I'm not too knowledgeable on electricity, but I'm constructing an electromagnet with aluminum strips as the coil and using a 120 volt household current. Proposing to solder an extension cord to the strip coil. 1. When it is plugged into the outlet, will it automatically send juice through the coil? or does it have to be triggered someway like an appliance's on & off switch? If it DOES have to be triggered, how do I do that? 2. I'm ordering some aluminum strips that are advertised to withstand up to 500 volts d.c.. The seller says he needs the minimum & maximum resistance (ohms) since the strip thickness depends on it. How would I determine the resistance based on 120 house hold volts? (I'd really like it to have a capability of withstanding up to 450 volts) Thanks.