I have an unknown LED, I think it was previously run off of ~14vDC.
I want to repower it - I have a 5vDC 3A power supply.
I dont know the LED rating so I've rigged it up to a simple series circuit.
6v cell >>>> 1k R >>>> LED >>>> cell
This gave 5.95v at the cell, and 5.55v across the LED suggesting a 6A LED forward current.
6v cell >>>> 10k R >>>> LED >>>> cell
I retested again with a 10k R which gave 3.77v across the LED again implying a 6A LED forward current.
1) does this make sense / is this right? Most LEDs I see have forward currents in mA not A.
2) can I run this 6A LED off my 5v3A supply long term without damage / excessive load?
3) what would be the best series resistor value?
Unfortunately changing the LED is not simple.