Characteristics of Silicon & Germanium Diodes

Rectifier diodes are electronic devices that are used to control the current flow direction in an electrical circuit. Two commonly used materials for diodes are germanium and silicon. While both germanium diodes and silicon diodes perform similar functions, there are certain differences between the two that must be taken into consideration before installing one or the other into an electronic circuit.

  1. Silicon Diodes

    • The construction of a silicon diode starts with purified silicon. Each side of the diode is implanted with impurities (boron on the anode side, arsenic or phosphorus on the cathode side), and the joint where the impurities meet is called the "p-n junction."

      Silicon diodes have a forward-bias voltage of 0.7 Volts. Once the voltage differential between the anode and the cathode reaches 0.7 Volts, the diode will begin to conduct electrical current across its p-n junction. When the voltage differential drops to less than 0.7 Volts, the p-n junction will stop conducting electrical current, and the diode will cease to function as an electrical pathway.

      Because silicon is relatively easy and inexpensive to obtain and process, silicon diodes are more prevalent than germanium diodes.

    Germanium Diodes

    • Germanium diodes are manufactured in a manner similar to silicon diodes. Germanium diodes also utilize a p-n junction and are implanted with the same impurities that silicon diodes are implanted with. Germanium diodes, however, have a forward-bias voltage of 0.3 Volts.

      Germanium is a rare material that is typically found with copper, lead or silver deposits. Because of its rarity, germanium is more expensive to work with, thus making germanium diodes more difficult to find (and sometimes more expensive) than silicon diodes.

    Which Diode Should I Use?

    • Germanium diodes are best used in low-power electrical circuits. The lower forward-bias voltage results in smaller power losses and allows the circuit to be more efficient electrically. Germanium diodes are also appropriate for precision circuits, where voltage fluctuations must be kept to a minimum. However, germanium diodes are damaged more easily than silicon diodes.

      Silicon diodes are excellent general-purpose diodes and can be used in nearly all electrical circuits where a diode is required. Silicon diodes are more durable than germanium diodes and are much easier to obtain. While germanium diodes are appropriate for precision circuits, unless there is a specific requirement for a germanium diode, it is typically preferable to use silicon diodes when fabricating a circuit.

Related Searches

References

  • Photo Credit electronique 1 image by thierry burot from Fotolia.com

You May Also Like

  • Ideal Diode Characteristics

    Diodes are made from semiconductors such as silicon or germanium. Their most basic role is to block current in one direction but...

  • Types of Diode

    Although many germanium diodes were replaced with silicon due it its relative ease of processing and increased temperature stability; ...

  • Diode 1N914 Specifications

    While most diodes are constructed of silicon, there are some instances where a germanium diode may be preferred. For example, germanium diodes...

  • What Is a Signal Diode?

    "Semiconductor" is the name given to the class of material---including silicon and germanium---that neither allows electricity to flow as freely as conductors...

  • Difference Between Rectifier and Diode

    Diodes are devices made from silicon or germanium that permit electric current to flow in only one direction.

  • Difference Between a Diode & Zener Diode

    Diodes are constructed from semiconductors such as silicon and germanium. ... The Difference Between LED & Diode. LED stands for light-emitting diode,...

  • Different Types of Diodes

    The germanium diode uses a germanium crystal pellet as the rectifying element, the property that causes energy in a diode to flow...

  • Differences Between a Superconductor & a Semiconductor

    The most important semiconductor materials are silicon, germanium and gallium arsenide. ... An ideal diode, therefore,... Difference Between Rg59 and Rg6.

  • The Difference Between NPN & PNP Transistors

    Difference Between a Diode & a Transistor. Diodes and transistors are both made from semiconductors such as silicon or ... Characteristics of...

Related Ads

Read Article

NFL Memory Card Game for Kids

Others Also Viewed