The Clapper is a sound activated electrical switch

Switch

In electronics, a switch is an electrical component that can break an electrical circuit, interrupting the current or diverting it from one conductor to another....

, sold by San Francisco, California

San Francisco, California

San Francisco , officially the City and County of San Francisco, is the financial, cultural, and transportation center of the San Francisco Bay Area, a region of 7.15 million people which includes San Jose and Oakland...

 based Joseph Enterprises, Inc and marketed with the slogan

Slogan

A slogan is a memorable motto or phrase used in a political, commercial, religious and other context as a repetitive expression of an idea or purpose. The word slogan is derived from slogorn which was an Anglicisation of the Scottish Gaelic sluagh-ghairm . Slogans vary from the written and the...

 "Clap On!" and as a separate phrase "Clap Off!". The Clapper works with any American standard electrical outlet.

Two upgrades have been made.

• The Smart Clapper allows control of two devices, based on if a person claps two or three times.
• A design revision known as the Clapper Plus includes a remote control function in addition to sound-based activation.

The Clapper can sometimes be triggered by coughing, a dog's bark or clapping that emanates from televisions and stereo speakers set at high volume, making it somewhat inconvenient for households with dogs and loud appliances.

There is also an away setting on the clapper that turns on whatever is plugged into it at any detection of noise. It can also be used to turn lights on whenever a room is occupied without having to clap.

The Clapper, whose slogan is "Clap On! Clap Off!", was first sold to the public on September 1, 1985. The melody of the jingle used in the commercials ("Clap on, clap off...") had been used earlier back in the mid 1980s for Sine-Off cold medicine, in a commercial featuring women at an army base. (The current version of the Clapper jingle uses a slightly modified tune.)

An earlier device with similar functionality had been marketed as early as 1965. A product from the Sonus Corp. called the Sonuswitch was discussed in a Time Magazine article dated October 29, 1965.