Abstract: An adaptor for converting a 3-way electric light socket switch for convenient use with 1-way light bulbs provides an electrical conductor between the intermediate terminal of the switch to the central lead-in of the bulb and electrically insulates the central terminal of the socket from the components of the switch which correspond to the switch position which would normally energize the central terminal to produce a sequence of "on"-"off" conditions in the bulb from operation of the switch. A modified adaptor has conductors on each side for identical use in either orientation. A modified switch construction is also disclosed to provide optional use with either 3-way or 1-way bulbs.