The lowly incandescent light bulb is a great current limiting accessory when testing or repairing electrical equipment, particularity vintage items with failing components. You can easily make a convenient device of this kind yourself, and a few different bulb sizes (60w, 100w, 200w) is all you need to test almost anything. A great practical application of the positive temperature coefficient of resistance of most metals - something you cant to the a CFL or LED bulb!