overkill,
You really want to watchout how much juice you put through that light dimmer switch. Your Dremel will be fine, as would soldering irons, etc. Small low power items are O K to run with these things.
For anything with a large, power sucking, heater element, you REALLY need a Variac. My strong suggestion is to get one rated for at least 15 amps. That way you are covered. That or stay away from any device that draws more than 1,000 watts and go with a 10 amp model. Your rough ballpark matching fudge factor is 100 watts equal 1 amp.
As an example, I run a 1,000 watt floor heater on a 10amp Powerstat variable transformer, which is what these units are called, and have no problems. I run at about 50%. Please keep in mind that one of these transformers can be cranked up to produce 140 volts, so use caution.
Check Ebay for these devices. You can sort of self educate yourself by viewing them.
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