Modern LEDs have a transparent substrate so much of the optical energy reflected from the parabolic reflector and then the distance from the 5mm lens determines the angle of the beam.
The cathode is always the substrate, so this is handy to know when both leads are cut short and may have no flat edge on case. ( also cathode mark)
So remember this.
The gold wirebond goes to the center of the Anode (+)
The reflector cup is always the Cathode (-)
I also added some other interesting factoids to my photo.
More importantly REMEMBER THIS;
- If anything can be backwards , It will be.
Always double check the datasheet and if not avail. ( bad choice) when in doubt use the diode test.
- weird example