1. (

• detector ,
• sensor ,
• sensing_element

) any device that receives a signal or stimulus (as heat or pressure or light or motion etc.) and responds to it in a distinctive manner ;

2. (

• detector ,
• demodulator

) rectifier that extracts modulation from a radio carrier wave ;

3. (

• detector ,

) electronic equipment that detects the presence of radio signals or radioactivity ;