Electronics Newbie looking to buy an AC/DC Power Supply for testing LEDs of Unknown specs..

[bklein]

Oh yeah.
Sorry, this just seems excessively silly.

[Funfinder]

Come on, this thread is totally offtopic here and giving it 5 stars instead of much !!! more better
topics shows how much goes wrong here and this must be a joke!


Its only good for two messages:

1.
Get yourself the Makro Group Racer from Istanbul if you want a real useful LED-detector!
And only if its LED is burned - which will not happen - you will have a real topic here.

2.
A simple hint because I'm still able to help persons who mess up forums with offtopic stuff:
Please simply use a high enough resistor no matter how much voltage (ok, 12 volts and below is fine)
and check out from where on the LEDs brightness no longer raises higher and leave it there.
And if you reduce 25% of the max-brightness you can save yourself alot battery power and
the LED will be virtual indestructable. At max light-power you even will need cooling-elements.

[ToddB66]

Electronics Newbie looking to buy an AC/DC Power Supply for testing LEDs of Unknown specs..

Quote:"But the above example indicates that the diameter of leds has little to no effect on the Vf"
No effect whatsoever, it's just a box the led is put in. Semiconductor physics determines Vf, it's basically the 'band-gap voltage' of the particular alloy used - gallium arsenide, gallium arsenide phosphide, gallium aluminium phosphide, silicon carbide etc etc. Infra-red ones are the lowest drop, maybe 1.6V, red, orange,yellow,green are 1.8 - 2.2V, blue and ultra-violet ones are 2.8 - 3.8V.
Just play around, have fun, learn stuff. LED's are everywhere, get hold of some junk cellphones, they have some good LED's for backlighting the display/keypad. If you can get hold of a broken LCD TV with LED backlight, you'll find loads of very high brightness white LED's along the edge of the screen.
Don't forget infra-red: slotted opto switches contain an LED and phototransistor together in a box. They are common in things like computer printers, floppy disk drives, flatbed scanners.
Ripping things to bits in general is educational. There's so much stuff discarded these days, like PC's and all their bits - HDD's, CD drives, floppy disk drives, the PSU module, cooling fans. Learning what makes things tick, and salvaging a few bits on the way, is fun. Ask around your friends and family.

Hi Skippy !

Sorry it took me so long to acknowledge your above reply ! <----Me on the right of course !

I really appreciate serious, on-topic, informative replies like this. Thanks much !

Best Regards,

ToddB66