Author Topic: DIY Air resistive loads?  (Read 18576 times)

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joestue

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Re: DIY Air resistive loads?
« Reply #54 on: January 17, 2017, 10:35:04 PM »
i actually used them as resistors once.

a 22mOhm mosfet is cheaper than a 22mOhm resistor in the same TO-220 heatsinkable package. the application i needed did not care about thermal coefficient, which as you know for silicon varies by an order of magnitude more than resistive heating wire.

anyhow, a zener wired from drain to gate turns them on. its up to the fet to hold down the fort at this point.

of course, negative, or positive feedback can be arranged.

Warpspeed

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Re: DIY Air resistive loads?
« Reply #55 on: January 17, 2017, 11:42:52 PM »
Don't forget about aluminium clad resistors, available from e-bay.
The Chinese ones are not now that expensive, and available rated to several hundred watts.
Main advantage is you can get pretty close to any resistance value you need, or can get even closer with series or parallel combinations.

They will need to be bolted to a suitably large flat metal plate to reduce the temperature rise, and avoid hot smells.  But its a very neat, civilized, and reliable solution.