DLHgn Posted October 5, 2016 Report Posted October 5, 2016 Okay, so i'm wanting to go from a 5vdc power supply to a 1.45-1.65vdc IR LED. How could I step the voltage down to match the specs of the LED? I've looked everywhere for this and haven't really found an answer to my question. I know it's probably really simple but I have no idea on how to do it. I thought of maybe just using a resistor but this has been said to be a bad idea buy a lot of people I was reading. If you're wondering i'm trying to tap into the 5v power wire from a USB connected to a webcam to also power a Infrared LED that is rated to 1.45 - 1.65 v/ 20 mA.
Krakin Posted October 5, 2016 Report Posted October 5, 2016 I have no idea why a resistor wouldn't work. Krakin's Home Dipole Project http://www.stevemeadedesigns.com/board/topic/186153-krakins-dipole-project-new-reciever-in-rockford-science/#entry2772370 Krakin, are you some sort of mad scientist? I would have replied earlier, but I was measuring the output of my amp with a yardstick . . . What you hear is not the air pressure variation in itself but what has drawn your attention in the two streams of superimposed air pressure variations at your eardrums An acoustic event has dimensions of Time, Tone, Loudness and Space Everyone learns to render the 3-dimensional localization of sound based on the individual shape of their ears, thus no formula can achieve a definite effect for every listener.
DLHgn Posted October 5, 2016 Author Report Posted October 5, 2016 Something about constant current draw and what not. I mean, if it will work then that makes my life easier.
DLHgn Posted October 5, 2016 Author Report Posted October 5, 2016 If I were to just use a resistor would I just put a 175 ohm resistor (assuming the LED is operating at 1.5v and 20 mA thus providing a resistance of 75 ohm) would that get me to my 1.5 V goal?
ShadeTreeMechanic Posted October 5, 2016 Report Posted October 5, 2016 The voltage drop across an led is .5 volts. Might as well be a dead short with no resistor. 91 C350 Centurion conversion ( Four Door One Ton Bronco) 250A Alternator (Second Alternator Coming Soon) G65 AGM Up Front / Two G31 AGM in Back Pioneer 80PRS CT Sounds AT125.2 / CT Sounds 6.5 Strato Pro component Front Stage CT Sounds AT125.2 / Lanzar Pro 8" coax w/compression horn tweeter Rear Fill FSD 5000D 1/2 ohm (SoundQubed 7k Coming Soon) Two HDS315 Four Qubes Each 34hz (Two HDC3.118 and New Box Coming Soon)
Jessica Posted October 5, 2016 Report Posted October 5, 2016 why not use a potentiometer? Rest in peace, walled 87 accord build log 03' Corolla build with AA Mayhem inside. My super random youtube channel and terrible camera work. Wiring comparison by CaptainzPlanetz Wire and fuse guide by Guest SyKo13
Ron36 Posted October 5, 2016 Report Posted October 5, 2016 Look on amazon for a step down D.C. Module they have tons of them 5v to 1.5v 2022 Ford Maverick on 22’s Skar SK1500.1 on 4 Skar VD-8’s Mids Sundown Super tweeters, Skar TX 6.5 components on Skar SKM400.4 LC2 for audio control , XS Power D680 XS Series Extra Battery
Ron36 Posted October 5, 2016 Report Posted October 5, 2016 2022 Ford Maverick on 22’s Skar SK1500.1 on 4 Skar VD-8’s Mids Sundown Super tweeters, Skar TX 6.5 components on Skar SKM400.4 LC2 for audio control , XS Power D680 XS Series Extra Battery
White Lightning Posted October 5, 2016 Report Posted October 5, 2016 why not use a potentiometer?This ... Kenwood / HELIX / Linear Power (For The Love Of Music) / Brutal Sounds / OverKill Electric Co Questions About Sound Quality ?? Try Here ... Sound Quality, What does it REALLY mean ?? SMD SOTM Winner "White Lightning" 1997 GMT400 Chevy Silverado "The Green Dickle" 1994 GMT400 Chevy "Phantom Dually" Randal's 2007 Chevy Avalanche (we haven't named this one yet) Dylan's "Brutal" 17 Chevy Cruze RS Hatch
DLHgn Posted October 5, 2016 Author Report Posted October 5, 2016 why not use a potentiometer?This ... I tried finding some that would work for me but couldn't. Probably just looking in the wrong places. Every time I found something that may work it was rated at 12v not 5v. I also need something that can be screwed in or soldered to a blank circuit board that can be screwed in. I don't want a whole bunch of loose wires and components seeing as this is for a class project and I need it to look fairly decent and thought out. My original idea was to use a pot of some sort but, like I said, I couldn't find one that was suitable. The voltage drop across an led is .5 volts. Might as well be a dead short with no resistor. I don't understand what you're trying to say.
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