My DDL test-driver

I was bored, and had a project box laying around, so I dropped by my local RadioShack and bought the components for a DDL Driver. And, yes I did solder the connections, but I "potted" it with hot glue. The driver consists of two 10 ohm resistors, a 25 ohm pot, a switch, a 100uf cap at 35v, a diode, and a LM317 regulator. The empty hole you see is a mess-up because I mounted the switch too close to the pot, it wouldn't work, so I had to drill a hole further. So now I can have a variable driver to test my diodes with from 50mA to 250mA.
Oh, and if you have those pink post-it notes, they make a green laser dot yellow...pretty cool.


Heres the inside


Heres my messy ping-po...workstation

This is indeed a handy and useful project for testing diodes at the bench. You could add a 1 ohm resistor on the LD- connection to allow a DMM set to mV to read the diode current. If your case was a tiny bit bigger, you could have binding posts on it for all connections. You might also want to put a resistor ( 470 - 1k) across that output cap to ensure that it is drained. The output cap has killed many an LD ...

I don't need a resistor, because I can measure current through the leads, with no load. Also, can't I just short the LD+- wires with the switch off to drain the cap?