Timeline for How can I convert 5V (USB) to 3V to replace two AA batteries in series?
Current License: CC BY-SA 4.0
18 events
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| Oct 4, 2023 at 12:20 | history | edited | JRE | CC BY-SA 4.0 |
added 14 characters in body; edited title
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| Oct 4, 2023 at 12:19 | answer | added | Bas Visscher | timeline score: 1 | |
| Oct 4, 2023 at 12:00 | history | bumped | CommunityBot | This question has answers that may be good or bad; the system has marked it active so that they can be reviewed. | |
| Mar 3, 2023 at 0:48 | comment | added | Jasen Слава Україні | 120 ohm +/- 5% will be more than close enough. | |
| Mar 2, 2023 at 23:38 | answer | added | hacktastical | timeline score: 0 | |
| Mar 2, 2023 at 23:21 | history | edited | JYelton | CC BY-SA 4.0 |
deleted 22 characters in body
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| Mar 2, 2023 at 21:18 | answer | added | BiomedicalEngineeringStudent | timeline score: 0 | |
| Mar 2, 2023 at 21:02 | comment | added | BiomedicalEngineeringStudent | @Neil_UK The current is 16.33ish mA, so I will get a 2/(0.049/3) = ~122.45 Ohm resistor then. Thank you all! :) | |
| Mar 2, 2023 at 21:00 | comment | added | BiomedicalEngineeringStudent | @user253751 It is indeed 16.33ish mA, I checked with a similar LED string :) Thank you! | |
| Mar 2, 2023 at 20:53 | comment | added | Criticizing Israel not allowed | If you really want to replace batteries properly and not just guess how the circuit is, what you actually want is a voltage regulator. 3.3V regulators are plentiful and that's close enough to what 2 brand new non-rechargeable AA batteries put out. | |
| Mar 2, 2023 at 20:52 | comment | added | Criticizing Israel not allowed | An educated guess for LEDs is that 20mA is pretty darn bright (like those way too bright blue LEDs that light up the ceiling and keep you awake at night) with modern ones. They used to design on/off LEDs for 20mA, then LEDs got brighter and people still kept using the 20mA rule of thumb. You want it not so bright, decrease it down to more like 2mA. That's per LED. | |
| Mar 2, 2023 at 20:48 | comment | added | Voltage Spike♦ | Need a lot more information to answer this quesition | |
| Mar 2, 2023 at 20:47 | comment | added | BiomedicalEngineeringStudent | I do not know what the current is, can you get away with an educated guess? If yes, do you have an educated guess? Thanks for your replies!! | |
| Mar 2, 2023 at 20:47 | review | Low quality posts | |||
| Mar 2, 2023 at 23:23 | |||||
| Mar 2, 2023 at 20:45 | comment | added | Neil_UK | If you are only ever driving a fixed load like 10 LEDs, then a resistor is ideal. Compute approximate value as 2 V / load_current. If you want to drive a load that varies from use to use, then a resistor is totally the wrong thing, use a regulator. | |
| Mar 2, 2023 at 20:35 | comment | added | Jonathan S. | That depends on the current drawn by those LEDs. | |
| S Mar 2, 2023 at 20:32 | review | First questions | |||
| Mar 2, 2023 at 20:48 | |||||
| S Mar 2, 2023 at 20:32 | history | asked | BiomedicalEngineeringStudent | CC BY-SA 4.0 |