LIGEMDIO is a gorgeous LED tester soldering kit from Boldport, for testing all sorts of LEDs, whether through-hole or surface mount.
An ideal constant current driver supplies a specific amount of current regardless of supply voltage and other environmental conditions, like temperature. The LIGEMDIO's simple circuit does this reasonably well using only two NPN bipolar transistors and two resistors. It allows the driving and testing of many types of LEDs, through-hole and surface mount.
The name LIGEMDIO is made of the first letters of Light Emitting Diode, LED.
Note: requires through-hole soldering!
LIGEMDIO was project #8 of the Boldport Club.