power supply load changes
power supply load changes
(OP)
Hi,
I'm testing a switching supply that's 45watts at 12 vdc. I put it on a series of power resistors to test it. Set the resistors to 3.2 ohms. After running for a while the resistors got real hot. I turned it off and checked the resistance. It had dropped to .4 ohms due to the heat. How can I set the load so that it doesn't wonder around? I can guess but there's no guarantee I'll hit the right resistance.
Thanks
I'm testing a switching supply that's 45watts at 12 vdc. I put it on a series of power resistors to test it. Set the resistors to 3.2 ohms. After running for a while the resistors got real hot. I turned it off and checked the resistance. It had dropped to .4 ohms due to the heat. How can I set the load so that it doesn't wonder around? I can guess but there's no guarantee I'll hit the right resistance.
Thanks





RE: power supply load changes
Dan - Owner
http://www.Hi-TecDesigns.com
RE: power supply load changes
The cheaper - much cheaper - alternative would be to use a larger wattage resistor attached to a suitable heatsink so that it doesn't undergo such a large rise in temperature, in which case the temperature coefficient will be of less significance. A resistance which falls as temperature increases (i.e a negative tempco) is unusual among the common resistor types. What are you using?
RE: power supply load changes
RE: power supply load changes
You'll also have extra light to work by.
Best to you,
Goober Dave
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RE: power supply load changes
Keith Cress
kcress - http://www.flaminsystems.com
RE: power supply load changes
RE: power supply load changes
Mike Halloran
Pembroke Pines, FL, USA
RE: power supply load changes
RE: power supply load changes
RE: power supply load changes
TTFN
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