A device that enables “smart” dimmers comprising electronic circuits beyond those found in traditional rotary dimmers to be installed in existing houses with no need for any new electrical wires. In addition, for smart dimmers comprising PLC (power line communication) modems, the device overcomes the large attenuation imposed on power-line communication (PLC) transmissions, introduced by a lamp in series with the smart dimmer, and eliminates the large noise and ringing otherwise introduced by the switching device, inside dimmers. As opposed to prior art, that compromises either the amount of current for the electronic circuits, or the PLC attenuation or both, this disclosure overcomes both.