Electronics – Diode


  • Conduct electricity (Electrons) easily in one direction
  • Two lead semiconductor
  • Diodes are made by Silicon [mostly], Selenium and germanium [Sometimes]


  • A PN-junction diode is formed by joining together n-type and p-type silicon.
  • In practice, as the n-type Si crystal is being grown, the process is abruptly altered to grow p-type Si crystal. Finally, a glass or plastic coating is placed around the joined crystal.
  • The p-side is called anode and the n-side is called cathode.
  • When the anode and cathode of a PN-junction diode are connected to external voltage such that the potential at anode is higher than the potential at cathode, the diode is said to be forward biased.
  • –In a forward-biased diode current is allowed to flow through the device.
  • When potential at anode is smaller than the potential at cathode, the diode is said to be reverse biased. In a reverse-biased diode current is blocked.
  • + – + –


Water Analogy of Diodes

Various Diodes

  • Avalanche Diode
  • Constant Current Diode
  • Crystal Diode
  • Gunn Diode
  • LASER Diode
  • Light Emitting Diode(LED)
  • Photo-Diode
  • PIN Diode
  • Shockley Diode
  • Step Recovery Diode
  • Super Barrier Diode
  • Transient Voltage Suppression Diode (TVS)
  • Tunnel Diode
  • Thermal Diode
  • Vacuum Diode
  • Varactor Diode (Varicap)
  • Zener Diode





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