LED Tester with discrete constant current sink

This video shows you how to build a LED tester that consists of six separate constant current sinks (in the video I call them current sources, this is wrong). The current sinks are built discretely by use of two general purpose NPN transistors (BC548 or 2N3904) and two resistors. Schematic is included and is really easy to build yourself.
Music by www.LukHash.com
Video License: CC BY-SA 3.0

[@ciprianwinerElectronicManiac]

Very nice project. Thanks for sharing. I have a better idea in my view which is an adjustable constant current source, this allows it to be more flexible and compact.