How to make a 9volt Battery to output only 5-6volts???

Greg Boston · April 5th, 2005, 12:50 AM

Shannon,

I think these good folks were suggesting that you add an additional switch to disconnect the battery when not in use. Stick with the 5volt regulator, that is the easiest solution given your original specificatons.

-gb-

Kyle Ringin · April 5th, 2005, 01:01 AM

Shannon, hope we've helped, and not just complicated things...

a LM317 is a regulator that is fundamentally a 1.25v (IIRC) regulator. It is labelled an 'adjustable' regulator in that it is designed to have the adj pin not directly connected to 0v, but biased by a resistor network, either discreet resistors or a pot to achieve any voltage between 1.25v and 37v (depending on input voltage). Short answer is it needs more components to work than a 78xx series regulator - not necessary.

That said, 78xx regulators can be made to regulate to higher than their rated voltage by adding the resistor network as well but aren't so flexible.

Discreet components are the 'normal' components. A resistor is a resistor, a capacitor a capacitor. They are the ones you'd find in radio shack or whatever. They are not an integrated circuit such as a regulator, processor, etc that is a combination of tens or millions of transistors, resistors, etc all in the one package.

April 5th, 2005, 12:50 AM	#16
Greg Boston Wrangler Join Date: Oct 2003 Location: DFW area, TX Posts: 6,117 Images: 1	Shannon, I think these good folks were suggesting that you add an additional switch to disconnect the battery when not in use. Stick with the 5volt regulator, that is the easiest solution given your original specificatons. -gb-

April 5th, 2005, 01:01 AM	#17
Kyle Ringin Major Player Join Date: Oct 2004 Location: Melbourne, Australia Posts: 241	Shannon, hope we've helped, and not just complicated things... a LM317 is a regulator that is fundamentally a 1.25v (IIRC) regulator. It is labelled an 'adjustable' regulator in that it is designed to have the adj pin not directly connected to 0v, but biased by a resistor network, either discreet resistors or a pot to achieve any voltage between 1.25v and 37v (depending on input voltage). Short answer is it needs more components to work than a 78xx series regulator - not necessary. That said, 78xx regulators can be made to regulate to higher than their rated voltage by adding the resistor network as well but aren't so flexible. Discreet components are the 'normal' components. A resistor is a resistor, a capacitor a capacitor. They are the ones you'd find in radio shack or whatever. They are not an integrated circuit such as a regulator, processor, etc that is a combination of tens or millions of transistors, resistors, etc all in the one package.