Dummy Load Design Specs

[plexus]

Dummy/test loads built with different numbers of diodes, diode types and current resistor values will produce a different load on the driver. So if one person says they set the current to a certain number using one load design that number is not going to be the same for a different load design. however, there is a lot of comparison of the power output once the same LD is connected to the same type of driver. The net effect of this is comparing apples to oranges. I suppose if accuracy is not required then this is fine. I am thinking it would be a good idea for people to report their load design with their current setting, for example:

drlava microboost 555mA 5x1N5404+1ohm, 750mW peak, 706mW avg

or

drlava flexdrive v5 1.2A 6x1N4001+0.2ohm, 1345mW peak, 1102mW avg

This way we can better compare the driver settings and the power output.

What do you think?

 

[lasersbee]

Yeah... I've had a project lined up to test this on the Boost Drivers
using different combinations of test load parts...
(Haven't found the time yet)

I noticed some discrepancies in the LD current as compared to the
Test Load current on a recent Laser repair...


Jerry

 

[mojo_1234]

I'm just using simple diodes with a voltage drop of 0.7 Volts each. Just put as many diodes as required in series. It works fine for every type of laser diode I've tested so far:

• 2W 808nm Cmount - voltage drop around 2.2V - 2.5V
  
  => 3 or 4 diodes in series (2.1V - 2.8V drop)​
• 200mW 404nm - voltage drop around 4.1V - 4.3V
  
  => 6 diodes (4.2V drop)​
• 700mW 440nm - voltage drop around 4.3V - 4.6V
  
  => 6 to 7 diodes (4.2V - 4.9V drop)​

To be more precise you can also use some schottky diodes with a voltage drop around 0.2V and 0.3V.

Adding a resistor in parallel is not really necessary... and adding one in series is only recommended if you need to read the current while testing.

mo

 

[ljd10]

yes -what he said!