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I have some DC-DC power supplies that I would like to test. (about 10 or so).

PSU specs:

  • Input 6-30V DC
  • Output 8V DC, 2.5 Amps max.

As I don't have the budget for a DC Load generator, I'm looking for a cost effective alternative to test with.

I have salvaged a PC fan from a Dell Workstation. DA15050B12H - AVC 150mm Ball bearing fan, DC12V 1.8 Amps.

Will this fan behave as an analog of an 8 volt 2.4 amp load as I would expect? I'm about to do some testing and measuring, I don't really care too much about the fan, but I wouldn't want to damage the PSUs.

Are there better load generation tricks I could consider without spending a fortune?

dip2013
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3 Answers3

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I would just get a bunch of 10Ω, 10W resistors. Each one will draw 0.8A from an 8V supply, and you can connect 1, 2 or 3 of them in parallel to see how the power supplies behave at different loads.

Dave Tweed
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Your options are:

  • buy low-voltage (eg 12V, 24V) bulbs, connect them in parallel or in series (pros: low-cost, especially in case of larger loads, cons: probably have to build some box to hold the sockets for the bulbs),

  • buy multiple power resistors, connect them in parallel or in series (pros: moderately flexible load configurations are possible, cons: moderate cost),

  • build a controllable DC load circuit, with one or more FETs attached to a heatsink (pros: very flexible, cons: might need a larger heatsink, and probably a fan as well, depending on the magnitude of the power to be dissipated; higher complexity),

  • buy a controllable DC load circuit ready-made (pros: buying is simple, cons: higher costs).

Laszlo Valko
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The Arachnid Labs Re:load 2 starts at $15, but you may need to get the larger heat sink, which will cost $5 more.

Ignacio Vazquez-Abrams
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