Thanks Pico, appreciate the information. Maybe just learning towards stock for safety though...
And I've got my testing rig built, still waiting on the reusable zipties for clamping/unclamping, and my regulated lab power supply for providing constant voltage & amps, but am otherwise pretty much ready to go...
And I've got my testing rig built, still waiting on the reusable zipties for clamping/unclamping, and my regulated lab power supply for providing constant voltage & amps, but am otherwise pretty much ready to go...
Attachments
Also, does anyone know if I'll need to heat or cool the mosfets when testing at 22v and .4A to get them to 50C?
8.8W demands some cooling
easiest way is to have moderate sized heatsink, breezed with 12V fan all the time , so temp change would not mean much
clamp mosfet on heatsink, wait while reading became steady and that's it
that's - at least in my book , enough of temp. repeatability
easiest way is to have moderate sized heatsink, breezed with 12V fan all the time , so temp change would not mean much
clamp mosfet on heatsink, wait while reading became steady and that's it
that's - at least in my book , enough of temp. repeatability
Great, thanks zm. I can do both, so I should be able to just set it exactly at whatever temp I want (50C I read). I guess warm up to 50 and then keep cool once current starts flossing...
I'm finding good enough having heatsink blasted with fan
that way temp. change isn't big - mosfet is getting fast to steady readout
that way temp. change isn't big - mosfet is getting fast to steady readout
Thanks 2PD.
I saw in Nelson's resistor calculation that he's subtracting 4v for the post-resistor voltage. Should I be running up at 26v so that the MOSFET is getting a full 22v?
I saw in Nelson's resistor calculation that he's subtracting 4v for the post-resistor voltage. Should I be running up at 26v so that the MOSFET is getting a full 22v?
Not super critical, if you're close to operating conditions and they are all done in the same manner this will suffice.
If you have already tested a stack and don't want to have to start all over again, just stick with what you have, just record the testing conditions, so 12 months later you can be sure how they were tested.
It's up to you to decide.
If you have already tested a stack and don't want to have to start all over again, just stick with what you have, just record the testing conditions, so 12 months later you can be sure how they were tested.
It's up to you to decide.
Thanks. Fortunately I had another 10W 10R laying around so I was able to do 26v at the power supply and sit right at .41A. Still working out the official test, so I didn't have to retest anything and am slightly more "proper" this way. Appreciate all the help & input.
Unfortunately I haven't heard them yet, and will also have premium resistors in the circuit when I do, so I won't really be able to do a full a/b vs a traditional build...
Hi folks, everything's taken... I'll be asking for mailing addresses via pm and will ship out by the end of next week. Hope they sound great...
Due to a miscommunication, I have 6 matched Harris 9240s left (two matched trios). Anyone want them?
That's a good question.
I was linking to the wrong article, sorry. I can't find the link to the one I had in mind, so I attached it below.
Edit: Found the link too: http://www.firstwatt.com/pdf/art_mos_test.pdf
I was linking to the wrong article, sorry. I can't find the link to the one I had in mind, so I attached it below.
Edit: Found the link too: http://www.firstwatt.com/pdf/art_mos_test.pdf
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