title: Emitter
text: # Emitter
  
  Emitter may refer to:
  
  ## Devices which emit charged particles
  
  * Cathode, or negative electrode, in a vacuum tube or diode
  * Anode, or positive electrode, in certain applications based on the emission of ions from a solid surface
  * One of the three terminals of a bipolar transistor
  
  ## Devices which emit electromagnetic radiation
  
  * Lambertian emitter, a light source whose radiance varies with angle according to Lambert's cosine law
  * An infrared LED used to emulate a remote control
  
  ## Other uses
  
  * A device used in drip irrigation
  * A compiler's code generator
  