Timeline for LEDs no longer bang - or whimper!
Current License: CC BY-SA 4.0
21 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Aug 4, 2018 at 22:02 | comment | added | richard1941 | Hey, oldfart, I may be older than you! In 8th grade radio and electronics class, we used to burn up 1/4 watt resistors to get that wonderful burned electronics smell. The year was 1953. | |
| Aug 1, 2018 at 4:10 | vote | accept | John Burger | ||
| Jul 30, 2018 at 20:53 | answer | added | richard1941 | timeline score: 1 | |
| Jul 26, 2018 at 12:29 | answer | added | Spehro 'speff' Pefhany | timeline score: 4 | |
| Jul 26, 2018 at 12:12 | answer | added | D.A.S. | timeline score: -1 | |
| Jul 26, 2018 at 12:05 | comment | added | D.A.S. | Beware of toxic !! Fumes | |
| Jul 26, 2018 at 12:02 | comment | added | Marco Zollinger | We used to have a batch of 5mm blue superbright (clear lens) LEDs that literally split the cap off with a bang when connected to a fresh 9V battery. Of course we did the responsible thing and built booby traps with them to scare each other. | |
| Jul 26, 2018 at 12:00 | comment | added | D.A.S. | The crappy 3mm LEDs must have started to melt the epoxy as they go towards >200’C @1W. Try better 5mm and up types for more power towards 1800’C. 9W*200’C/W | |
| Jul 26, 2018 at 7:24 | comment | added | Oldfart | I used to demo resistors. 1/4 watts of low ohms will burn nicely. Then 1/4 watt of higher resistance stays alive. | |
| Jul 26, 2018 at 7:18 | comment | added | John Burger | @Oldfart Any suggestions for an equivalent, guaranteed, safe anti-experiment? My old (10 year?) batch of LEDs were reliably POP -py | |
| Jul 26, 2018 at 7:16 | comment | added | Oldfart | Not special. I have had the same experience using a 4A regulated power supply. I could turn the voltage to 12V and "No-Pop". What was interesting, is to see that the LED gets dimmer at high voltages. I assume that is because when it gets hot, it get less efficient. | |
| Jul 26, 2018 at 6:21 | comment | added | John Burger | @bitsmack No voltage collapse. I tested a 10W, 3.3Ω resistor and measured 2.65A through it, so I think the power supply is kosher. | |
| Jul 26, 2018 at 6:09 | comment | added | bitsmack | It sure sounds like your power supply is no longer up to the task. Do you have another to try? If you measure the voltage across the LED at high current, does that voltage collapse? | |
| Jul 26, 2018 at 6:00 | history | tweeted | twitter.com/StackElectronix/status/1022361031711105024 | ||
| Jul 26, 2018 at 5:06 | comment | added | crj11 | Bad assumption on my part for power source. Interesting that it only draws 120ma with 4A available. | |
| Jul 26, 2018 at 5:05 | comment | added | John Burger | @crj11 Heh. I use a 4A 9V power brick with barrel connector - and tried putting the LED directly across the barrel! | |
| Jul 26, 2018 at 5:04 | comment | added | crj11 | Have you tried a fresh 9V battery? | |
| Jul 26, 2018 at 4:53 | comment | added | John Burger | @dim They're 3mm red LEDs, bought on special from jaycar.com.au/3mm-red-led/p/ZD1692 | |
| Jul 26, 2018 at 4:52 | comment | added | John Burger | After being "betrayed" by the LEDs from the new batch, I quickly grabbed an electrolytic capacitor - 470uF at 16V - and put it across the 9V, reversed. I don't like to do that usually; bad smells, and messy electrolyte... but it just sat there too, for 30 seconds. When I took it off the power and tested it, it tested as 469uF. Darn it! I want cheap "What not to do" lessons! | |
| Jul 26, 2018 at 4:50 | comment | added | dim | Upvoted for the dad joke. Now, what color are the LEDs? Any specs, or at least more information about them? Link from where you bought them? | |
| Jul 26, 2018 at 4:31 | history | asked | John Burger | CC BY-SA 4.0 |