test load question

[cheech226]

i am the proud owner of one of jufran88's test loads and i've noticed with some drivers, switching the number of diodes say from 3 to 6 makes no difference in the volts i read across the resistor. i'm not sure why...

 

[Blord]

That must be a boost driver. It will boost the voltage in order to met the current setting.
The driver is capable to overcome the forward voltage of the diodes. 3 or 6 diodes makes no difference ( to the driver maximum voltage limit of course ).

 

[Fiddy]

Yes, hence the constant currentz!