#cathode  a negatively charged electrode that is the source of electrons in an electrical device
  exclusion:  #anode
  supertype:  #electrode  a conductor used to make electrical contact with some part of a circuit
  subtype:  #photocathode  a cathode that emits electrons when illuminated
  part of:  #electrolytic_cell  a cell containing an electrolyte in which an applied voltage causes a reaction to occur that would not occur otherwise (such as the breakdown of water into hydrogen and oxygen)
  part of:  #thermionic_vacuum_tube__tube__vacuum_tube__thermionic_tube__electron_tube__thermionic_valve  electronic device consisting of a system of electrodes arranged in an evacuated glass or metal envelope
     part of:  #electrical_circuit__circuit__electric_circuit  an electrical device that provides a path for electrical current to flow
        part of:  #electronic_equipment  equipment that involves the controlled conduction of electrons (especially in a gas or vacuum or semiconductor)

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