I am trying to design and build a load for adjusting and repairing power supplies. In the past, I've used the usual collection of auto headlamps, combinations of resistors, etc. with varying results but with absolutely no convenience or precision. My thought is to construct a bunch of relatively low current "modules" that, when used in varying combinations, would result in load currents from 1 to 100 amps in 1 amp steps. For example, 9 - 10 amp "modules", 1 - 5 amp "module" and 5 - 1 amp "modules" would accomplish this and wouldn't require expensive high current switches to switch them in and out of the circuit. Using a load like this would allow me to adjust things like current foldback much more accurately than any method I've used in the past. Calculating nominal resistances, effects of test lead size and length and so on is not my problem; that's all easily done. My dilemma comes with trying to decide what to use to construct these "modules". Nichrome is out because of its wide variations in resistance with temperature. Two possible candidates that I've found are Constantan or Manganin wire. I've spent several days searching the internet for information such as resistance per unit length, power dissipation (temperature), price, etc. with little to no result.
Does anyone out there have any advice/suggestions as to, (1) what type of material to use, (2) specs. and/or pricing on my two above prospects or others, or (3) any other comments about my proposed project. One final comment; cost IS a factor. I really don't want this project to get out of hand if I can help it. What that translates to in terms of dollars, though, I'm really not sure at this point.
Thanks for any and all help or advice you would care to offer.
Tom