Public address system

src: upload.wikimedia.org A public address system ( PA system ) is an electronic system comprising microphones, amplifiers, loudspeakers, a...

Zigbee

src: upload.wikimedia.org Zigbee is an IEEE 802.15.4-based specification for a suite of high-level communication protocols used to create p...

AC adapter

src: s3.amazonaws.com An AC adapter , AC/DC adapter , or AC/DC converter is a type of external power supply, often enclosed in a case simil...

Smoke detector

src: www.funkidslive.com A smoke detector is a device that senses smoke, typically as an indicator of fire. Commercial security devices iss...