Soft On / Off Switch: Modern electronic equipment
incorporate "push-to-on-push-to-off" switches that do not make
the clicking noise as with old equipment. An example of this is
the power button on a ATX computer cabinet. Here is a circuit
that does the same. It can be used to turn on/off any
electronic/electrical equipment that operates on any range of
voltages. FAIR WARNING -- THIS SITE HAS ANNOYING POP UP ADS.
Telephone Line Based Audio Muting & Light On Circuit: The
circuit would automatically light a bulb on arrival of a
telephone ring and simultaneously mute the music system/TV audio
for the duration the telephone handset is off-hook. Lighting of
the bulb would not only indicate an incoming call but also help
in locating the telephone during darkness.