I purchased a step-up/step-down voltage converter to use my 110-120V electronics in countries with 220-240V wall sockets. It's similar to the one pictured below.
These transformers are sold in a variety of Wattage ratings. What is the power consumption of the transformer? Does it always consume its maximum wattage capacity regardless of what devices are attached to it? If I just turn on my 1000W transformer with no devices attached will it be drawing 1000W, or some lower amount? If I have devices attached that add up to 1000W, is it transformer drawing 1000W or a different amount?