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A 20V battery can also be regulated down to 5V too. However to drop a voltage, current must be expended as heat. Inneffecient! Always try to have the smallest voltage change possible when using regulators. If you need a regulated 5V, use a 6V NiMH pack for example.
If you want to make your own switching regulator circuit, they are pretty simple circuits.
Hi,Quote from: guru on March 27, 2010, 06:24:26 AMIf you want to make your own switching regulator circuit, they are pretty simple circuits.Strange postulate here!I can assure you that even seasoned engineers sometimes give up, as they relied on jigsaw puzzle assembly instead of math (of which there's a brimfull in even a simple switcher). A total noob should stay well away and stick to the drop in replacements for linears.
Notice I first gave links to ready made switcher circuits. For 15$ I dont think you could make your own as cheap given time and money.
Every electrical system follows V=IR. In this case, the system R changes, the controller measures V, and changes C to keep V constant.
Hi,Quote from: guru on March 28, 2010, 06:59:41 AMNotice I first gave links to ready made switcher circuits. For 15$ I dont think you could make your own as cheap given time and money.Yes and they are the best option for a hobbyist.Quote from: guru on March 28, 2010, 06:59:41 AMEvery electrical system follows V=IR. In this case, the system R changes, the controller measures V, and changes C to keep V constant.That's a gross simplification when talking design of a switch mode power supply. Just the magnetics involved will give you pages (assuming pen and paper calc) of math, if you wanna do it right.Then comes endless hours of measuring and tweaking.Doubt me? Then answer this: How many µm of gap do you use and what's the permeability and dielectric constant of whatever material fills this gap.I don't think a hobbyist wanna go into this, when their main goal is making something besides a switcher.There's quite a large difference between a good design with 90% to 98% efficiency and something thrown together after a now-it-does-produce-an-output approach, which can easily be as low as 50% (or even worse than a linear supply).The drop-in replacements is the best way to go if you just want something that works.