In the schematic I saw, it is very important to note that the parts specified cannot handle the full roaster heater and blower load. It would b= e tempting to wire it as drawn and plug the popper in to the variable outlet. There would be two indications of the activity of the "Variac:" a.)- Voltmeter reading of the actual voltage output- b.)- The density of smoke issuing forth from the transformer if it is actually phased correctly to boost the incoming line voltage. You can wire the transformer correctly- or not. 50-50 chance of doing it correctly for V boost. If you wire it to buck the incoming line voltage, the output will be 0-95 vac. So you turn the dimmer up to blow harder and retard the roast, if it's only hooked to the blower motor with the heater directly wired to the incoming line power. In V "buck" mode, you'll turn it up, expecting the increased blow to put on the brakes... Max blow will only have 95V, instead of 140V or so it could have. Poor blower! Cheers -RayO, aka Opa! Got Grinder?