How do I reduce a 6v DC source down to 4.5v?
using ohm's law will give you the propper size resistor for your application. there is another formula that will give you the watt size of that resistor
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I would consider the amperage needed first, and not bother with resistors because they will be heating up if too much current is going through them.
Look up Fixed Voltage Regulator, in the likes of LM78xx series, with LM7805 giving you around 5V stable output. They are cheap and ubiquitous.
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There are also "Buck" regulators. Not sure why they are called Buck, but they used to be a lot cheaper. The digital readout is useful
https://tinyurl.com/2obepc66
Henry
COB Potomac & Northern
Shenandoah Valley
I'll second Henry's suggestion. For five or six dollars, you can get a buck converter that allows you to connect wires without soldering, and they're adjustable if you ever want to change to a different voltage.
York1 John
If you have just one device, figure out what it needs and use Ohm's Law to determine the needed resistance. If there's more than one device needing 4.5 volts, get a 4.5 volt supply and save yourself a lot of trouble.
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The simplest method to drop voltage would be to just install a diode(s) in series with the power line. Each diode will drop 0.7 volts. Use diodes with sufficient amperage rating for what you are drawing current wise on the line.
Mark.
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could try an LM317 adjustable regulator
greg - Philadelphia & Reading / Reading
lots of good suggestions .. diode is robably the lowest cost .. depends on what your current draw is
Look through all of your old wall warts and find one with a 4.5 VDC output, or buy one.
There are also wall warts that are variable with the flip of a switch.
I'm not endorsing this one. It was just the first that popped up in a search but it will work for you. As you can see it does 4.5 volts as well as other low voltages.
https://www.ebay.com/itm/124160879499?chn=ps&_trkparms=ispr%3D1&amdata=enc%3A1sbK-tJrsS_6MJXORA226NQ4&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&mkscid=101&itemid=124160879499&targetid=1584571731043&device=c&mktype=&googleloc=9031476&poi=&campaignid=15275224983&mkgroupid=131097072938&rlsatarget=pla-1584571731043&abcId=9300697&merchantid=116326461&gclid=CjwKCAjw_MqgBhAGEiwAnYOAer5uAk6gddCBNUQuL27dB1BKy0Wo3dF0nu1o90Pp2heGMJ5qbqqNBxoCoDcQAvD_BwE
mkepler954 How do I reduce a 6v DC source down to 4.5v?
As mentioned, there are a lotof ways to do it. Which is best will be determined by what you are powering and how stable you 6 volt source is.
I found several dimmers in my spares box and hooked them up. Worked perfectly!
Thanks for all your suggestions.