - http://www.national.com/mpf/LM/LM2937-3.3.html#Overview

Does not that board/USB supply a regulated load of 5V 500ma?
I'm ready to buy one but here they have a ES and ET version, whats the difference?
http://www.national.com/mpf/LM/LM2937-3.3.html#Order

 

Does not that board/USB supply a regulated load of 5V 500ma?
I'm ready to buy one but here they have a ES and ET version, whats the difference?
http://www.national.com/mpf/LM/LM2937-3.3.html#Order

Packaging, Surface mount varietes and a TO-220 option is there for prototype work with solderless breadboard. You can click on the package name, ex. TO-263 in that list to see what the layout and dimensions are.

The ES and ET extensions are extended temperature range (-40° - +125° C) devices in the same package. The IMP versions are the standard temperature (-40° - +85°C) range.