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Sir Pharoan . . . . . . .
If mine olde eyes are correctly seeing the color bands of the resistor as being Blue Gray Gold Gold, then that 6.8 ohm dropping resistor and your parallel arranged 3 LEDS . . . . . along with their phospor doped overlays, suggesting of these probably being WHITE or BLUE LEDS.
With strongest suspicion of this being the light emitting cluster of a cheeeep dollar store flashlight . . . . therefore, with a WHITE LIGHT output.
( Correct me, if erring on the two first color bands of the dropping / current limiting resistor.)
If you dont have a variable voltage adjustable power supply to slowly ramp up, surely you can round up enough random D-C-AA or AAA cells to then sequentially series string them . . .one by one . . . to feed the unit .
SIMULTANEOUSLY you are monitoring the voltage across the dropping resistor and using ~ 0.408 volts as the benchmark of passed series current flow.
At that voltage level across the dropping resistor, you would have ~ 20 ma across each diode, and have approached the potential maximum voltage wanted to be applied to the units, for a resultant decent lifespan.
Lastly, there is the marked board identifier of dash 3, and just about all of these units that I have seen are using either 3 series AAA or button cells.
73's de Edd
If mine olde eyes are correctly seeing the color bands of the resistor as being Blue Gray Gold Gold, then that 6.8 ohm dropping resistor and your parallel arranged 3 LEDS . . . . . along with their phospor doped overlays, suggesting of these probably being WHITE or BLUE LEDS.
With strongest suspicion of this being the light emitting cluster of a cheeeep dollar store flashlight . . . . therefore, with a WHITE LIGHT output.
( Correct me, if erring on the two first color bands of the dropping / current limiting resistor.)
If you dont have a variable voltage adjustable power supply to slowly ramp up, surely you can round up enough random D-C-AA or AAA cells to then sequentially series string them . . .one by one . . . to feed the unit .
SIMULTANEOUSLY you are monitoring the voltage across the dropping resistor and using ~ 0.408 volts as the benchmark of passed series current flow.
At that voltage level across the dropping resistor, you would have ~ 20 ma across each diode, and have approached the potential maximum voltage wanted to be applied to the units, for a resultant decent lifespan.
Lastly, there is the marked board identifier of dash 3, and just about all of these units that I have seen are using either 3 series AAA or button cells.
73's de Edd
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