FWIW we use several electronic loads from 300 Watts to 4 kW and they are all
MOSFET based. Maxim had an app note on an op amp based load and I wouldn't
be surprised if IR had information on paralleling MOSFETS. As an aside how
many in this group used paint can full of oil to keep a dummy load cool?

The common problem I see with a current sensing load it the initial turn on
transient. Since the power supply output is zero the MOSFETS are driven into
saturation. Depending on the response of the load and the protection in the
supply this can create some interesting problems. Crowbar protection on a 4
kW supply or a 20 kW inverter for example. The better loads allow for slew
rate control and constant resistance modes that help some.


Tom

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist